@james set the channel purpose: All things mechanics.
Build a spartronics version? XD
practicing some cad right now, how far should we drop the middle wheel on the chassis?
Also can you move the gearbox to the rear of the chassis
Yeah I just need to do it without breaking everything
how do you break a joint between the chassis and other parts
Open the joint tab on the left side of the screen.
Then find the joint you want to get rid of and delete it
When you hover over the joints in the tab it will be highlighted on the model
is there a way to just move stuff without deleting the joints?
If you right click the part and then select move you should be able to move the part regardless of any joints
Then you have to delete the joint that attaches the part to the chassis
I am assuming you are trying to move the wheel down
If you are then you need to delete the joint that attaches the wheel and gearbox to the chassis
the problem is, it's hard to tell which joints hold the parts together and which ones attach it to the chassis
actually the non-gearbox wheels are made up of 3 parts which is a but annoying
If you highlight all 3 parts you can select an as build joint
It worked when I first turned in my computer and then I closed it because it wasn't updating and now it won't open again
and that is some weird sculpting stuff that I can't figure out
Will, Alex, Bo, could one of you share the t-shirt launcher file with me?
Is there a way to make the CAD open to everyone on the sub team?
You have to share it to all of their accounts as far as I know
Makes sense, we just need everyone to have an account
Is the 10:00 meeting this weekend on saturday or sunday?
Do any of you have any thoughts on the CNC debris collector? I currently can't find an clear benefit to either design, other than whatever design that we chose has to have a brush on it to work with the metal.
I'll look into it, we should probably figure out what will be best for our specific setup
Mr Chee sent an email about the add-ons with the email talking about the pegboard he bought. Three of the are things we have to build on our own, on is something we need to assemble.
Right. I was thinking we should see what other teams use etc
I think we could easily do it ourselves and it would be half the price
@victoriakleiven has joined the channel
The pegboards and tools should all be here by Sept. 23rd. We need to meet and organize. Can we meet Sat. 9/24 from 10 am to about 4 pm ?
I basically order duplicates of what we have. I think we need to label all stuff that goes on the peg board so it will not be confuse with tools that goes in our tool box.
Why is Alex not reading this ? I have extended my curfew with slack for tonight. No response mechanics ?
I could meet on the 24th anytime after about 11am
ok, maybe we should also announce to team after I confirm 9/24. It all depends if all the stuff is delivered by then.
Which would you label ? The tools that go on the peg board or the tools that goes in our toolbox.
And I think we should paint the handles a certain color
People need to know where to put stuff on the pegboard, but the toolbox is organized by section, not by specific tool
I just feel like the pegboard is the one that should be marked but it could be either one
I feel like the labels from a laborer would peel off
Labels will come off . We can wrap color electrical tape on the tools . Regarding the pegboard we can outline the tools on the pegboard once we commit to location .
I like the tape idea, maybe we can color code the drawers of the toolbox?
Another thing we need to figure where to place our pegboard . 2 options . Where the current Nvidia banner is or where the photos are hanging
Personally I did fine last year without color coding on the toolbox, and that was my first year. I think many would be the same
I think where the picture are hanging would be best
I like where the wall where the pictures are hanging but it is further away from the 2 mechanics table .
@lucas_rininger Some people aren't as organized, but it won't make it worse for the rest of us
I agree we don't need to color the tool box drawers. We just need to distinguish tools on the pegboard from tools in the toolbox . Make sense ?
I think we should mark the tools in the toolbox cause then at competition if we lend stuff they will now it belongs to us .
I don't think it matter that much for us as long as all the tools get back to the right place
@rose_bandrowski has joined the channel
Will, Jack, The current plan I have for the presentation for next meeting is we grab the scaling system, and the spare chassis that's been floating around, but only if we get to be in the shop (313). We should have a computer with Fusion 360 on it to show CAD as well. The scaling system isn't attached to anything, so we can show a smaller example of the engineering we do. Please respond/change the idea.
I like it as a demonstration, but we still need to come up with what we are going to cover in what order. I vote we start with a quick overview of how engineering splits up during build season, then go into the build the robot aspect, then cad, with a question period at the end of each category.
I'd save the questions for the end, but I like the order. Possible start out with what we do, and the fact that it's a bit more than just building stuff.
@bill_bandrowski has joined the channel
I missed the meeting and there wasn't any specific info on the leadership meeting notes. I'm curious as to what we're doing besides presenting about the various things that we do. Do we have a hands-on activity planned or are we just doing a presentation/ Q&A?
Reading it a little more closely it looks like we're just doing presentations today.
Pretty much, you can allow time for questions at the end of your presentation at the end though
hey folks if any one is interested there is a pretty neat documentary on netflix called "cosmodrome"
its about the Russians in the space race and how they were 20 years ahead of us in terms of their rocket technology with out anyone knowing because they lost funding the moment they had a space worthy prototype.
This is worth the hour of your life it costs to watch it
a nice summary of motors and motor controllers (cross posted to programming): a nice summary of motors and motor controllers: https://www.youtube.com/watch?v=5thxBgew7N0&feature=youtu.be
Can some of you (students) look at Banebots and come up with a list of wheels we should buy soon. Thanks
West Coast Products makes an interesting type of gearbox/wheel mounting system: http://www.wcproducts.net/ The WCP SS gearbox looks nice, especially in that it's easy to see if something is going wrong with it. But I think the Single Reduction Clamping Gearbox (http://www.wcproducts.net/217-4156) could be excellent for prototyping using VersaFrame tubing.
As an idea for an off-season project, I would recommend designing and building a winch system to fit in the smallest space possible. We've at least attempted to use a winch system on all of our robots so far (Atlas belt winder; Gaea forklift elevator; Ares scaling system), and it's likely to be useful in the future. I saw some nice designs on Chief Delphi that could give us some inspiration.
What are we(Mechanics+Cad+Electrical/Pneumatics?) doing for tomorrows meeting, and what still needs to be worked out? Last
I heard, we were going to a rotation system, but not much more beyond that.
Good question - there will mostly be stations for the machinery so people can get approved for using the shop. Also a small room tour (tape color coding explained). We need to decide specifically who will be doing what. @whobbs1496 @alex_lf
I thought Mr. Chee said that there wasn't going to be any tool approving tomorrow, that would happen at the meeting after that.
No new member is approved but you can Demo and supervise .
I'm thinking we have around 6 stations: CAD, safety, electronics, prototyping, and two stations for the tools (mill, lathe, etc.)
Would the tools be divided into showing the power tools as one station and the other station being for the hand tools?
And Prototyping covering the wood tools as well, or do we just integrate that into the hand tools?
We have 1 hour 45 minutes to cover 6 stations, so ~15 minutes per station. With six stations that means that one leadership person per station.
Should we save figuring out what were going to do for tomorrow and have all of us get there at 5:30? I doubt that we're going to be able to organize everything over slack.
That sounds good, we should assign each person a station and meet at 5:30 to discuss
I can do whichever so long as it is not electronics
Alex can you do safety for the drill press, lathe, or bandsaw?
I can do the hand tools, I still think we need a separate category for the hand tools, and have prototyping more for the wood based tools.
I would have a power tool safety for hand tools, lathe, mill, and drill press and then a section for CAD and a section for electronics/pneumatics
Clearly, but which ones have people not claimed
Fine, but do we at least have a list of which categories. Will, from your message, I got there is going to be a group for the Lathe and Mill, a group for the band saw, drill press, grinder, a group for hand tools, a group for cad, and a group for electrical/pneumatics.
Alex on Mill/Drill press. Kenneth on Hand Tools, Lucas on Band saw, Bo on Cad, Clio on Electrical.
I could stand having a second person to go over hand tools
OK sounds good, and are we still doing the 5:30
I don't know if a room tour is absolutely needed, the only things real left to point out is where we keep materials and parts.
if not a room tour please tell group where things are at least upon entrance.
Rose are you part of marketing orientation or touring mechanics?
I may help marketing if they need it although I doubt they will, Jon seems to have it under control
I think that it is really, really important to know where everything is. It saves you time and the person you have to ask for help's time
We could take the fist few minutes to divide people up, point out stations and do a fast room tour
I think that over complicates things you can just show the whole room where everything is, everything's pretty visible from the middle part.
It will probably work either way though
Do the room tour as an entire group from the center. I don't think we should go into to much detail, since most of it could still change Either way still six groups, see my earlier comment about timing, but more like 12-13 minutes with the brief room tour added.
I would suggest grouping everyone in the center and showing roughly where everyone is
Just point at stuff. "This is a mill. It mills. This is a drill press. It drills. This is a lathe. It turns." for 30 seconds then split up
exactly what I meant, we just need to know where the general is and stuff will likely be moved around anyway. People will get to know the room from being in it
Do think we need to point out generally where materials are, since we won't have a group talking about it. For example, point out the metal, the middle shelfs and prototyping parts.
Okay, meet at 5:45 then and run back to 316 at 6:05-6:10
You guys can meet right after school on wed to plan if you want . We need to fix Aries for girls gen .
I won't be able to be there right after school
I think we should be fine, as long as everyone read the chat.
We need Ares fix ASAP before Thurs. for the girls driving team to practice.
apparently the complete version of GAEA is in Onshape
Ok . Gaea is somewhere else . I will let you guys hunt . Clue : website
Did we figure out the bad link for the cad file for GAEA in our website ? Please consult with James .
It should go to someone's Dropbox ? containing our entire CAD files for GAEA . Please ask Will and Alex. I believe the Dropbox files belong to a student who was on our team 2 years ago . Elan ? Or we should ask Elan or Xander .
The link brings you to a Dropbox download but it gives you an error when you try to download
Go to our website and click on the last link for cad file of the full robot .
The link for the chassis works . Does this make sense Will ?
I only have tried to get the chassis file but the download on the chassis file does not work
Remember you were asking for the Gaea files last week ?
The download for the chassis files worked for me . I want the entire robot .
When we tried the download we could get it into his drop box but not from the Dropbox to the computer
That is why it is not working for you . Again we need to figure out the other link . Please contact Xander and Elan and find out whose Dropbox it is that is saved on
I was able to put the chassis file in Onshape but I have not shared with you guys .
I will share once we figure out the file for the entire GAEA.
James , thanks for asking but let's figure out whose Dropbox the files are coming from and then we can share with you to fix .
Anyone know Dropbox enough to figure this out ? I have posted and asked in Dropbox to the owner of the cad files . No response so far .
A file, which can't be shown because your team is past the free storage limit, was commented on.
A file, which can't be shown because your team is past the free storage limit, was commented on.
Will and Alex , do you have Elan and Xander contacts ?
@coachchee pinned their Post Online FRC resources for engineering and mechanics subteam. to this channel.
We still have a lot to do with the CNC (build a wall , test carve on metal ) , finish installing the lathe , and more organization . Who is willing to meet on Sat. Oct 29th from 10am to about 4 pm ?
Let's confirm early next week . Anyone else ? Kenneth , Bo , jack , rose , Clio ?
I'm not sure how helpful I'll be, but maybe I can help?
It's about learning the CNC and other mechanic stuff.
I can be there later in the day, had some plans but they won't take all day.
i can't prommise anything. I'm scedualed to work that day. if they don't need me ill be there
@andrew_peterson has joined the channel
@alex_larsonfreeman what account should I create for the cad software download?
Will can add you to the Spartronics folder, just make sure you let us know if you are using an email for Fusion which is different from the one you have on Slack
a great introduction to pneumatics! https://www.youtube.com/watch?v=JN9KCOp3hHA&feature=youtu.be
my email is the same as it is on slack
@whobbs1496 Mine too. And what time was the shop cleanup planned for?
@Kate Treviño-Yoson has joined the channel
@adrien_chaussabel has joined the channel
@jeremy_lipschutz has joined the channel
Reminder, next meeting there's going to be the safety test on the sheets give out last meeting. You need to pass to use any of the tools in the shop.
@Kenneth Wiersema what is the plan to ensure programmers stay safe?
@parker_hutchinson has joined the channel
nice overview on drivetrain designs here: https://www.youtube.com/watch?v=6lmKLTZZLBE&feature=em-lss
Thanks Dana . I will pin this PDF file. We actually used this file the first 2 years in engineering to teach drivetrains.
Good design file for drivetrain. Must read for all mechanics.
@dana_batali pinned @coachchee’s File to this channel.
Can someone in engineering check our inventory for 1/2 inch hex bar at our next meeting ?
If we are going to make an inventory system we better start digital
FYI we will be meeting on Saturday 12-17 from 11:30 to 4:30. We still have some work that needs to get done before kickoff and we will not have enough time during our other meetings to get it done.
Here is a list of things we will need to get done. 1) get the Suck it working with vacuum hose(build a system) 2) test the CNC 3) build the stand for the digital counter for the new lathe 4) Fix the 3D printer 5) unpack stuff from Vex 6) inventory various parts ( nuts/bolts, motors, etc)
computer numerical control. It is a computer aided router that can do precise milling operations. We have a CNC from inventables called the x carve.
if you go to inventables website you can learn more about it.
I have a printerbot play that we could use if we needed another 3d printer
I'm afraid we don't have a need for a 3D printer at the moment @tom_wiggin we apriciate the offer. Thank you for your willingness to contribute. We will know who to ask if we ever need another 3D printer besides the one that we already have.
I was hoping I could get some help with it really
it hasn't printed a single thing since I bought it and its still in mint condition but it just won't do anything at all no matter what I do
Tom, I don't think robotics is the best place for debugging your printer, but if you want help maybe ask for it outside of team meetings
Reminder don't forget to complete your CAD model. The model needs to be completed and dimensioned before you can build your part.
Hope it's ok that I ask here: Does anyone have an hdmi capture card that I can use at FLL? They are typically used with recording video games.
Reminder do not forget to finish your CAD design. It is due tommorow!
Mechanics! This Sunday we will need about 3 people to meet at 11 AM with Coach Chee and I to go to the lumber store. We will purchase materials for building this year's game elements! These are vital for testing our robot and simulating the playing field. Who's up for it?
I can help sunday for getting materials and building the items.
I only need 2 people . Alex and ? Alex please decide . Meet at Bhs at 11 am on sun.
I can take Kaedric since he was the first to respond, but all are welcome from 5-8 after the meeting
Here's a link that discusses robot size and how the kop chassis has configs that are illegal https://www.chiefdelphi.com/forums/showthread.php?t=153134
Happy to point students to some homework... The harder task, to read and consider the material, remains fully on their plates
Here's the plans for the team version of field elements, we might want to wait and see which strategy we're going with before building some of them. https://firstfrc.blob.core.windows.net/frc2017/Drawings/2017TeamVersions.pdf
@jacob_barfield has joined the channel
I found this article I remembered reading years ago (I'm a bit of a basketball fan) - seems worth sharing given the similar problem to solve when optimizing high goal shooting. With the lighter weight of fuel balls shooting off of flywheels, I think the effect (perhaps opportunity?) of ball spin may also need to be considered. Enjoy! https://www.wired.com/2011/10/optimizing-a-basketball-shot/
Just for fun, I created an illustration showing the parallels between the Wired article I shared earlier and the analysis required to try to optimize high goal shooting angle. If anyone wants to collaborate on this kind of analysis, let me know. Phun stuff!
A file, which can't be shown because your team is past the free storage limit, was commented on.
A file, which can't be shown because your team is past the free storage limit, was commented on.
I have ideas about how to potentially analyze air drag (do we know terminal velocity of the 5" balls?) & Magnus effect from spin as well, but it seems like a good starting point to leave them out. Agree it's good to have a Physics teacher as coach😀
here are useful CAD/Autodesk Fusion360 resources:
Field: http://www.autodesk.com/content/dam/autodesk/www/industries/education/docs/competitions-and-events/FRC_2017_Field_Fusion_360.zip KOP: http://www.autodesk.com/content/dam/autodesk/www/industries/education/docs/competitions-and-events/FRC_2017_KOP_Fusion_360.zip
this shows the "wide config KOP chassis" within the short robot volume (40" x 36"). No bumpers yet, but look at all the unused volume... This was a bit of a surprise to me and, if correct, suggests we may need to consider non-trivial modifications. Probably wise for a CAD student to check my work. The circle is a 5in ball. the dark big rectangle is max volume envelope. The chassis came from the Autodesk site referenced above.
(and yes, this model doesn't include bumpers)
Thanks !! I hope you students are reading this.
Aha... this is more like it... Bumpers are 3.25in thick. Corners are 6in... Now the wastage of the KOP chassis in wide config seems less-bad.
I have the square chassis file on fusion if you want it
started with the wide chassis to maximize intake
I was thinking square u shape for more storage
were you thinking of the tall robot volume then?
in stratgroup2 we were concerned with the rate to fill the hopper, more than the hopper size... All these aspects now need to be re-evaluated in the context of different shooter and intake design ideas.
I echo the fact that we need to be able to fill the hopper quickly in order to be successful. It would be good to determine some goal rates for filling and shooting so that designs can be quickly iterated early on, rather than getting in deep before we find out something isn't fast enough.
@whobbs1496 : i just concluded that the square chassis with bumper won’t fit in the tall robot volume. Perhaps you or a CAD student should double check.
I agree with your conclusion the tall option will not fit with the square chassis
both chassis within the short robot volume bumper (left is square, right is wide)
One consideration about whether to orient the chassis for a wide vs narrow side forward is maneuverability. A wider robot may be harder to maneuver around other robots. Also, I think it will leave less room to add a gear slot on front or back. I know the motivation was to be able to pick up more balls, so we'll have to weigh the pros/cons.
A file, which can't be shown because your team is past the free storage limit, was commented on.
Here's a minimal volume climber design concept I came up with on the ferry this morning, for consideration in case we go there. Created in Powerpoint since I don't have (or know how to use) CAD 🙂.
Probably would not need to be that wide - maybe just wide enough for 3 hooks instead of 7 as shown
Here are highlights from the Aim High season. Before setting on a design, it's always a good idea to survey proven ideas of others. If any of these ideas tickles your fancy, you can find more details in Coach Chee's copy of the book.
my focus here was on the interplay between intake, storage and shooting
Thanks for doing this. Again there are 3 opies of the book mentioned above.
Similar to what Dana shared, here is a "best of 2012" post on Chief Delphi that is very well done IMO. I think the high goal in that game is very similar to the high goal in this game from a shooting difficulty perspective. They had a larger, heavier ball (arguably more difficult than this year) but they also had things that made it easier like a functional backboard, a ball less susceptible to air drag and movement due to spin, etc. It would be good to look at the best high goal shooters' shooting mechanisms from that year. https://www.chiefdelphi.com/forums/showthread.php?t=106435
I just watched a match - wow that seesaw bridge was crazy!
very good summary of 2012! (i skipped to page 5 to get the last-most-updated version of the list and links)
A file, which can't be shown because your team is past the free storage limit, was commented on.
i can share or forward all my files, just haven't figured out the sharing features in fusion360
I can show you at the meeting today if you want
is it possible for me to share my spartronics project with all folks subscribed to spartronics, or is it more like I need to copy my project into spartronics?
Here a playlist of 8 of the 11 (3 day in robot reveal videos) in youtube that I created . I hope all have watched.https://www.youtube.com/playlist?list=PL-qLSGImlv5ScuC7X_tfr8KIzi8FwDGN8
coach - do you know if we have one of these from a previous kit of parts? https://www.amazon.com/Pixy-CMUcam5-Smart-Vision-Sensor/dp/B00IUYUA80 I do recall you mentioning that we have a pan/tilt system perhaps something like this: https://www.amazon.com/Tilt-Servo-Motor-Pixy-CMUcam5/dp/B00IVOEN1Y
napkin math, fuel volume
v = 5³ ** pi ** 4/3 = 523.599, percent unused space for "pouring" balls in <https://en.wikipedia.org/wiki/Randomclosepack#For_spheres> =
39.1%, 24x40x30" dimensions minus 7" each side for bumpers,
33**29**18 = 17226in³ internal volume, assuming literally every inch is ball storage,
(17226 ** (1-0.391)) / v comes out to a hair over 20 fuel. that seems low, how does one actually calculate this? :)
@dana_batali I'm fairly certain that we don't have the CMUcam (any version) in our inventory. I've looked into that camera in the past, and I think it's worth investigating.
@jack I think there is something wrong with your volume calculation for a fuel ball. The 5" diameter ball will fit inside a cube of 5" edge, so the ball must have a smaller volume than (555)=125
Calculating how many 5" cubes would fit into 17226in^3 gives 137 (although the dimensions of the robot internal volume will probably clip some off of that by not accommodating an integer number of cubes in each dimension...)
Ah, I think the volume of the sphere is 4/3piR^3. The diameter is 5, so the radius is 2.5
@dana , No we dont have https://www.amazon.com/Tilt-Servo-Motor-Pixy-CMUcam5/dp/B00IVOEN1Y
Additional plywood outside building doors (flag pole). Can someone bring out into the lab?
@declan_freemangleason has joined the channel
Students in mechanics, you will be getting some research homework from your Captain (Will and Alex) on Sat. afternnon. Please do especially if you are on the team for school credit. To get class credit, various HW will be assign by me or the captains.
Another idea sketch: Goal is to optimize gear position to reduce gear cycle time
Elaborating on a concept I tried to convey at the town hall last weekend. Achieving high precision (different from aiming) may be the hardest engineering problem of high goal shooting to solve.
No problem - I felt like I didn't really land the concept very well at the town hall. If you decide to try the testing platform at lower right in the image, I think it would be better for the ladder to be positioned at the center of the long side of the plywood after considering it a bit more. Folks, on all these posts I make, they're just ideas/concepts for consideration... use or discard them as you like 🙂.
Thank you for distinguishing the difference between precision and accuracy .
Bellow is the research homework that everybody must complete for tomorrows meeting. You will either be assigned to research the launcher or the intake of one of the robot in 3 day teams. Also everybody should look at the hopper system. Bring notes with the pros and cons of each design. Two of you will also be assigned to the 2006 game Aim High. If you have any questions feel free to ask.
@Harper Nalley : ri3d 1.0 launcher @seanhooyer : Greenhorns RI3D launcher @parkerhutchinson : Snow problem Ri3d launcher @andrewpeterson : national instruments ri3d launcher @kaedricholt : Tesla ri3d launcher @CruzStrom : Ri3d 1.0 intake @ashtonbillmaier : Tesla ri3d intake @fiona : greenhorns ri3d intake @jacobbarfield : zou keeper ri3d launcher @rosebandrowski : snow problem ri3d intake @robert_galvin : Aim high 2006 launcher @sholzer : Aim high 2006 intake
You can find the ri3d reveal videos can be found here https://www.youtube.com/playlist?list=PL-qLSGImlv5ScuC7X_tfr8KIzi8FwDGN8
@ashton_billmaier has joined the channel
Here's the spec/gear ratios for the tough box nano, for the highest Rpm configuration, we want the 5.95:1 gearbox. https://docs.google.com/document/d/1D3tw8TKgPdiBg_zBvu2uBLtupzHnt0bGEg4_1KrOiHE
Let's make sure we have all of these gears during the meeting today
No, using the no load rpm with the gear box gets us to 892 rpm, which goes to 15 ft/s with 4 in wheels. As the motor will have a load on it, I don't think that we're going to get 15ft/s out of it, I'm confident the robot speed will be greater than 10ft/s.
Interesting thread on game pieces, specifically fuel balls breaking down. We may need to account for this as field reset won't be able to replace all of the balls https://www.chiefdelphi.com/forums/showthread.php?threadid=153622
@Kenneth Wiersema I was imagining that you were talking about the flywheel, sorry for the confusion
The gear reduction for the gear boxes are 10.71:1 using a 16 and 48 tooth gear combination. We still should get 6 more 24, and 40 tooth gears, and 4 more of the 16 and 48 tooth ones.
@Kenneth Wiersema , remind me to show you the gear hex bore reduction from 1/2 to 3/8 inch for the gears. So we are building on Mon. 8.45:1 and we have all the gears for 4 gearboxes ? Please give Robert the orders for the gears. I want to put in an AM order by Mon afternoon.
Yes, we are building the 10.71:1, using the gears from the kop. Will has the information, so I assume it was passed on to Robert.
@Kenneth Wiersema , please make sure we put a note in both KOP chassis of which gears we took out and are using if you have not. Thanks
I will also order for 8.45:1 because High RPM will mean low torque and 5.95:1 might just be too low of a torque to move the robot.
40T 20DP 0.5" Hex Bore, Steel Gear (am-0178) , out of stock , only able to get 4 instead of 6. Remember everyone and their mother is ordering. SO PLEASE ASAP orders !!!!!!!
@Kenneth Wiersema @whobbs1496 , please go to AM and request email when the above gears are avaialble and let me know
should we order 6 vex omni or 6 inch AM omni ? Do we have 6 inch fro rear and type ?
I missed the drivetrain conversation two meetings ago. Just catching up with you mechanic engineers. How was 4 wheel ( 2 front omni and 2 rear tread wheel decided ) vs 6 wheel tank drive. Please see:
Again. Especially starting around pg .80. Maybe we should drive Atlas ( 6 wheel tank drive ) shorter wheelbase and compare to our current drivetrain of 4 wheels ( longer wheel base ). Will the omniwheel improve maneuvering? But make us more prone to being pushed around .
Captains ? No answer? I ask cause by choosing our current configuration we just added about 10 hrs to our drivetrain assembly and chassis. Yes 10 hrs. (2 build sessions) Whatever drivetrain we finish assembling today will not be the final one and we still have to retrofit our chassis to fit the Toughbox nano and whatever u shape you guys decide. Lets see it on CAD before we physically assemble today. So be very mindful how each decision will affect the next. KISS !!
Do we need a second U shape chassis kit? And aside from the 6 6in wheels and the 2 pulleys is there anything else needed, since I can't think of anything else.
Whatever gears we used in the gearbox (Unless we have spares) and we do need another U shape chassis kit
The order that we did for the other gear boxes has the gears we need for the gearbox.
I know that 4 of the CIM motors are going to be used for the drive train, but what of the other two?
Other modules, I would like to try to save one for the climber(if we get there), and the final one might go to storage/agitator?
I think the agitator system would work with a window motor but I'm not sure
Right now . 1 cim for launcher. 1 for intake . 4 for geardrive . The climber will use the motor that we use from last year climber and stirrer not a cim
The motor we used last year for the climber was a cim with a 70:1 gearbox,
ok, then it would be the motor from Gaia that was use to lift the elevator system.
It was great to see the progress on shooter prototyping yesterday! One thing I saw in a team video that I think might be useful: Get a long piece of pipe big enough for the balls to roll down (6" diameter will probably do, but 5" might be better) and use it to test different shooting rates. Like these this video: https://www.youtube.com/watch?v=Ezf6wL_2WK8&feature=youtu.be&t=6m. The steeper the pipe, the faster the rate. I'm not sure if the prototype could be reconfigured to feed from the back, but that could help as well.
That whole video's worth watching actually - seems to be a Canadian RI3D team. The team has other videos as well, including a reveal: https://www.youtube.com/channel/UCFfnvW0xNa_bEDZy_-nCEkg. They even subtitled the reveal for English speakers - here it is: https://www.youtube.com/watch?v=_6HMjVVyCMI
btw: this video calls in to question the idea that a gravity-fed solution isn't fast enough. Their tube shows that they can feed more that 5 balls/second. They do have accuracy issues, but that's likely to do with the fact that the wheel speed is too variable.
this robot also shows that the gear and the intake can both be on the same side (front) of the robot. This might be desirable for ease of driving as well as video-camera feedback (we'd only need one cam, not two)
also seems like they may have selected the small/square KOP chassis - this limits the volume of their robot, but probably made it esaier to complete in 100hours
Thats cool. @dana_batali I'm glad we didn't go with that idea now. They had a far superior prototype and it still didn't work as well as the roller intake.
This is one option for our bumpers. We can also customized our bracket system for the bumpers as we have in the past. Between this Lucas'posting about bumper http://www.robopromo.com/category_s/1825.htmand this kit , the bumper team have enough to work on. Bumper team ?
I can't tell based on the page whether or not this is meant to be used with reversible bumpers. It just says "can be used to make a set of red and blue bumpers" Can anyone tell one way or another?
Does anyone know which file in our Fusion 360 is the current chassis configuration?
motor/stall/current table: http://cdn.instructables.com/ORIG/FD4/7RJ7/H4VQGXSA/FD47RJ7H4VQGXSA.pdf
snow blower is: am-2235, window is: denso 262100-3030
for the intake team, instead of building rollers from scratch I suggest you look at Mcmaster
Let me know what will work so we can order. It takes about a week to get from Mcmaster.
Also for those on the intake team (Sophie, Fiona, Ashton, Lucas) please do research on which polycord we want, texture ? diameter (based on minimum pulley size), hollow vs solid, Let me know by Friday so I can order.
Pretty good thread on chief Delphi; suggests using flat Polycord: https://www.chiefdelphi.com/forums/showthread.php?t=153426&highlight=Polycord
And a thread on pulleys: https://www.chiefdelphi.com/forums/showthread.php?t=152317&highlight=Polycord
Launcher group: Do we want to do some more prototyping on different flywheels ? Currently we are using green Banebot wheels (about 6 inches) . Those green wheels will wear out easily and will need to be replace. We only have 2, so we may need to order more. How about some research on CD for the best and different types of wheel for the fly wheel ? Check out AM, and Banebots site.
2815 used polycord in 2009 and 2012. Both times, we used some ABS or Delrin rod from McMaster, cut the necessary grooves on a lathe, then broached it for 1/2" hex.
FROM John again. Do your HW and read !!!! Intake team and captains.
or simply use pvc as rollers and cut some grooves and use these bearings
Green wheels are 4 7/8 inch not 6 inch. Green means ? Durometer scale , the softest. Do research on what durometer means and report back about color and meaning ?
We need to order some polycarbonate from online metal of various thickness to bend for launcher and for the hopper box.
Someone please give me order ASAP from http://www.onlinemetals.com/merchant.cfm?id=270&step=2&top_cat=181
What should we use as our base for our electronics this year ?
Nevermind on the online metal order request. Done.
We have a $40 voucher from Inventables ? What do we need ?
I happened to be around the evening they traded the mini cim for the full cim on the shooter prototype and saw a significant improvement in flywheel rpm recovery time after each ball shot. Lucas has told me a cim won't be needed for the intake motor, nor will one be needed for the climber, which I think means there is one cim left to use. A hypothesis worth testing might be that the flywheel rpm recovery time could be improved even more by using two cims to drive the flywheel... If the hypothesis were proven true, it would allow for shooting at a faster rate and/or with greater precision due to less falloff, either of which would improve effectiveness. Regarding testing with another more resilient wheel, could be worth doing if the current soft-surface wheel will require frequent replacement due to wear.
Do we need to run the launcher CIM at 100%? I am hoping not, since battery drop will result in shorter shots at the end of the match. If we are not at 100%, then the inclusion of an encoder on the launcher shaft will allow the motor controller to perform PID speed control, resulting in much faster speed recovery after each shot.
It was not running at close to 100% I don't think, but others will know for sure. Question: is it a viable idea to run two CIMs on one wheel (wire serially maybe). I still have a lot to learn about those motors.
Also on shooter, GREAT points from user Ekcrbe (post 4) in this thread: https://www.chiefdelphi.com/forums/showthread.php?threadid=153955
It is fine to couple two CIMs mechanically together. That's how the drivetrain is powered - the CIMs are driving the same gears, and cannot spin independently. In this configuration, we would run two motor controllers together, either with one in "follower" mode (CAN Talon), or just splitting the PWM control cable to control two standard speed controllers. But still, you'll get better bang for your buck by adding the encoder and letting the control system do the work of maintaining shooting speeds.
@riyadth : the thinking in the launcher programming subteam is that we'd run in constant velocity control mode... For this to work at all we'd definitely not be running/targeting 100% VBus in order to have extra juice to recover. There is a target RPM that we need the flywheel to spin at, so it's possible that a gearing stage would need to be introduced to balance all this out.
Indiana seems to have a robot somewhat similar to ours, that bodes well.
Indiana couldn't shoot, and what I thought was a launcher would be inaccurate.
Hey guys! For anyone interested in thinking about the scaler and what something like that might look like, head over to #climber for some brainstorming and discussion. If you have ideas, that's the place to post them!
A file, which can't be shown because your team is past the free storage limit, was commented on.
intake, hopper, launcher, gear grabber (passive), climber
FYI reminder again from FIRST: A quick heads up – for the first time in my experience with FIRST, this year’s sizing of your robot INCLUDES the required bumper assemblies! What this means is that when your robot is inspected, the maximum volume specified in R03 of the Game Manual will include the bumpers required by Section 8.5 of the Game Manual! Plan accordingly!
Further, the maximum volumes indicted in R03 and shown in the Figure at G04 enclose the dimensions your robot can extend to. That means if you have scoops, funnels, lips on hoppers, etc. that are contained within your frame perimeter at the start of the match (as they must be by R02), these items can extend no further than the bounds of the indicated maximum dimensions. You are advised to built your robot smaller than the volume in order to give your extensions room to expand beyond your bumpers, if necessary, after the start of the match.
Don’t think of these volumes as the size to which you need to cut your chassis!
Start thinking NOW about your bumpers. As soon as you assemble your chassis frame, go ahead and cut your plywood bumper backing and attach it to the chassis. That way, you will know how your bumpers will be attached, what spaces you have to work with, and where you can attach other robot components.
interesting thread on how much power teams are allocating to different systems: https://www.chiefdelphi.com/forums/showthread.php?t=153965
What is the RPM of our drive train? Asking for intake gearing. Apparently our intake should be geared twice as fast as our drive train.
Posted this a while ago: Just thinking about the cnc, here's a replacement waste board that I found https://www.inventables.com/technologies/waste-board-with-threaded-inserts we would want the 1000mm board. Just thinking whether we want to replace the waste board or not.
Correction on my previous comment. The intake should be geared to move twice as fast as you expect your robot to be moving
What does that bring the output rpm to with 2 cims?
Not sure with the two cims, but I was getting 471 rpm with cims running at 75% power
@Kenneth Wiersema How were you measuring RPMs on the CIMs? And I assume that 75% power was based on the motor controller PWM, correct?
I was using the specs found on the websites, I haven't done any actual measurements
I ask because CIMs should run at above 5000rpm unloaded, and your measurement is an order of magnitude smaller. Maybe it's on the output of the 8.45:1 gearbox that you measured 471?
OK, that makes some sense. But I expect that with any load at all, your RPM out of the motors will be significantly reduced. Friction of the gearbox will slow it down quite a bit by itself.
Yes, 75% of 5310 is 3982, and 3982 divided by 8.45 is 471
I didn't measure anything, I did some math with the specs
The actual question that needs an answer is the ground speed of the robot. This is because when the speed of the intake is <2x the speed of the robot, the balls will bounce off rather than get sucked in
I if there is, then measuring it when the weight of the robot is the lowest it will possibly be would be ideal
Ground speed of the robot will be limited by the ability of the drivers, more so than the motors. But Kenneth's computations give you an absolute maximum speed.
Because the speed of the intake needs to be at least twice the ground speed of the robot
We would have to put the chassis on the ground with some weight on it (to represent the finished bot) and run it over a distance while timing it.
So doubling up on the speed when the robot is light would give some room for error
Remember, the driver can slow down (or programmers limit the speed) while collecting balls.
True- i doubt that we'll be driving full speed while intaking balls
Just calculate the circumference of the wheel and multiply that by the rpm and do a few unit conversions to get the ideal ground speed, and reduce it by what ever amount you think is appropriate
I guess the question is, what should the speed of the robot be while collecting balls? Maybe we can estimate that based on how many balls we want to collect in how much time..
With the current gear reduction you are supposed to get 12.7 ft per second
I'm just gonna jump in and say I don't want to collect balls at max speed
Ok, ideally we want to be able to intake while going at our max speed, because time is everything. I'm going to use that estimate to decide on the gear reduction for the intake
Not always intake balls at max speed, but have the ability to
If we have a 'best speed' for collecting balls, we can have the programming team make a mode of the drivetrain where it can't go over that speed. (Override-able by the driver)
Question- would "ideal" speed of the intake = pidiameter of shaftrpm?
Rather, would that be how you would calculate the speed of the intake
then set that equal to twice the ft/s of the robot
@alex_lf I remembered this question & answer:
Paul Vibrans [10:43 AM] What is the shooter's angle from the vertical for hitting the high goal from right in front of the… Alex Larson Freeman [11:52 AM] About 8.3 degrees from the vertical
I wanted to double check: Is that the angle assuming the shooting mechanism is butted up against the boiler? If the shooter is at the rear of the robot, will the angle need to be a bit less steep?
Request: If you have a few minutes (study break?), please go to the climber channel (join if you haven't already!) & help crowdsource the pre-design analysis. There's a Google sheet in which knowns, requirements, & solution options are being captured. Thanks!!!
Chris R. recommended this for our pits. and maybe our robotic room. If someone is interested please research in Amazon and send me link for pricing .
I saw this CD thread a while back, and it seems like there are some tips & recommendations that could be helpful: https://www.chiefdelphi.com/forums/showthread.php?threadid=153999
Ideas for mounting a motor/gear reduction to drive this shaft?
Climber update: team update 5 clarified that Velcro is absolutely usable and a loop around the davit fingers may be used as a retaining feature. reposting some things from the climber channel here - the net is that while LIA is current top priority, reserving space for the climber is a requirement for LIA - this is my opinion - see below...
Chris Rininger [10:52 AM] With these and other clarifications, they have really made climbing doable. The most prominent field pieces are the airships - even in district matches they want the spectacle of robots ascending for takeoff! And so they're making it doable. I thought the hard part was going to be connecting the robot to the rope, but Velcro works for that. Now I think the hardest part is stopping at the top so there is sustained pressure on the plate (without burning out the motor & without breaking the dang plate). From looking at Chief Delphi, I believe over 90% of teams will attempt to climb and I believe over 50% of teams will be able to do it reliably - too many points to leave them on the table - better believe teams are investing in this. I personally view this as a must-have. Viva la escalador! (edited)
Enrique Chee [11:17 AM] Good to see you are reading rules. Hope the students are . Again, I agree about having a climber but the priority is LIA right now .
Chris Rininger [11:28 AM] agree... just need to reserve some volume somewhere on the robot for the climber... can't afford to achieve LIA in a way that prevents climber IMO - should be on the list of requirements for LIA
But you also have to account for the weight of everything. Mr Chee was talking to everyone yesterday about the weight of the robot and with all the things were putting on the robot it's probley going to be close.
If we cut with Michaels CNC on mon , you guys need to get the wood out of the robotic room and store it in the hallway outside my class . Please do asap .
curious what the implications of this placement are for driving/approaching the rope
That version of the CAD doesn't include a final gear holder, so that's going to take up some of the space along the back of the frame
But I like the placement, we should make sure no electronics are going there before we make a decision
From a driver perspective, it would be nice to have the gear side camera on the same side as the climber so it's easier to line up
If the climber is low there might be a way to place a visual reference higher up on the robot for drivers to use to "aim" the robot at the rope
In the past we used a small flag from a bike, maybe something similar?
something like that - maybe a little yellow propeller
if need that spot for gear (because there needs to be open space behind for the spring to thread through), then could look at one of the corners on the intake side as well - they seem like pretty small spaces though
Not sure you'd have enough room there but we can probably make the back corner work
Interesting thread on CD about maximizing shooting rate... there are a lot of advocates of increasing flywheel mass (along with closed loop control). One recommendation I thought was good (in post 10) was to set up gearing so the motor rpm at shooting speed is around 60%, allowing controller to spike power for recovery after each shot. https://www.chiefdelphi.com/forums/showthread.php?threadid=154712
fyi - this is more or less our plan without specific percentages for recovery rate... good to hear we're not on a bad path
Hi, I was going to look at the "final" F360 assembly because Bo told me some volume is now reserved for the climber, but I can't seem to open the file - says it is in the middle of saving, & it also fails when I try to open a past version. Any advice?
Also, from a link to FRC2877's pictures of the Steamworks unveiling that Riyadth shared, I copied some key pictures of the gear spring and lift.
It is probably failing to open because someone else is saving the file or is editing it
You can try just waiting for it to update locally, the latest version may already be saved but not on your computer yet
My guess is someone shut off their CAD staton today while the file was still saving when you do that fusion has issues
ah, makes sense - Lucas said something like that also - thnaks
Was anyone able to clean up and finish the CAD over the snow days? Seems like there are still open questions that will slow us down if not dealt with soon. Like how are all the currently freestanding posts tied together to make a stiff and solid structure? Mounting of the climber? And finalizing the details of the intake, like the curved backplate?
At tomorrow's meeting, do we need to go team by team and detail how we get to done? Maybe team leads can come to the meeting with a starting list?
I haven't been able to finish what I was doing but hopefully I can get it done before the meeting tomorrow
What have you been doing ? 2 extra days of no school !!
the file is currently being saved by one of the CAD computers which was not shut down properly
Why did you not mention this so we could have gone to school and correct this problem ?
There must be a way around this CAD issue. Bo ? Will ?
I don't know why you or Alex did not suggest going to school the last 2 days and correct this .
We can work off version 40 of the assembly which is the latest one to be saved properly. Versions 41 and 42 are mid-save
If I remember correctly those two versions are only different in that they include some climber parts and the agitator system I was working on
but that agitator system is built elsewhere and can be dropped into the assembly
Neither was I until earlier today but it looks like it's not too bad
Tommorow we need to go over how to save everything properly so we do not have this issue again
Chris our mentor posted back on Sun. pointing a problem. Did you guys not think about a solution. See his post and yours (Alex on Sun) .
@coachchee commented on @chrisrin’s file I cannot open the most recent two versions but I can open the one before that. Looks like this...: reposted from Sun.
This is exactly what I see now. By opening v40 the file will work.
Ok, lets see what can be done before our meeting on Wed.
I think we should also go over making separate assemblies then dropping them into the main robot assembly rather than always working off of the final robot. This would make it way easier for us to share files without overwriting each other.
The agitator is built this way, so I can drop in the parts I'm working on whenever
Maybe contact Parker and Andrew. Parker was not there on Sun. Looks like Parker was messing with it. and Andrew version 42.
It's also possible they were never logged out of their computers
I will see what I can do before the meeting tomorrow. Signing off for the night.
In the next meeting or two the team will be making design decisions about the final climber for the robot (as soon as we know location/volume constraints). If you want to be in on that, please join the climber channel if you have not already AND please review the "All Things Climber..." compilation of rules and Q&A answers I created.
Here's the 2017 inspection checklist v1 https://firstfrc.blob.core.windows.net/frc2017/AuxDocs/2017FRCInspectionChecklist.pdf.
Quick question: Given the functions on the robot this year, how well are people thinking the battery is going to hold up by the last 30 seconds when it is time to climb? Paul mailed me his assumptions and calculations about the climber motor, etc. including projecting an optimal gear ratio, and one of his assumptions is the battery will be somewhat low on power by climbing time. Just testing that assumption. Thanks
*Thread Reply:* Related: Paul's comment about battery drain made me curious, and I've been reading a bit about batteries, the need to test (including drain patten) them regularly, and also some stories about batteries having some cells not working optimally after impacts (seems like there were a lot of impacts last year via defenses). What's the team's battery management/test/refresh approach?
While analyzing the climber I learned that many teams use JVN's Mechanical Design Calculator as they work on design of motor-powered robot mechanisms. It basically includes all the FRC motors, data from tests of the motors, and frameworks for different mechanical scenarios using the motors you can plug into. Here's the latest one from early 2016.
I want to raise a risk related to the climber... With the location of the climber being the corner at the chassis level, we need to think about (& we'll need to test) how the robot will tip up & how it will hang (& potentially swing). I think there's a fair risk that the opposite corner of the robot, specifically the top of the intake, will contact the ground. It is possible we'll need to structurally reinforce that part of the robot, and I would not recommend locating anything (e.g. camera, wireless tranceiver, etc.) potentially sensitive to impact in that area either. The climber may climb fast enough that this risk doesn't turn into an actual issue, but when I visualize the climb in my head I do see an impact - just not sure how forceful.
Right now the radio and the RSL are going to be located at the opposite corner from the climber
Those can be moved but right now the part of the robot that is most likely to be damaged is probably the intake, since if it gets out of alignment it will not work, whereas the radio and RSL can still function if they are knocked around
@channel Launcher: Kenneth and Rose Agitator: Jack C and Julian Intake: Lucas R and Fiona Climber: Conrad and Samantha Gear: Sophie and Andrew Bumpers: Robert and Lucas N CAD: Bo and Kaedric Electronics/Pneumatics: Adrianna and Peter
HELIOS: Cruz ATLAS: James S
Uh, room plan for open house looks crazy crowded. I'm trying to imagine 60+ visitors in that space, which is smaller than Mr. Chee's room. Any way to move bumpers and climber out to hallway or another room? Then you would have more circular flow. Just a suggestion....
looks like you're selling t shirts but you can negotiate with Jack Chapman or Julian to trade
I will not be able to make it to the meeting today due to a sickness that I picked up yesterday
@Ethan Rininger has joined the channel
Hey guys, I never got Fusion 360 on my computer and I wanted to try tinker with it but the autodesk site is being rude and not letting me download the free student version, how should I go about getting it?
It's like log into the site and you can download it but when I log in it just keeps saying the same thing lol
Okay I stupid it needed me to verify something (to my credit, they weren't being clear). Thanks sovick
I can help if you need help actually using it.
One of my robotics photography projects this year involved gathering ideas for custom robot controls & drive station. Here's a collection of pictures from district champs and worlds. I really like the ones that are modular in that they keep the same drive station from year to year, but a section of the drive station is a robot control module specific to that year's game. Each year - new game - new control module. Some of the controls at worlds were really slick, and from talking with the teams that created them, the projects to create the custom controls were surprisingly doable. Hope y'all like these 🙂. https://1drv.ms/f/s!AikCDwtdoW5Lqj66386jgdCO_tXj
*Thread Reply:* here's the Customer Control Interface (CCI) several of the teams used - there are probably others... https://www.estoprobotics.com/estore/index.php?_a=viewProd&productId=33
Closing out 2017 robotics photography projects. Here's a set of high performing shooting robots from Houston. This could be helpful to the summer BARN project... https://1drv.ms/f/s!AikCDwtdoW5LrRy1-yYJ9ExJlWAk Of course, it would be a good idea to also check out online pictures of the top St. Louis shooters. 🙂
*Thread Reply:* Speaking of St. Louis, here's a high res pic (you can zoom in to see up close) of 254's bot: https://media.team254.com/2017/03/902d07bd-misfire.jpg
Per Rose's suggestion, copying this here from marketing @channel I was looking for a contact on Chill Out to send some pictures I took during the Worlds quarterfinals we shared with them, when I ran across this Facebook post on their page from someone on the Skunkworks team. Considering the fact that our team has learned quite a bit from Skunkworks, from their pre-season workshops & other interactions, I think it would be a good thing for a couple students to write supportive emails as requested. Here's the post:
Thomas DeSilva (May 2 at 10:11pm) Skunk alumni, family, and friends of the team: We need your help. For those of you who haven't been in the loop, we've had a rough year. We no longer have the same amount of support we once had, chiefly from the school's and the district's administrators. We need to show them the value that our team has to our students and to our community, and we need your help to do it. If you're an alumnus, a parent, a mentor, a FIRST volunteer, a member of another team, or anyone else with a story to tell, please leave us a note (or an essay!) at firstname.lastname@example.org. Tell us who you are and about the positive impact that our team had on you. It doesn't need to be long; we know that you're busy and we appreciate anything you can do for us. Please try to let other people know about this--especially those whom I'm not connected with or aren't on Facebook at all--as it's important. There's a lot on the line here. We want to hear from you. We need to hear from you. Thanks for reading, and remember: "Once a skunk..."
*Thread Reply:* Cool! It looks to me a little like a flying transformer. Structures that expand/contract like this seem to be a trend. I heard on NPR a couple days ago about a space station module being tested that is compressed during launch and then expanded once in space.
*Thread Reply:* Thats so cool oh my gosh I love this idea
*Thread Reply:* The future of mobile homes looks good.
*Thread Reply:* What impressed me was the quality of the space despite its extreme capability for compactness. To relate to what you said lucas_nalley I think this puts RV's to shame.
*Thread Reply:* Yay! No more caravanists!
*Thread Reply:* I just wish they looked better. The paint job on those things is straight off of a 1980s disposable paper cup.
*Thread Reply:* I would assume that one can paint them.
Kenneth can better answer this question as I've been gone for the past few sessions due to college visits but last I saw the shooter was doing well and the design coming along. Apparently we have some 3D printed gear covers now for safety. We had the gearbox lock up due to lack of lubricant but that was fixed. The shooting accuracy seems to really depend on how the balls are fed in and I think that was tested some by putting some scrap wood on it to make a fixed feeding system however I wasn't there to see so I'm unsure how well that was working. Regardless, if you fed the balls on right they'd go quite far/high and was generally very successful.
I may be disillusioned but I think if we get a good feed-in system the shooter could do quite well as it's really only supposed to be an adjustment to the trajectory and speed of the ball.
Rather unsure at this point whether we will be able to finish it before girls generation though.
*Thread Reply:* That Is AMAZING! that is such a cool resource! Thanks for sharing that!
I don't want to assume so I'm asking. We are not going to attempt finishing the shooter for Helios before girls generation, correct?
I thought the leadership team's general consensus was that we weren't going to finish it, as we would need far too much time to do so, that we don't have.
Okay I wanted to confirm, thank you.
Curious, will be want to finish after girls generation?
We didn't discuss that I don't believe
I would ask why, but we can, if we think it would be educational for the new people.
Could be cool for showing off the robot (outreach), and good for teaching newbies.
I still think Atlas is the better show robot, but with ~4 meetings to do so, I doubt we could finish it.
True. We can consider it, lets discuss it at leadership next week
As an separate assembly maybe, but not mounting. Taking apart Ares would be easier
That would be interesting (for lack of a better word, sorry), but I think building is more valuable than disassembling.
Since in the long run that is what we need to be teaching them how to do.
I'm all in for murdering Ares regardless
Disassembling is intuitive and comes with the knowledge of assembling, but the opposite is not true.
True, but still we'll discuss it at the leadership meeting, and our track record for planning multi-meeting things is poor.
Would it help if the remaining complex parts for the new shooter were premanufactured?
I was looking around for something that covered the major types of mechanisms I have not seen the past two years, and I found this on AndyMark. Some may have seen it before, but it seems worth sharing as an introductory reference. http://files.andymark.com/ManiupulatorDesign.pdf
A good presentation overall but I disagree with his recommendation against scissor lifts. Their limitations have easy solutions.
@Sean_Williams has joined the channel
bldc's are now legal!!!: https://www.firstinspires.org/robotics/frc/blog/2018-beta-teams-brushless-game-specific-data
*Thread Reply:* lower rpm than I would have predicted.. Interested to hear others' thoughts on these specs:
*Thread Reply:* Much better efficiency than comparable brushed motors from the approved list and nice low speed operation but very bulky for the power or torque.
Sharing this thread for two reasons: 1) some intriguing new strong, lightweight construction products are introduced and 2) there is an interesting conversation about how a 6 miniCIM single speed has some major advantages over alternatives - this is an option that can readily be used with a kitbot & might be worth a look. https://www.chiefdelphi.com/forums/showthread.php?threadid=160093
A file, which can't be shown because your team is past the free storage limit, was commented on.
@Br1an_McK1nnon has joined the channel
So basic resources for what was discussed tonight:
My slideshow: https://docs.google.com/presentation/d/1eJjTbcgL963iIE-crkDxifbasIihyMDhWBfanfzC8v4 Vex robotics motor page: http://motors.vex.com/introduction Chief Delphi: https://www.chiefdelphi.com/forums/portal.php
I’ll be posting a more in-depth article over the weekend on the subject.
@Harrison Gilmore has joined the channel
Looking for help tomorrow after school - - on Monday Dec. 11 at 1:45pm - - Need 1 student to help me carry an FLL game table from Physics store room down to St. Cecilia School. This will only take 15 minutes.
Awesome James. We will meet in Mr. Chee’s room around 1:45 tomorrow. Thanks.
Seems like a quite relevant Behind the Lines episode coming up: when to use COTS vs custom designed/built items. https://www.chiefdelphi.com/forums/showthread.php?threadid=160463
Good thread on pros/cons of including a belly pan in robot design. Electronics mounting / space efficiency / structural stability seem to be key strengths. https://www.chiefdelphi.com/forums/showthread.php?threadid=160489
Excellent new resource just shared: https://www.chiefdelphi.com/forums/showthread.php?threadid=160602
Nice - I really like slides 35-36... We should consider using this table for prekickoff
*Thread Reply:* I agree. These tables are simple but can covey a lot of information. Especially if all our sub teams use the same format.
One last note to the engineering team. The above link that Chris found has a lot of slides (and I mean a lot!) but it is packed with good information and good engineering practices throughout. Also, take a look at some of the close-up photos of their previous robots - their mechanical construction is beautiful.
Very well done set of test data shared concerning 4 CIM vs. 6 CIM vs. 6 miniCIM vs. 6 775pro vs. 8 775pro drivetrains. It's a lot to look through, but I think the following statement from a recent post is a pretty good summary of applicable results: "4 CIMs have been good enough to run fully-weighted robots for a decade now, and they're still good enough moving forward. Teams who use different types or quantities of motors are optimizing for sprint time (8x775, 6xMiniCIM, or 6xCIM are better), weight (6x775 or 8x775 are better), or thermal buildup during finals (6 MiniCIMs are better)." Of course, with 6 CIMs or 8 775pros, special measures must be taken to avoid brown out failures. Also, the tests were all done with a 2-speed transmission (though it is COTS). On the topic of 2-speeds, if the programming team ends up adopting some/all of 254's drivetrain code, then I suspect there is auto-shifting software in there that could be used if the team is interested in trying a 2-speed now or in the future.
Here's the thread with the paper / test results: https://www.chiefdelphi.com/forums/showthread.php?t=160387
@chrisrin You're correct that 254's codebase includes auto-shifting, but it's not exactly a plug-n-play type of thing to get working, so we should carefully evaluate the benefits of such a system before we commit to it.
Here’s a link to buy FRC Game cube covers if anyone is interested. https://www.amazon.com/Official-2018-Game-Piece-Cover/dp/B078GBY8LX/ref=sr_1_1?ie=UTF8&qid=1515256295&sr=8-1&keywords=FIRST+robotics+power+cube
Here is a great overview of "hobby" servos to give some background on their capabilities. I recommend watching this to see where we can apply them in our mechanisms. They are small, inexpensive, and can be very precise -- just right for fine, detailed motion control applications. https://youtu.be/iH9_xtulyws
Thanks Riyadth and Katie. Katie, I have ordered 10 Game piece cover.
When we get to engineering modules, we might be able to look at this year’s FTC robots because they also had to lift cubes.
I think our standard is 6-inch wheels, so we're probably fine... but, depending on wheel size & how wheels are configured with chassis, folks have pointed out the risk of beaching / high centering on the climbing ramp corners. Since chassis work is coming up, seems good to share: https://www.chiefdelphi.com/forums/showthread.php?threadid=161090
Shows many interesting grabbers and a very unique interpretation of the climber rule where a helper elevates two teammates
Apologies for the headbanger backing track
High centering on ramps is not a function of wheel diameter, just wheel spacing and ground clearance. Ground clearance is 2" maximum from Rule R24 and Figure 8-6. It could be less with sloppy construction.
@Ethan Rininger: best “climb on me” ramp from 2007 evidently: https://www.chiefdelphi.com/forums/showthread.php?threadid=161021
See post 7 if we end up looking at a COTS elevator component: https://www.chiefdelphi.com/forums/showthread.php?threadid=161189
Not sure whether to put this in engineering or programming. This CD thread is talking about how to maximize elevator speed via controls tech. The 4th post mentions using a PID on Talons, which I believe we already use (with drivetrain?), but also Motion Magic and Motion Profiling. Anyway, given elevator direction is likely, maximizing lift speed while sustaining control seems like a timely topic. https://www.chiefdelphi.com/forums/showthread.php?threadid=161185
*Thread Reply:* (but that's good to know)
Ri3d Indiana’s ramp design: https://mobile.twitter.com/Ri3DIndiana/status/950440258608517125/photo/1
*Thread Reply:* interesting - seems to suggest a powerless version of the park+double-"climb". Specifically if going up the ramp causes bumpers to exceed the 12 in limit, then no lifting would be required.
If the team does decide to proceed with placing cubes accurately, we will need some lateral capability to do fine adjustments quickly. Given mecanum wheels seem to be a no go, another approach could be to replicate a capability that many forklifts have, called a sideshifter, which allows the operator to move the tines or arms laterally for easier and quicker placement of the load without repositioning the forklift.
I think would also be relatively easy to integrate into any design.
I have seen some interesting mechanisms recently (not much on FRC bots) that use ball bearing drawer slides for linear guides. It seems that we could use some of those to mount our mechanism to the robot base and get reliable side-to-side motion capability.
If anyone is curious on why scissor lifts are not more common, or why the experienced students are hesitant of them https://www.chiefdelphi.com/forums/showthread.php?t=132364&page=2&highlight=Scissor+lift
Here is a well design scissor lift.https://www.youtube.com/watch?v=jFwkC_s2BAQ&feature=youtu.be&t=53s&disable_polymer=true
*Thread Reply:* I was just about to post that one. I am finding examples of successfully used high-reaching scissor lifts. I think the warnings may be in the context of teams running into problems by not designing/manufacturing carefully enough. I actually think if the compactness of a scissor lift (when down) would allow other things to be built (shooter on top) without top heaviness when running around on the field, then it could be pretty cool.
Another scissor lift from the past: https://www.youtube.com/watch?v=FWHihn28gxA
And check out these monstrosities from 2000 - one of them is a scissor lift, but there are other designs as well. If pictures from 2000 can be found, it might be a good year to look at closer for ideas: https://www.youtube.com/watch?v=YCcBXMrR8DY
Maybe we should remove the intake from ARIES to prototpye our intake on Sun. Someone please get Aries off the shelf.
Snow Problem's scissors lift prototype is too crude to use as an example for value judgements. Our prototype is made of suitably sized pieces of wood, not 2x4's.
*Thread Reply:* I wasn't using the video to knock on the scissor lift option; I just thought it was a good walkthrough of lots of different prototype options with good dialog. One of the students even made a statement similar to yours about elevator lifts ("we know elevators work - we don't need to prototype one"...)
I believe Grant's design has merit and deserve's more attention. Below is his original drawing. The link below is to an FRC robot that used a similar design/system. Grant's counter balance design could accelerate the arm up even more rapidly with little motor force. An elevator system could work in place of the telescoping arm. I think it is worth prototyping.
Why prototype it. Clearly it can work. The time spent prototyping would be done better working out the details if that is the mechanism the team wants to use.
*Thread Reply:* Yeah. I think having a ramp could make us very useful at lower competitions ESPECIALLY if we can then get 3 climbs without using levitate. If this were last year, i wouldn’t say lifting 360lbs was a feasible option, but this year there is no limit on the number of CIMs we can use.
This is the ramp bot Harrison and I looked at from 2007.
Interesting ramp idea - but it looks like they had to sacrifice all other mechanisms (from what I could see in the video, not sure).
Regarding the Monkey Wrenches' robot design above, it looks like they were successful that year: "Robotics Team 2016 was very successful at both their regional competitions in Trenton and Washington, DC. They were awarded the prestigious New Jersey Regional Chairman’s Award as well as the Judges Award in Washington, D.C. ...their great accomplishments have launched them to the International Championships, which will be held in St. Louis, April 2011."
The above video also provides a look at vertical elevators and how they compare in competition.
If we're talking ramps it might be good to look at mobility ramps to get ideas since wheelchairs have a roughly similar size, weight, and center of gravity to robots, and the height to climb up to a van or porch are also roughly similar to our climbing task. The middle hinging ones seem interesting from a pre-endgame space perspective. https://www.discountramps.com/wheelchair-ramps/c/3100/pgsize/All/
Way less complicated than the side ramps I was thinking of. An idea worth stealing. I would fill in the rectangular space with polycarbonate or something like it for carrying sponsors' names and for deflecting cubes thrown up by low shooter bots.
It seems like their climbing system took very minimal space on their robot. Is it reasonable to assume that there is enough room for a cubes manipulator on the rest of the bot?
The only problem is that the rope is going at a diagonal being in the way of the cube lifter
So if we were we would need to make a small compact lifter
The second video shows a space that they think might hold a cube handling system. But they only worked on the climber, and didn't design the robot to manipulate cubes.
I think we should take that idea (ground level plates) rather than taking the whole mechanism. I think this does prove that this system can lift 3 robots though which is (in my opinion) very important. Why? Because it means we don’t HAVE to waste 3 cubes on Levitate so we (or our alliance) can put those on switches and on the scale, or devote them to other power ups.
Plus possible alliance if we don't make it to playoffs
Yeah. Furthermore, there is no longer a limit on the number of CIM motors, so we could use a dual CIM climber, meaning we won’t be nearly as slow as we were last year (potentially).
Does anyone have a picture of the prototype scissor arm?
118 released their "everybot" - a fast cycling exchange/switch placing bot. Check out how the intake can take cubes in any orientation. https://www.youtube.com/watch?v=RQNCeHsOeJE&feature=youtu.be
Here is the list of steps and requirements for the climber. Feel free to add comments. https://docs.google.com/spreadsheets/d/16UsQbuSxHZaBjMxUQS0OeBaFg87_fXKBlKat4cA1_Hs
I added three new channels for each of the modules in slack today. All mechanics should join the channel of the sub team team that they are on, and I would strongly recommend joining the other ones for communication purposes.
FYI I have put together the basics of the scissor lift and attached it to a chassis in CAD
*Thread Reply:* Is that in the cad file system?
*Thread Reply:* I can send a screenshot if you want
Currently what the space allocations look like. 8” x 27.5” for scissor (blue) 20.5” (really the entire front of the robot right now) x 4.5” (red) 2 (6”x12.5”) space for Climbing ? I still don’t get the set up right now. (interior grey boxes)
Battery goes in the back of the robot next to the scissor. (up being front in the image) There looks like a possible interference with the climbing, but the space is supposed to be mostly empty space?
As well, I would like Dimensioned Drawings for each of the modules by the end of the meeting, and the beginnings of a CAD file. (The CAD file is to be completed by the beginning of the meeting on Friday ideally).
At the very least, show me what you’re talking about in a large, detailed drawing, so I can start sorting issues out tomorrow, rather than when the CAD’s are done.
Kenneth, I have an ask: Could we get two perspective views (maybe looking down from back left and looking down from front right) instead of just the top down? Reason: systems will probably need to share space from a top-down perspective. For example, the climbing winch may need to be above the intake - looking at what you have so far, it seems likely.
I haven’t really done height allocations, mostly due to the robot starting height can be 55in, and I was having a hard time placing the climbing volume, due to them being directly intergraded with the scissor lift. As well, this is the first I think I heard of the winch being located above the intake, as what I heard at the meeting it was going to be under the scissor lift.
That’s why I was also waiting for the drawings of the modules, so I can start seeing how everything is going to fit together, as the scissor lift was the only thing I have a semi-understanding of how it is going to go together and placed on the robot.
@Kenneth Wiersema gentle reminder to keep camera in mind. we have 4 years of experience that tells me it can’t be an after thought that we can decide the bag day. thanks!
I currently have no idea where I can even put it, as if it needs to as close to the center of the robot as possible, but still not getting in the way of the intake, which I haven’t seen a solid design for yet, and it’s not in cad yet. And it can’t go on the scissor lift so, there are not a lot of places left. I need Intake designs before placing it.
*Thread Reply:* How will driver/operator aim where to place cube on scale without a camera on the lift? I was assuming a cable would be run up to a camera on the lift for the purpose of aiming. Let's discuss.
*Thread Reply:* Unless we have a separate way to mount a camera high
*Thread Reply:* This to my understand was for vision not for driver use. The camera that you are discussing would be for driver use only, but I got confirmation from Darwin that they don’t want it on the scissor lift.
*Thread Reply:* ah, ok, makes sense - please do plan on a camera on the lift though. Without it, I don't see how we'll achieve precision that would be better than a low shooter.
*Thread Reply:* Following up: I played around in Synthesis & from that I do believe having a high camera view will be super helpful - we will perform better at placing if we have one IMO. Here's a picture: https://1drv.ms/i/s!AkoZXdKPoojXjqN6U_uFUPz_RoafjQ
*Thread Reply:* I think locating it all the way at the back of the lift, somewhat higher than the top of the lift, will be the way to go.
I remember last year there was a way to look at the latest working version of the full robot in Fusion 360 - is that possible this year? The climbing design will be constrained by the lift & intake, so good for us to be able to always look at the latest. thanks
*Thread Reply:* Kenneth or I can show you where to find the most recent file on fusion at today’s meeting
*Thread Reply:* @chrisrin it is under a folder call Spartronics and then a folder called Power Up
We can mount the camera on the scissor lift. Creativity is required.
*Thread Reply:* From working in the simulator, the higher the better. If the top of the scissor lift platform is 40 inches at the start of the match, for example, it'd be good to have the camera at the back behind everything, as close to the 55 inches as we're comfortable. I'm not sure if you saw the screen shot from the simulator - here it is: https://1drv.ms/i/s!AkoZXdKPoojXjqN6U_uFUPz_RoafjQ
This is a link to our inventory sheet for reference. https://docs.google.com/spreadsheets/d/1_bmW_kvP3pyDZnIK-7-0UKK7PyeKFqyp173MM4soqi8
Please make sure @kaedricholt and @jackchapman and @peter_hall is updating. Thanks
Idea concerning the climb with friends dropdown forks... in the rules figure 8-2 indicates chassis sides are not required to be covered by bumpers... only the corners are required. I could see it being advantageous to leave our robot sides uncovered so the forklift platform could wrap tight around the chassis when they are in the lowered position. In fact, a robot shared by Bill B on the climbing channel is set up just like that. Thoughts?
now that I look at the picture, the things on the corners are pretty clever as well for being able to track the robot when other robots or field pieces are obscuring it
*Thread Reply:* we added something like that to our robot 2 years ago after the 1st day of the competition. Through experience, we also learned about bendy pieces extending beyond the frame perimeter
I talked about this to Lucas and, it is a good idea but those kind of bumpers fall off the robot very easily.
Most teams do that because they are easy to build but they are easy to fall off
FYI. We have constant force springs. Maybe we can use for intake. These springs are similiar to a tape measure that rewinds itself.
*Thread Reply:* I'd like to see what we have. They could be used with the arm that connects the grabber to the lift to help counterbalance the weight of the cube. They should be in the relaxed position when the arm is laying back on top of the lift and then under tension when reaching forward and down.
We have some from previous years. We can get 6 more free ones. Please let me know and I will order them. @chrisrin @paulvibrans @Mark Tarlton @brianbonifaci
good thing they only have 2 digits in their team number 🙂
@chrisrin Corner bumpers would require us to completely rebuild the mounting hardware. Essentially we’d be starting from scratch. Also, I’ve seen several teams use them, and they simply don’t work.
@Harper Nalley: I hear that it would require an updated approach & it would be a challenge, but I question the “simply won’t work” assertion. If the “climb with friends” platforms/forks will be more stable, simpler, and possible lighter if butted against the chassis rather than against bumpers, then does it make sense to prioritize avoiding a bumper design challenge over that? I did some research myself last night indicating corner bumpers can be done in a way that they work and don’t fall off. Let’s discuss live next meeting.
Have the bumper attachment points on the chassis been located yet or have any of them been installed? They should be shown on the CAD model if and when they are.
Does the plywood backing on the bumpers have pockets to clear the bolt heads that project from the chassis?
Put another way, does the plywood fit tight to the aluminum sides?
And the locations for the brackets are taped onto our chassis but I don’t know if it is in cad yet
@chrisrin the reason I said that was based off of watching other robots use them.
@Harper Nalley I suggest we stop construction on the bumpers until we finalize the different mechanisms.
Here is how the Scissor Lift works: According to Paul: Two air cylinders working in parallel raise the lift. Air is admitted to the cap ends while the rod ends are open to the atmosphere with no tube connections at all. Two solenoid valves are required; they should not be the spring offset type.
Valve 1 has the pressure input connected to the tank and the A output connected to both cylinder cap ends and the B output plugged. Sending air to the A output raises the scissors and sends air to Valve 2. Sending air to the B output does nothing.
Valve 2 has the pressure input tapped into the tube(s) between the cylinder cap ends and the A output of Valve 1. The A output of Valve 2 is blocked and the B output vents to atmosphere.
To raise the scissor, shift both valves to the A position. To hold the scissor in the up position, shift Valve 1 to B and Valve 2 to A. To drop the scissor, shift both valves to the B position.
A third, small, spring retract air cylinder actuates a toggle on one of lift cylinder rods to stop the scissor at any height. It will not stop the scissor from collapsing. One solenoid valve is required to admit air to the cap end.
Valve 3 has the pressure input connected to the tank and the A output connected to the small cylinder cap end. The B output of Valve 3 is blocked. To stop the scissor at a particular height, shift Valve 3 to A. The toggle will not release to let the scissor rise higher until Valve 3 is shifted to B and the scissor is allowed to drop slightly.
Position indication for the scissor is by a single turn potentiometer mounted at mid-height on the scissor and connected between one outer link and the shaft that is rigidly attached to the inner link. The range of rotation is 123 degrees.
The cylinders have magnetic pistons that can activate switches, if installed on the outside of the cylinder body, that can be used to send a signal to the RoboRio to operate solenoid valves. The switches mount with a band around the cylinder at whatever position where something is supposed to happen. More than one switch can be mounted on a cylinder as long as they do not interfere physically. With two cylinders working together, a switch that otherwise can’t be mounted because another switch is in the way can be mounted on the second cylinder. At this time there is no plan to use these switches. One thing to consider is that trying to stop the cylinder just by closing the air valve may not be successful because the air may continue to expand in the cylinder after the valve is closed, pushing the cylinder farther. This is the case when a Power Cube is released and the weight supported by the scissor is reduced; the scissor will go up. A possible use of these switches would be to shut off the air before the scissors reach full height but with still enough pressure to carry the scissors to their maximum elevation; this will save air.
*Thread Reply:* WOW! Nice set of details, thank you @Cruz_Strom The message is pinned to the channel, and lets keep any discussion on scissor lift design to this thread.
*Thread Reply:* This is a great model for what the other subsystems need to post!
*Thread Reply:* a picture would be worth 1000 words for my brain
*Thread Reply:* What Dana said. +1. I'm a visual learner.
Harvester: The first thing the cube interacts with with the robot is going to be the harvester. The purpose is so that it allows for our grabber to be more accurate when grabbing the cube and reduces alignment time for the driver.
At the beginning of a match, the two arms will be folded in (I wanted to dub it the origami mechanism because it folds… hah) so they fit within the frame perimeter. We’re using a 7 inch pneumatic piston to do this. I’m forgetting on how it’s attached, I will update this eventually and if it’s important, ask me at the meeting tomorrow.
Note: Piston Open - arms close Piston Retract - arms open
For auto, we’re likely going to want a sensor to able to align with/detect a cube (if we’re doing a two cube auto, that is). We thought limit switches might work for this, but some sort of distance detector would be better.
To physically interact with the cube, we have pulleys on each arm of the harvester which will be individually run by bag motors with 10:1 gearboxes.
The cube will be pulled in close to the frame and will theoretically set off a sensor that will either (unsure on which is better): automatically have the grabber come grab it if the sensor says it’s well aligned or will let the driver/mechanism controller know the cube is aligned so they can tell the grabber to get the cube. Undecided, depends on what the driver/mechanism controller want.
Once the cube is aligned, the arms will open and the grabber will grab onto the cube. Timing is going to be interesting here. Especially since we’re going to likely be moving with the cube in the harvester and a quick handling of the cube to the grabber from the harvester may be strategically important. Tweaking involved.
It’ll be important to be able to open up the arms and be able to close them because if we’re being defended against we’re going to want to apply pressure (open piston) to be able to hold onto the cube better, or if we’re moving. It’s a method to be able to hold the cube better. Then, if we have no cube in the harvester, and we want to get a cube off a second stack, we can’t control the bottom cube because that would result in a foul so the harvester needs to close - fast. Driver is going to have to do more work to align with the cube that’s on the second level of the cube stack.
Piston Open - arms open Piston Retract - arms close
Grabber will be rotating up and down from the scissor lift from a winch system (?) that Paul devised. It’s powered by a CIM. Cruz should have more details than me.
It’s powered by a 10 inch pneumatic and is designed to grab the cube the same way time the same way. It should be grabber onto the handles of the box if in the short position, but pneumatics are strong and the grabber arms will also be able to grip if it’s in the tall position. We tested this.
Grabber will lift the cube up to its highest point and open the pneumatic to release the cube. Because of how the grabber is designed with the backplate, the cube will slide off the backplate if fully lifted.
There’s not a lot of sensor consideration here, but perhaps a pressure sensor to make sure the cube is well grabbed. Can be discussed further.
This should be a good summary - I can further explain details if they're unclear or need explanation.
How climber will work:
Quick question: Is there a constraint that absolutely blocks us from climbing with the hook on the back / opposite side of the lift from the grabber? I ask because there's nothing on that side of the robot and a lot of stuff on the "front". How high can the the circled spot go with the fully extended?
I think you can mount there but it will be much closer to the front of the robot when fully extended
*Thread Reply:* Right... Probably more than 8 1/4" away from the bumper edge?
*Thread Reply:* There should be a cad with the scissor funny extended where you could look
The pivot point where the flipper attaches to the top of the scissor is 9.3 inches back from the bumper line and 0.8 inches above the top of the rung when the scissor is extended to full height. The corresponding end of the scissor that you are considering for attaching the hook is 22.2 inches back from the rear bumper line and 2.5 inches below the top of the rung when the scissor is extended to full height. We can put a hook or hooks where you would like if we put them on a second flipper so the hook(s) do not hang over the back of the robot when the scissor is all of the way down. This means adding a second flipper with some kind of drive. This would put the crosshead guides on the end opposite from the gatherer, which is good. Getting the geometry to remain satisfactory as the scissor collapses during the climb is key.
Thanks @paul_vibrans. My motive of considering the back for climbing was simplification (it's out of the way) & minimizing risk to the highly important grabber. What you described seems like it would add considerable complication to the scissor lift, and as far as geometry the back is a worse spot for the hook to catch the rung as well. Partway up the flipper arm (i.e. existing plan) seems like it will be a nearly perfect place for the hook given the measurements you shared. Best risk mitigation is likely to not place the hook any further up the flipper arm than necessary so there is a bit of a space buffer. So let's stay the course with the hook on the existing arm unless others would like discuss further.
We need to put the grabber in the 3-D model to make a final judgement
Here's the scissor lift more or less extended. The climbing hooks cannot be placed on the back of the scissor lift, so I agree that they should be kept where they are, (under the grabber) however there needs to be some talking with the grabber group to sort out the placement of the hooks, and to potentially make the grabber arms longer
@chrisrin commented on @Kenneth Wiersema’s file Scissor Extended: one thing that comes to mind is possibly adding an extension to the end of the hook to help avoid catching the grabber on the rung and damaging it - we should definitely have a spare grabber assembled if we locate the look there because the action of catching the hook is halfway across the field and an accident is likely to happen sometime - binoculars could help maybe? 🙂
@Ted Larson Freeman has joined the channel
I did some testing of the x-carve using a 1/4" carbide endmill. The results are very encouraging. I'll post the details later, but the attached video shows 1" holes being cut in thick walled aluminum.
It sliced through sheet stock easily as well. It was less than a minute to cut a simple bracket with a single bearing hole. The other surprise was it wasn't very noisy when it was cutting properly. The next step will be to have fusion 360 generate the g code. This test was done using Easel only. Drilling small holes is still pretty painful. The small mills we have don't cut nearly so well. With recommended speeds and feeds it's 5 minutes per hole for 3/16" dia. I think we should try using short drill bits instead if we can find ones that fit the chuck on the router.
I'd want to do some research on that, as if the cnc tries to cut how it typically would, we would be breaking a drill bit.
Right, that's why I want to use Fusion for g code generation. It offers drilling as an explicit type of cnc operation. It can generate paths that are exclusively plunge cuts with no lateral movements. You specify drill bit and diameter as the cutter.
Okay, I haven’t looked much into the Fusion cnc interface, but if we can do we should try it.
You can also use the v carve program to generate g code
Yeah, I looked at it this afternoon. The first problem I ran into is the file export/import hassles. It would be nice if we could stay in fusion all the way to gcode generation. Fusion seems to support a lot of milling techniques but the user is responsible for figuring out how to go about making the part. My gut feel is that it's with the effort to figure it out.
Okay, I think we might want to table this til a little later in the season when there’s not as much work to be done, depending on when we get the robot done. But I’d like to keep this in mind for next year
Here’s the inspection checklist for this year, please take some time to look it over https://firstfrc.blob.core.windows.net/frc2018/Manual/2018FRCInspectionChecklist.pdf
*Thread Reply:* @ronanbennett @noahmartin ^^^ pls review from programming perspective
*Thread Reply:* @binnur the only programming considerations I found were making sure the roborio and driver station are up to date, and the team number is in the driver station correctly.
*Thread Reply:* Yup - that pretty much covers it. for our internal checklist, we also want to make sure we validate the latest versions of the fw as well. thanks
Kenneth is asking nicely, but really everyone who is contributing to the build of this robot should read the inspection checklist, and get some attention on any issues that may result in inspection problems. If you're working on a subsystem, find the checklist items that address your design, and if you think there might be an issue then tell your team lead or a mentor. Let's try to pass inspection on the first try!
Back on 1/20 I shared a full inspection video done by a robot inspector on one of the RI3D bots, in case that is helpful
Thanks Mark for the effort on the Carver, that’s what we had in mind to begin with for capabilities. The climbing team could carve a hook if the CAD file is complete.
@Kenneth Wiersema: i see there are longer picam cables in lengths 100 and 200 cm... Preference?
100 cm is more than enough, I don't need 2 m of cable, something shorter would be nice too, maybe triple the current cable length would be best
How I'm thinking right now, that should be good, so don't worry about it
so to confirm, you don't want me to buy longer ones?
Yes, I don't want you buying longer ones now, I'll work around it right now
I think we’re ok on this, but posting anyway: https://www.chiefdelphi.com/forums/showthread.php?threadid=162478
We don’t need to worry about it, the chassis is 27.5 as recommended, so we don’t have to worry about the minor protrusions fitting in that volume. And they shouldn’t cause a problem with the starting configuration.
Read it a bit further, and we might want to check bolt heads, but it sounds like that most teams were having issues with mounting the bumpers more than the stuff sticking out of the chassis
Next FUN episode on Inspections: https://www.chiefdelphi.com/forums/showthread.php?threadid=162600
I came across a recommendation for this cutting fluid for aluminum that helps avoid breakage when tapping holes. Anybody have thoughts about whether this is worth getting? http://www.tapmagic.com/product/2/tap-magic-aluminum
my notes from first testing:
air leaks are a real issue. The three that we found were fixed but my sense is that was a testing bandaid.
the amount of time to fill the air tanks is substantial (minutes). Programming needs to provide team with a means to fill the tanks while in queue. (@declan_freemangleason proposed a new autonomous method). The testmode menu could also be applied.
the limit switch mounts for the flipper are mission critical, we need to make sure they are locked down. It's possible programming can mitigate failure by establishing current limits for this motor.
the scissor was very fast to get to the top with no load, less so with a cube. We haven't tested the key capability of stopping the scissor at various setpoints.
the entire machine feels dangerous. The battery access is perhaps the worst offender. Probably need to put some "danger" tape on access points that represent risk to limbs. The harvester's flipper in and out are rather intense. The scissor has lots of space to catch things. @Charlotte found a torque wrench lying unattended in the chassis.
@peter_hall reversed a couple of tubing channels to obtain correct "rest" behavior. Its possible that we should do this also with the harvester. I'm not certain if peter was keeping notes regarding the "official" tubing diagram. As changes are made an official diagram should be updated.
we need to get the IR sensor wired into the AnalogPort 2
it would be great if the pneumatics & electronics spreadsheet matched the diagram that peter worked off to build-out the first system. I believe @ronan_bennett was updating it live last night, but we need to make sure that as things change, we are all on the same page.
It is extremely critical that the pneumatics/electronics/control spreadsheet be updated with all information before bag day, as we will not be able to make a duplicate robot without it. I believe that we should add additional information and diagrams to clarify plumbing subtleties. @peter_hall please coordinate your team to gather the information.
*Thread Reply:* We can get that done this evening
The flipper needs a valve in the air line to reduce speed.
By flipper do you mean grabber? (The flipper is run by a motor)
I believe @brian_bonifaci is taking about the harvester
It was referred to by Dana above as "harvester flipper",
By flipper I usually mean the articulator (wrist) part of the grabber. I also used (incorrectly) flipper in the context of the harvester. The hugging arms could be a little gentler, but this may not be a priority. Sorry for my flipper confusions.
For anyone that saw Chris's post earlier about concerns about our frame perimeter, the team update 11 resolved that issue by allowing the small protrusions to be outside the 28" by 33" envelope this year, as how the rules has been previously made this illegal. We really didn't have to worry about it on our end, with the chassis's 27.5 by 32.3 outside perimeter, but it is something that should be kept in mind for previous years, as something like this could fowl us up. Team Update 11 details the change and the reasons for it. https://firstfrc.blob.core.windows.net/frc2018/Manual/TeamUpdates/TeamUpdate11.pdf
anyone interested in diving into the X-Carve / CNC may want to take advantage of this free slide rule offer. http://www.niagaracutter.com/speed-feed-slide Slide rules are handy tools for doing table lookups. This one in particular, can be used to determine cutting parameters based on router speeds, cutter diameter, material being cut, and the number of cutting flutes on the tool. To get the tool, signup at the link above. I can show people how to use it if interested.
This is my list of what we need to do at today’s meeting. Please add in anything I missed.
Mount camera on harvester Secure hooks in starting position Make sure the flipper is fully functioning Cut out the top of the second harvester Bling??? Mock inspection Single cable Hardened steel rod on linear actuator New bottom pulley
*Thread Reply:* The grabber wasn't picking up cubes on edge last time. The plate was interfering. Has that been resolved?
*Thread Reply:* No, @whobbs1496 should we cut down the plate?? It sounds like it’s probably worth our time.
*Thread Reply:* I haven’t cut carbon fiber myself nor have seen it done so I don’t know the time frame on that
*Thread Reply:* I know we cut down one of the plates but we may need to cut a little more off
*Thread Reply:* I think there are more important things we need to do first
We should change to single cables on the competition robot's flipper and put a hardened guide rod on the linear actuator.
Does changing to a single cable require the pulleys to be changed again?
If engineering is considering changes to the robot, please focus on improving speed. As the robot is now, in my opinion (and from observation during testing), the flipper and scissor lift are not fast enough. Additionally, the harvester cannot eject far enough to work well in the exchange (but cube cycling to the switch and scale are higher priority).
*Thread Reply:* can we speed up the motors for harvester eject? Increasing the speed by 25% might be a good test for now...
*Thread Reply:* If that's not enough, we can try to fit larger wheels. Robot perimeter dimensions will limit the max wheel size.
*Thread Reply:* Harvester eject is at max speed
*Thread Reply:* looking at line 80,81 of Harvester.java, i see that max output is currently set to +- .75... Bumping that to 1 should produce %25 more power.
That’s not something that can be easily addressed right now, especially with the current configuration of the robot, as I don’t think we can do those changes even with the mechanics getting all 6 hours of unbag time to do it, at least for Mt. Vernon. Depending on usage of the second robot there might be some solution we can work out on it before Glacier Peak, but I’m not confident about that.
Changing from double to single cables does not require different pulleys. It does require a change of parts on the linear actuator.
Ok, it should be first priority once the robot is un bagged is getting the linear actuator replaced and then getting the pulley system redone with the single cable
Here is the link to the packing list for competitions. https://docs.google.com/spreadsheets/d/1xp6Auc7aDwEJIID_ZGfxxbgi8nDbaHzCZCyws8bDpyE/edit?usp=sharing
X-Carve update. I installed the new X beam and the new Z slide. The Z movements are way out of calibration and X-Carve has changed how they mount the rollers to the frame pieces. When I upgraded the X Axis beam, I followed the new instructions. I would like to remount the slide rollers on the Y-Axis to match but I ran out of Nylock nuts. I'll try to get in on Tuesday afternoon to address the remaining problems and test it all out.
*Thread Reply:* Were you proposing extending the telescoping pole during the match? It has to fit within the 55" max height at the start of the match. We could attach a lightweight, fixed height pole to the back of the scissor so that it goes up as the scissor lifts.
*Thread Reply:* sounds like Paul also has an idea for attaching to the center of the lift - overall I think there's an opportunity for a high cam & I do think with practice that could help Will and James avoid misses when trying to place on the scale. Hard to say how much practice alone would help vs. having a camera, but you can bet the majority of elite teams have high cameras and practice using them
After seeing the time we repeatedly spend tuning the latex tubing springs, I thought to myself there must be products that allow a more efficient process (I.e. without needing knots in the tubing). I found this as an interesting start. https://www.spearitco.com/ https://www.easierliving.com/exercise-tubing-by-rep-band.html?utm_source=bing&utm_medium=cpc&utm_campaign=PLA%20-%20Shopping&utm_term=4584551171165519&utm_content=All%20Products
Theraband is a well known provider of bands. A study was conducted on the material properties of the bands. one finding is that after pre-stretching, the force produced was less than before.. BUT, pre-stretching as few as 20 times will stabilize its performance. If we take this into account, we should be able to reduce the number of times we re-do the bands
https://academic.oup.com/ptj/article/81/8/1437/2857666 the link to the theraband study
Also, the bands produce more force during "loading" than "unloading". This explains why the lift may struggle to go up (bands are unloading) and then get stuck on the way down (loading).
@Mark Tarlton: that is super useful - thanks. New task for underclassmen: pre-stretch all latex tubing
Theraband is probably designed to have a lot of hysteresis. Spear gun rubber probably does not because energy release is on contraction.
@chrisrin commented on @coachchee’s file Online FRC resources for engineering and mechanics subteam.: Engineering and mechanics resources shared by coach early this season: http://www.firstinspires.org/resource-library/frc/mechanical-resources
I've heard several people are interested in swerve drives (2910's success this year may have something to do with that, though a LOT of that success was from excellent, well-practiced driving 🙂).
Here's a really good intro to swerve drive design (link to presentation within Chief Delphi post): https://www.chiefdelphi.com/forums/showthread.php?threadid=165331 ENJOY!
*Thread Reply:* https://www.youtube.com/watch?v=FLnUZBHBczM
2910 swerve resources: https://www.chiefdelphi.com/forums/showthread.php?threadid=159376
CAD for swerve in "parasolid" format. https://github.com/woolfepr/Swerve-MK1
@channel We still have spots open for the BARN class, please fill out the survey to say whether you are going https://docs.google.com/forms/d/e/1FAIpQLSedWLGtDQLSnP7B3P8E9-0Wm4eUxX7ucnet16Lk68qxgCS19Q/viewform?usp=sf_link
Hey, I was thinking the last mainstream shooting game was 2016, and we're due for another one in 2019. You could say 2017 had shooting (WE had a shooter), but so many teams skipped fuel that I would not say it was mainstream. Power Up had shooting, but it was quite limited.
So let's say there's a good chance shooting will be part of the upcoming game. As interesting as swerve drives are, I think vision assisted turret shooters are as or more cool. Seeing robots driving across the field, while using vision automation to move their turret automatically & make shots, is amazing.
If anyone else is interested in this, IRS created one in 2012 for Rebound Rumble, and they cover it in their engineering notebook from that year here: team1318.org/resources/ IRS did sort of OK that year at competitions, but their engineering notebook is really well done. Actually, all of the engineering notebooks are worth reading. Enjoy!
@chrisrin I could bring up the idea of vision-assisted 'shooting' in <#CAAE87VHV|atlas-restoration>. After we hit the deadline for 4th of July parade we are looking to add more features to Atlas, and that would be a good training exercise.
@Darwin Clark It might be fun to get a vest with a distinctive reflective tape pattern detectable by a vision system, and then have the robot spin around to find the person wearing the vest & toss him/her the ball. Or demonstrate the robot picking the vest wearer from a small group formed into an arc.
@chrisrin Yeah, we we thinking a smaller-scale application of that, such as a reflective sign, and passing that around the crowd. I do think the 'picking' from the crowd would be a fun exercise to do.
*Thread Reply:* Sounds good - start simple, and then you could go in lots of directions from there. Maybe in a couple years you might have 3 different signs on lanyards (an X, a bullseye, and a smiley face, for example), and with a microphone integrated you could get Atlas to understand and execute commands. "Atlas, toss the ball to the bullseye"... And then there would be the opportunity to explain each element of that solution.
Paul is offering to teach a class on making circular objects with bearing in the middle. The class is over 4 Mondays or Fridays starting in the first week of June. Each class only has two students with potentially one mentor overseeing the process. The class has a materials fee of $20. To sign up please email Paul and deliver the permission slip and fee at the first class. Please read through the document to find more details.
The two spots in the Friday session are still available. Both spots must be taken or there will be no Friday session. The Monday session is filled.
The last chance to sign up is 10 AM, Thursday, May 31 for the Friday session that will take place from 3:45 to 5:45 PM on June 1, 8, 15 and 22.
*Thread Reply:* Paul: I'm planning to sign up for the Friday class, just haven't sent an email to you yet. Sorry!
Interesting breakdown of 3D print materials. Looking across it all, polycarbonate seems the most intriguing to me for FRC applications, though it requires more printer features for reliable prints than other materials. https://www.simplify3d.com/support/materials-guide/properties-table/?highlight=polycarbonate
A while back, I decided to learn some Fusion 360 fundamentals. I found Autodesk's own beginner tutorial videos to be mystifyingly poor, and so I looked around for other options. Paul McWhorter's series called "Learn Fusion 360 or Die Trying" worked well for me. The video production is imperfect, but the sequencing and the pace of the lessons is very well done in my opinion. By the time you get through the dozen or so lessons, you have some skills. Here's a link to the first lesson in case anyone's interested in starting to pick up F360 this summer: https://www.youtube.com/watch?v=y5tp4QXciK4
@chrisrin Do you think it would be a good offseason project to make videos for Fusion 360? Perhaps focusing more on the aspects of Fusion that are more applicable to robotics?
*Thread Reply:* Good idea. Learning to do instructional videos like that, including recording presenter video/audio, recording on-screen video, etc. is a great skill. I think a quick win might also be to just find a bunch more existing videos that teach relevant skills.
*Thread Reply:* True, but I have only found robotics centred videos for Inventor, none for Fusion.
*Thread Reply:* I have screen recording software on my computer and I could try to make a video and see how it goes.
*Thread Reply:* I was going to write a series of topics on how I want CAD done during the summer. Videos might be good for basic skills but my primary issue is getting people to CAD properly and efficiently. I’m probably going to be learning a few things from BARN over the summer, so there might be changes to my ideas. Also robotics applications are simple modeling, assemblies and creating drawings, which all fall into the generic skills catagory
*Thread Reply:* @Kenneth Wiersema maybe you could start with an outline of the approach you want the team to align on, and for each step of the approach indicate the skills (e.g. 2D drawings with constraints, using parameters perhaps) needed to execute. And then the team can find videos teaching those skills OR if none can be found, then the team could create its own. And it sounds like @Harper Nalley is interested in contributing to that
*Thread Reply:* Regarding what to teach, here's a Behind the Lines episode on CAD that discusses whether to teach assemblies or drawings. I've (I think) linked to the relevant Q&A topic. It seems to me that assemblies may be the focus when parts are designed (or pulled in from COTS), but every team will need at least a couple people who know the software at the 2D drawing / constraints level as well, and that series I shared a few days ago really does a nice job of introducing the 2D side of things & parametric design. Video link I mentioned: https://youtu.be/cbB8qGlLKGU?list=PLIY-TB1MAu-X9ZcNqt-ot6_JM2Z02zZ6L&t=4161
Here's a new set of videos on CAM with CNC Routers created by a student from team 3647 (Aluminum Falcons). The team uses HSMWorks with Solidworks for CAM, but I've heard the CAM side of Fusion 360 is actually a slightly more robust version of the same software. Since there will be some CNC classes (though they'll be with a mill rather than a router) at BARN later this summer, this seems good to share: https://www.chiefdelphi.com/forums/showthread.php?threadid=165777
A great article on engineering technique.
I ran across this mechanical linkage design/simulation software this evening - seems pretty neat! http://blog.rectorsquid.com/linkage-mechanism-designer-and-simulator/
*Thread Reply:* Could be used to figure out dimensions and geometry given constraints in the rules (e.g. designing a robot arm that follows the Power-Up rule of staying within 16" of robot perimeter)
Hi, I'm not sure if there is interest, but I noticed there is an established CAD-athon for FRC folks from August 2nd 6pm to August 5th 8pm. Teams of 2 to 3 people participate - mentors & students welcome. Individuals can also sign up, in which case they'll be partnered with someone by the organizers. Here's a link to more information: https://www.chiefdelphi.com/forums/showthread.php?threadid=166041
Here's a software-agnostic presentation on CAD / 3D Model & Drawing Fundamentals from team 254. It seems well done & it even includes worksheet-type exercises for skills building. I think the points made about the importance of 2D drawings in addition to 3D and the suggestion at the end of the presentation that a top-down design approach works better in FRC than a bottoms-up approach seem spot on. Top-down ~ start with rough whole robot design concept and iteratively update/refine it as components are refined. Bottoms-up ~ refine components and then figure out how to integrate them. Here's the link - hope some of you like it: https://www.team254.com/documents/cad-fundamentals/
Thanks for finding this, the 2d modeling section covers a lot of the material taught in technical graphics, I would really recommend reading if you haven't taken technical graphics yet
It's a good overview, but for 2d drawings it comes down to readability in the end. You really don't have to know the rules for dimension, but it needs to be readable by anyone, and enough dimensions should be included for any other necessary ones to be found. It does do a good job of describing basics, but not quite the main purpose for it.
254 released their tech binder and build blog. The tech binder is an enlightening read. Several PNW teams like IRS and Shockwave create similar docs after each season to record what they did & why. Is this something our team might consider? https://www.chiefdelphi.com/forums/showthread.php?threadid=166176
I’m trying to create one of these; I have a basic outline for.
*Thread Reply:* Thanks Lucas! I'm wondering if there isn't a way to link engineering notebooks created by students taking robotics as a class to the effort of creating something like this each season. Future Spartronics teams will benefit a lot from having a written-down reference of what past teams did. Otherwise, mentor memory is all we have, and (speaking for myself at least) I'm not sure how much will be retained that way.
*Thread Reply:* I was thinking about compiling it from the leadership team’s notebooks. I’ll send you the outline I made.
*Thread Reply:* THE NOTEBOOK SHOULD COVER
WHAT What module did you do? Include a basic drawing and/or printed out isometric CAD view
WHAT ELSE? What were the other ideas you played around with? Include a basic drawing and/or printed out isometric CAD view (this only applies if a CAD model already exists AND is detailed enough to use as a visual reference) Also go over why you DIDN’T choose the other design(s). Try to include the pros and cons of each design and why, in spite of the pros, it wasn’t chosen.
WHY This is similar to ‘WHAT ELSE’. You should go into why you chose the design you went with. Explain the pros and cons and why the pros outweighed the cons.
DESIGN This should include full CAD drawings of the final design and any paper and/or CAD drawings of earlier iterations. Explain what changed and why.
MATERIALS This should cover what materials you used, why, and where they came from.
IMPROVEMENTS This should cover two parts: what improvements that were made through the competition season (if any) including CAD and/or hand drawings, why these improvements were made, and how. The second part should cover redesigns and/or semi-major to major improvements that were planned but ended up being scrapped. Also, cover why they were scrapped.
TAKEAWAY The final section should cover what went well, what went poorly, how you should have done things differently, and why.
They fixed their robot with a hair drier
Rev robotics announced some interesting products: https://www.chiefdelphi.com/forums/showthread.php?threadid=160494
I think the ultrahex shaft with the 5mm hex inside bore could be great for prototyping things like intakes and shooters. A drill + 5mm hex bit + a length of the ultrahex shaft seems like a quick and easy way to power a wheel.
And the 1" linear motion system seems like a good way to elevate something lightweight (like a high camera 🙂 or maybe a climbing winch hook)
The other stuff seems pretty cool too (like the LED bling blinky controller)
Chief delphi thread on drilling bearing holes with a drill press. https://www.chiefdelphi.com/forums/showthread.php?t=166372 Some of these might be worth looking into
The team should consider getting a subscription to "G-Wizard" from www.cnccookbook.com to support our CNC work. This is a tool that helps select the right feeds and speeds for CNC, milling, and lathe work. You build up a tool library with all the mills, bits, cutters, etc. Then when you have work to do, you select the machine you're working with, the specific cutting tool, the material you're working with, and the quality of finish you're looking for. It will provide a set of recommended feeds and speeds plus an indication of how close to the 'edge of the envelope' you're running. You can then make adjustments interactively to zero in on the cutting settings. I did a 30 day free trial over the summer and thought it was pretty useful.
@Kenneth Wiersema -- Regarding the ownership of the Spartronics project in Fusion 360, I came across a post on changing project admins. https://forums.autodesk.com/t5/fusion-team-forum/how-do-i-change-or-add-a-project-administrator/td-p/6533906 It sounds like we can request help from Autodesk to get the admin switched. I suggest adding Coach as one of the admins plus one or more students. Then we can maintain the project over multiple seasons.
Doesn't apply to us, I found that or something similar, and that's using a team hub system, which we don't have. Will created the project in his name, and the projects are non-transferable between admin.
And to set one up would cost us money, and the big plus for Fusion 360 is that it's free
@Cruz_Strom & I were discussing the possibility of getting a grinding wheel that works for aluminum, and that drove me to refresh my memory about why a normal grinding wheel doesn't work with aluminum. I found an article that sums it up pretty well: "Compared with other metals, aluminum has