Andymark rhino drivetrain discussion

[RacerX]

The turnbuckles are in compression to keep the belt tight, not in tension. It would take quite a bit to get to the point where the eye bolts are opening. If things get that out of hand, the eye bolts opening will likely be the least of our worries....

As a suggestion, it would be a good idea to have jam nuts on one end of the turnbuckles to make sure they stay where you want them.

[JamesCH95]

Originally Posted by RacerX

The turnbuckles are in compression to keep the belt tight, not in tension. It would take quite a bit to get to the point where the eye bolts are opening. If things get that out of hand, the eye bolts opening will likely be the least of our worries....

As a suggestion, it would be a good idea to have jam nuts on one end of the turnbuckles to make sure they stay where you want them.

I know that the turnbuckles are in compression, which is what concerns me. It may be fine as-is, but the 2 grams of mass it would take to weld it closed seem more than worth it to me.

[Jon K.]

Originally Posted by JamesCH95

I know that the turnbuckles are in compression, which is what concerns me. It may be fine as-is, but the 2 grams of mass it would take to weld it closed seem more than worth it to me.

I would be more worried about weakening the aluminum at the weld. We at AndyMark did extensive hit tests on these turnbuckles at full speed with a fully weighted chassis into a piece of diamond plate that was backed by a full pallet of roller chain, so it had no where to go. We are working on putting up some videos of our testing so that the community can see what we have done to test the modules before we were comfortable selling them.

[Michael Corsetto]

Originally Posted by Jon K.

I would be more worried about weakening the aluminum at the weld. We at AndyMark did extensive hit tests on these turnbuckles at full speed with a fully weighted chassis into a piece of diamond plate that was backed by a full pallet of roller chain, so it had no where to go. We are working on putting up some videos of our testing so that the community can see what we have done to test the modules before we were comfortable selling them.

Jon,

As part of your video tests, can you run a test of the Rhino track system being pushed sideways by another robot (both at 140lbs)? Specifically:

Robot A - Rhino Tracks (~140lbs)
Robot B - Kitbot (~140lbs)

Robot B pushes square onto the side of Robot A.
Robot A does not move.
As Robot B pushes Robot A, Robot A attempts to drive forward/backward.

If you could test the above scenario, that would be awesome!

Thanks,

-Mike

[RacerX]

If it becomes an issue with the tread being pushed off the wheels with side load, which I doubt will happen with a properly tensioned belt, can the Rhino Teams add a plate to the sides of the wheels, slightly larger than the wheel, so it overlaps the white part of the belt?

This would be similar to the other belt pulleys that are used.

In addition to the plates, perhaps a mechanism to deflate pneumatic tires could also be added?

[EricDrost]

Originally Posted by RacerX

In addition to the plates, perhaps a mechanism to deflate pneumatic tires could also be added?

Not comparable. Treads coming off a tread drive (ANY tread drive) from base to base interaction is a chassis that cannot withstand the rigors of FRC. Poking holes in pneumatic wheels is damaging and deliberate contact inside the frame perimeter.

Causing a team with under inflated tires to pinchflat under heavy defense is the parallel.


I'd be very interested in seeing the results of the test Mike has outlined.

[JamesCH95]

Originally Posted by Jon K.

I would be more worried about weakening the aluminum at the weld. We at AndyMark did extensive hit tests on these turnbuckles at full speed with a fully weighted chassis into a piece of diamond plate that was backed by a full pallet of roller chain, so it had no where to go. We are working on putting up some videos of our testing so that the community can see what we have done to test the modules before we were comfortable selling them.

The eyelets in the turnbuckles are aluminum? What alloy?

They appear as zinc-plated steel eyelets with an aluminum body, but you would of course know better!

Posting test videos would be a great way to address concerns of their robustness given the long the somewhat sordid history of treads in FRC drives. I look forward to seeing them!

[JamesCH95]

Any updates on videos or turnbuckle materials? I am still quite curious.

[team222badbrad]

Originally Posted by JamesCH95

Any updates on videos or turnbuckle materials? I am still quite curious.

https://www.youtube.com/watch?v=v8oMG5NQS0o

[Jon K.]

Originally Posted by JamesCH95

Any updates on videos or turnbuckle materials? I am still quite curious.

James,

Sorry I missed your previous question. I am not sure what I was thinking when I was talking about weakening the aluminum at the weld. The outer body is aluminum, but the threaded rod and by extension the eyelets are steel. We did do some more testing with the chassis regarding t-bone tests, and have that up on the AndyMark YouTube channel, as posted above. I know we had some problems getting the videos to merge properly to post the testing to the channel, but I will see what we can do about getting the tests duplicated or uploaded individually. I know given the discussions happening here that we may have more testing videos once the pulleys have been updated.

[JamesCH95]

Originally Posted by Jon K.

James,

Sorry I missed your previous question. I am not sure what I was thinking when I was talking about weakening the aluminum at the weld. The outer body is aluminum, but the threaded rod and by extension the eyelets are steel. We did do some more testing with the chassis regarding t-bone tests, and have that up on the AndyMark YouTube channel, as posted above. I know we had some problems getting the videos to merge properly to post the testing to the channel, but I will see what we can do about getting the tests duplicated or uploaded individually. I know given the discussions happening here that we may have more testing videos once the pulleys have been updated.

Cool, thanks!