2073 is looking into WCD, feedback requested

[billbo911]

Up until now, we have mostly been a KOP drive base shop. KOP on Steroids has been our main chassis for the last few years. We are now looking into switching it up and moving to WCD.
Here is are a couple of renders of our first attempt.





I am not a CAD master by any means, this is done by one or more of our students. I am going to ask them to follow up on any/all questions and suggestions.

We had originally thought we would try to have a single drive belt contained in the frame rails, but found that a single serpentine belt needed to wrap around idler pulleys that were way smaller than the minimum recommended by Gates. So, now we plan on using one internal to, and one just inside the frame rail.

Any comments, critiques, questions, or suggestions will be greatly appreciated.

Full size images can be viewed here and here.

[nuclearnerd]

It's a really nice rendering in any case!

I have no experience with WCD, but your design seems pretty textbook - just missing the shaft collars / circlips needed to hold the wheels on to the hex shafts.

[safiq10]

From what I see it looks good. Like others have said its just missing an clip ring or shaft collars. Everything looks to be functional and it looks beautiful! Best of luck!

[TikiTech]

Howzit!

We started using WCD last year and really like the performance. So unless the game dictates otherwise we will be using it again, though possibly a hex frame 8 wheel WCD.. I posted earlier
..
A few things.. Top render has the transmission constrained on the wrong side of the drive rail.

You will be better off not using the versa blocks on the center and just drilling your center hole to use the WCD gearing block.
http://www.wcproducts.net/217-3634/

You will also need to drill a few holes on the drive rail for the bolt heads on the transmission plate to nest into. This will allow the transmission plate to rest against the drive rail giving much better support. You can run a dual sprocket on the transmission to drive each of the outer wheels.

I suggest #35 chain. We have been using #25 but last year we had to tension the chain more often due to our use of the WCD 3 CIM dual speed transmission. (great transmission by the way)

Also factor in a chain/belt cover. Nothing is worse than an electrical wire getting in there. Most of the time an encoder is mounted to one of the outer wheel shafts. Plus the judges like things to be safe!

I am sure I will think of more after I post this..

Good luck with this, looking good!
Aloha

[Michael Corsetto]

Bill,

We should arrange an in-person design review in December. It would be a great experience for both teams. We're not too far away after all

-Mike

[billbo911]

Originally Posted by Michael Corsetto

Bill,

We should arrange an in-person design review in December. It would be a great experience for both teams. We're not too far away after all

-Mike

Excellent idea! I know we plan on meeting with your team leadership to discuss CCC, maybe we can coordinate both things happening at once?

Everyone else, THANKS!! Please continue the feedback!

Great observations and suggestions so far. Correcting these details will go a LONG way to make this a successful endeavor!

[JesseK]

It looks like this setup only mounts the WCP gearboxes via 2 #10 bolts. Could you or your students provide an exploded view, or a close-up view, of the gearbox, rail, intended bearings, and all bolts around one side of the bot's center wheel? Making the rail transparent or semi-transparent would also help.

[billbo911]

I'm working with the student who created this to get his CD account set up so he can respond directly to these questions. The team is out of school this week, so communications are a bit slow. I hope to have him up on the board later today.

Originally Posted by JesseK

It looks like this setup only mounts the WCP gearboxes via 2 #10 bolts. Could you or your students provide an exploded view, or a close-up view, of the gearbox, rail, intended bearings, and all bolts around one side of the bot's center wheel? Making the rail transparent or semi-transparent would also help.

Thanks for the request JesseK, we will work on getting that up ASAP.

[AustinSchuh]

Looks like you have ~1" between the bumpers and the wheels. Consider pushing your wheels out a bit further. That'll give you more room inside the base for your electronics.

Why not stand the battery upright? The bumpers will extend to the top of the battery anyways, and you gain a bunch of space back.

The 20/30 amp fuses are hard to get to and see. Move the radio up a lot, or somewhere else.

Considering that the electronics will change next year, can you get models of them and try fitting them into your base instead? That'll be more valuable (and they are smaller!)

[R.C.]

Bill,

The things I would change:

-Don't use a full versasblock per gearbox, use 1/2. And mount the gearbox so the face of the gearbox is flush.

-Use the WCD 2 CIM DS and ditch the belts inside the tube. Go to 18T sprockets and run chain, you'll be much happier. If you still want to run belts, I would read some of the posts/docs on here about tooth size and width of belts.

I would comment on the electronics layout but Austin has me beat!

[chrisfl]

Do you have the center wheel dropped lower? If so, how much lower? I think I have seen some teams that did not drop their center wheel, how much of a difference is this? Is it beneficial or not? For those that did not drop the center wheel, would you recommend it?

[RandeJ]

We're also looking at WCD this year and doing something similar to your setup. We are mounting the gearbox with the WCD mounting block and then using chains & sprockets to get to the other wheels. Pic show concept - brown items are the chains (not belts).

Definitely planning some sort of chain guard/cover.

[Saool]

Originally Posted by AustinSchuh

Looks like you have ~1" between the bumpers and the wheels. Consider pushing your wheels out a bit further. That'll give you more room inside the base for your electronics.

Why not stand the battery upright? The bumpers will extend to the top of the battery anyways, and you gain a bunch of space back.

The 20/30 amp fuses are hard to get to and see. Move the radio up a lot, or somewhere else.

Considering that the electronics will change next year, can you get models of them and try fitting them into your base instead? That'll be more valuable (and they are smaller!)

Thank you for the feedback. I will work on moving the wheels out more, it will definitely help with getting more space inside the frame. Standing the battery upright was done at first and i simply forgot about it, that will for sure be done. As far as cadding in the new electronics goes i have done that and its simply a seperate render. After putting those in there is alot more space also considering the new speed controllers are stackable. Anything more advise will be highly appreciated. Also the reason for using old electronics is this will possibly be used as a practice run for our first WCD, i dont beleive we will be buying the new control system for it.

[philso]

Originally Posted by mlantry

I'm unsure if the little tabs on the edges are for bumpers but if they are I would either come up with a way to support them or a beefier way because I could see though bending easily if a team gets under you bumpers. Aside from that looks good

It looks like you are using 2 x 1 inch tubing for the frame and the "stubs" between the wheels for supporting the bumpers. If you are anticipating playing a hard hitting game like this years, the bumpers may "pivot" inward on the top edge of the stubs and the front and rear cross members when hit hard. You may want to consider stacking another piece of 2 x 1 on top of the stubs and the front and rear cross members. Some spacers may be needed where you have the gusset plates. Alternatively, use 3 x 1, or larger tubing.

Originally Posted by FrankJ

Keeping in mind that it has the 2014 controls.... Anything under the CIMs is going to be hard to access. You would also want to make your radio platform easy to remove so you can get to PD board. Depending what ends up on top, you might want to face your pneumatic controls & gauges out. The disconnect switch looks a little buried. You obliviously have a little rearranging to do to make the belts work.

It would be best to locate the battery and input breaker at the end with the PDB and the motor controllers and rotate the PDB by 180 degrees to minimize the lengths of the high current paths. Ensure that you do not cut off access to the battery with your upper structure. Use the space between the CIMs to run wires between the two halves of the chassis. Allow at least an inch of space along each side of the PDB and the Digital Sidecar to allow for the wiring in and out. I would suggest allowing the same clearance around the new RoboRio.

You may want to locate the CRio and Digital Sidecar together on one side, say where you currently have pneumatic valves and compressor. Locate the compressor where the air tanks are now. The air tanks are pretty light so they can be put in the middle or up on the upper structure. You may want to install the pneumatic gauge higher up and turned around (as Frank suggested) so it can be seen over the bumpers.

Moving the radio to the other end will put it closer to the CRio that it connects to and away from potential noise sources (motor controllers). If possible, mount the radio on a light piece of plastic in a space in the upper structure so that it is physically protected and not surround it with metal (for better reception).

[Saool]

Originally Posted by JesseK

It looks like this setup only mounts the WCP gearboxes via 2 #10 bolts. Could you or your students provide an exploded view, or a close-up view, of the gearbox, rail, intended bearings, and all bolts around one side of the bot's center wheel? Making the rail transparent or semi-transparent would also help.

Thank you for your feedback. Yes the gearboxes are mounted on by only 2 bolts, i was wonderig of a way to fix that and R.C. has responded with a great idea. I will be editting the cad to allow better contact. If you would still lile to see the exploded view let me know and i will happily render it out with the frame's transparency changed, it just that knowing we will probably be changing to chain it we wont have that issue any longer