16 Falcon 500 8WD Compliant Wheel Drive Train

Hello Summer ChiefDelphi! Off to a great start, I see. Inspired by @Connor_McBride’s compliant wheel swerve the other day, I thought I would one up him with the drive train to destroy all other drive trains.


A genuinely unstoppable drivetrain in two directions


I think you need more downforce, maybe 95s vacuum could help increase traction?


Those falcons seems awfully close to the edge of the robot. For that reason, I would say this chassis probably wouldn’t be all that good. IMO.


THAT’S your only issue with this?


bruh how many passes did you do in that render??

Like, 5?


What gear ratio did you design in?

We designed in ~8:1 gear ratio with NEOs.
If I drop in a Falcon instead, and bump the quantity to 16, I find that a current limit of 15 Amps per motor will keep the system in a traction condition.
Same exercise with 8 motors and a current limit of 30 Amps.
Performance difference?

Very little:
Motor Qty Weight G/R Amps Max speed Time to 10 ft/sec Speed at 2.5 ft/sec Time to 25 ft
Falcon 8 145 7.56 30 20.82 ft/sec 0.518 sec 9.86 ft/sec 1.81 sec
Falcon 16 145 7.56 15 20.18 ft/sec 0.564 sec 9.39 ft/sec 1.868 sec

Oh something would be destroyed alright. I wonder how many seconds those green compliant wheels would last lol


Remove the constraint of the FRC rule book.

Run 4 PDPs
Use 4 batteries
Change the wheels to Rhino track
Add cleats
Chrome moly frame.

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While you’re at it, swap out your 40A breakers with some nice 100A ones.

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Reminds me of the swervinator, which has 12 PDPs and batteries.


The builder of overhaul from battlebots is actually building a 30 pound robot with compliant wheel drive:
uberclocker partly finished


Needs more Slim CIMs


From the reddit comments:

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When I worked at AndyMark, the mechanical engineering department had a special run of HiGrips made with the 35A green tread for testing. On a full-weight AM14U3, they lasted about 90 seconds.

With the bigger voids, I give the compliant wheels 30 under the same conditions.


Ok but for those 90 seconds, I bet you were immovable ay?


Dang why these weren’t released???

On a more serious note - these could’ve been used for intaking stuff nicely IMO if there were 4" variants of these (I don’t know whether they come in 4"). Since it’s thicker than stealth wheels they could probably replace these in various applications

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The test run was in 4". I took two from the junk pile for a Fight Night robot and still have them. (I can see them on the shelf from where I sit.)

I don’t think you really want them in HiGrip form. Because HiGrip wheels have a hub-or-bearing bore, you have to run one of them to make the wheel spin. That makes for wheels that are awful heavy and expensive by modern standards. Both are 1" wide at the tread (the hub of a HiGrip makes it thicker), so that thickness is a wash.

If you meant that there’s a greater tread depth overall on the HiGrip (which there is to an extent), then you’d have to justify two things:

  • Are you really going to need to tap into that additional depth between now and your next long opportunity to work on the robot (probably lunch or the end of the day)?
  • Is absolute softness of tread durometer so important that you can’t put a little harder (and longer lasting) compound in that spot? We had some green compliant wheels on last year’s intake, but once it got to the off-season we put blues on so they’d last longer at demos without maintenance.

@andymark Please release these wheels immediately. Sure we may have to replace wheels every match, but the UNSTOPPABLE POWER will be well worth it. Needing to make a choice of which wheels to run based on team strategy and the expected defense/offense strategy of the opposing alliance, will be a very interesting thought process to go through.

Time to start training drivers with tyre wear reduction driving techniques, and training the pit crew how to change tyers in 2 seconds.


Do FRC fields have a racing line?

If you “put your foot down” and get the wheels to spin and the rubber melts, you can get an even higher CoF and even more traction.