pic: 4587-Sheet Metal Chassis

Ask if you have any questions.

I have made this chassis for practice and to try out sheet metal maybe sometime soon. We have a sponsor with some crazy bending and cnc laser machines so we figured we would try to take advantage of that. What you see here is a Tex-Hex-Coast drive inspired by 148 and 971. It is made entirely of .090" 6061 T6 except for the stainless steel .125" wheel module plates. I also took some design ideas from 3847 and 3928. Leave comments and feel free to leave suggestions. I am trying to make this the best it can be.

Very cool Cooper, a lot of things I plan to look into in the fall are in this.

One thing that I am definitely going to look at adding is a belt or chain connecting the modules on each side. 148 has them this year. I think it’s a huge improvement for when two of the wheel modules come off the ground.

I am also going to try to remove the plates that mount the motors inside of the wheel wells. They caused us problems since they aren’t really piloted with gear they are driving. We have had some gear wear issues because of it.

What gearing is this designed for right now? We are definitely looking at going faster next year with the amount of motors we can put on the drive. We did 6:1 and 14:! this year and we could have probably done closer 5:1 and been fine.

Also I like the third CIM mount, 12 motor drive is the future for sure. (before anyone doesn’t get this, that was a joke)

I have plans to put connecting belts between each omni wheel. There are also places for two tensioners for the belts between the omni wheels that will press down on to the top of the belts.

You are going to remove the interior gearbox plates? Are you going to try to float the motors with the wheels like 1477 did?

It is designed for a 5:1 for 4" Omni Wheels, and 14.4 for the 3.25" traction wheel. Should be good enough for this type of setup. I think the speed will be just right for the type of driving I like to do.

Oh, and those strategically placed Swiss cheese holes may never be used :stuck_out_tongue:

We definitely won’t float the motors. I’m not sure exactly what the plan is yet but the we need a better way to force the plate to be aligned properly if we would do it again. I have also thought about moving the motor mounts to between the two wheels but haven’t actually CADed anything yet.

Originally I had intended to put all four motors in one gearbox in that middle space between the wheels , but I couldn’t really find an easy way to make that work while still making it simple to build. I may do some more playing around with the arrangement. I am definitely going to keep the shape of the chassis like this though. I hadn’t really understood the reason behind 148 and 971’s hex and ocot sided frames until you told me at Comic-palooza.

If this is your first time with sheet metal, definitely talk to your sponsor and find out what bend radius they recommend for a given thickness, as this will be driven by the tooling they use. Usually not a huge deal, but updating this after the fact can be somewhat hairy on complex structures depending on how you define your flanges.

Right now, your radii look far larger than what I typically see used for .090" Aluminum, although 6061 vs. 5052 would call for a larger bend radius. Generally, 5052 is recommended for sheet metal work, but some teams do use bent 6061.

Yes hex chassis designs are going to be very popular in the coming years. Depending the game I wouldn’t be surprised to see 50+ next year. However the GDC could easily through a huge obstacle in the middle of the field and make it harder to use standard drive trains.

The sponsor my team has does use a .25 bend radius for .090" 6061 T6 it does seem big but that’s what they call for for 90* bends. Other angles will be different though with BD and BR I just haven’t put those in.

I feel like GDC has been holding back in terms of field obstacles in recent games. The fields have been mostly ALL flat recently and the real “obstacle” has been defense at least as long as I have seen FRC. It seems like it will be soon that the GDC will put a huge obstacle on the field.

I would agree, especially considering the incessant whining about high-speed defense this year. dividing the field is the best way to prevent this, though 2012 was too defense-less IMHO

Play around with it and see how you like it. Our team was 8 sided this past year and most people assumed it was to prevent getting stuck in pins however the real reason is that the extensions on the left and right sides allowed us to fit our shooter on top of our robot inside the frame perimeter. While we did notice it was slightly harder for someone to pin us we did find ourselves getting stuck because one of the sides would brush up against and object (side wall, other robots, etc) and would spin us into them. Our driver had to learn that he could no longer run up the side of the field and needed to stay several inches away so he could continue to drive in a straight line.

Every team needs to come up with their own opinions but our team won’t be doing a multi-sided robot again for the purpose of making it harder to pin us.

I’ve done some reworking to remove the gearbox motor plates. The motors now mount directly to the channels which contain the wheel modules. I also added a handy battery mount.

Image found here:

What are you using to articulate your modules? I can’t figure out how you plan to drop the traction wheel. :frowning: