Robot most likely to successfully participate in the YMCA dance
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reminds me of:
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We have one of those (Blue, not orange) as our team mascot. We bought it for a 2018 off-season event and mounted it on the top of the scale as the boss.
Since then he has either been in our pit or in the stands at every event we have attended:
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Sorry if this is off topic, but how do you use this?
What I’m imagining is you put a dowel in a hole, place that on the outside of the tube, mark it and cut it, right?
Seem like it might be good if it had some lips or something to go around an edge so that it stays square a little better, so want to make sure I’m not missing something else
Apologies for the lack of posts. Currently working on an arm write-up and have been a bit busy.
Weekly Recap (ish):
We finally figured out most of the automation for our mechanism, and we’re now scoring! There are still some kinks we need to iron out, but we are starting to transition to drive practice now!
Beta Cad
Beta cad isn’t completely done, but its close enough that I can talk about it.
Main changes:
- Added a cone ramp “Chute Door” for single substation drop
- Increased superstructure width to 10 inches inner for cone passthrough for ramp
- Swapped Deadaxle to MAXspline to compensate to increased forces
- Redesigned superstructure to account for packaging constraints
Playing with a full passthrough system to remove some of the funky indexer logic that we have due to the packaging constraints, as well as make the arm not rely on the intake.
Beta Tradeoffs
- No longer have protection reduction/CG reduction on arm gearbox, it’s closer to the center now but allows for cone ramp
- Cone ramp passthrough means a lot more bending loads on the dead axle, so we switched to a 3/4 dead axle + max spline setup for additional strength (in theory). It becomes a bit more complex, but it allows for a bit more work
- Due to intake and ramp locations, the superstructure design is much more conservative, and the support beams are smaller. Some slight compensation is done through oversized 1/8 gussets. Originally, we wanted to use tie rods, but due to packaging constraints and load directions, traditional box tube supports were easier and faster
Current Issues with beta cad
- Intake and Claw currently hit each other for some odd reason (they don’t hit in alpha, I swear I didn’t change any geometry)
- Claw is still an alpha claw, no redesigns for beta yet, though there is some continuous iteration. (popped a cube by accident through the gears)
- No intake hard stops feel bad. Need to figure out intake hard stops. Not sure why it’s a lot more difficult w/ this intake geometry than alpha, especially because the rollers should be in the same place.
- Electrical Pathing is difficult as ramp and moving arm is in the way. Planning some holes and battery mounting is difficult, especially due to the battery to breaker to pdh wires which are hard to bend. We want to do a solid bellypan too, so that means designing mounting holes for everything, which is a first for me.
- 35 Chain run is long, and there is a chance of breaking the MP bearings… If we do, it’ll be rough because we can’t get MPS anymore due to the shortage.
Current issues with alpha
- “Magic” Polycarbonate is sometimes a bit too floppy and unpredictable, it keeps the cubes in, but does weird things occasionally and you need to find an exact zip-tie location to make it work, which is hard to reproduce in beta.
- Exposed gears on the claw can cause cube ripping, but packaging constraints mean its hard to cover them with standoffs, will try to make a custom 3dp solution potentially (?) (we have like 5 popped cubes)
- Claw inner belt run was preventing the cube from going all the way in. We did a fix IRL by moving the belt run outside but needs to be fixed in CAD.
- We have a lot of electrical issues with sparks randomly not working, and we aren’t sure why. We’ve also been using wagos, and the connections have been loosening on the intake, causing the intake to stop working, as well for some reason really difficult to put the wire back in.
- Claw wheels are wearing out really quickly in testing, running blue stealth wheels and 2 in flex wheels.
Working on an arm design writeup to hopefully help teams design their own arm, will try to post it on Sunday.
Thanks for reading!
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Are you using ferrules on the Wagos? A simple pull test with and without will confirm, that it makes a huge difference on retention.
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have the blue stealth wheels that were wearing out quickly been used in the past? or are they potentially hitting the ground or something else on the robot? I am a tad concerned as we have a similar setup in CAD, but we haven’t fully tested the wheels yet. Maybe they are just something that will need replacing every x hours.
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Oh wasn’t aware that ferrules could be used in Wagos
Can we use them in the rev ones?
Our 2 in squish wheels seem to be wearing a bit too, might be due to the cone? We have a lot of streaks of wheel residue on our cones
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thanks…that cone has been through war
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Are ferrules more secure?
Try current limiting, that’s a good trick.
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Very much so.
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Like spinning
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If you don’t mind me asking, how are you counterbalancing the arm? It looks great
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Right now we’re not, but we are planning on adding a gas spring setup.
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I’ve never heard of that before, and my initial reaction is that it defeats the purpose of wagos, since you have crimp something into the wire.
That being said, I’ll pitch it to my electrical lead, especially if it helps retention.
Do some pull tests with and without ferrules. The wagos bite into the crimps on the ferrules. We are using a good crimper, similar to but not this exact model. Amazon.com
Made an arm design guide based on the learnings from this season. Hopefully, it helps someone out!
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