[rnewendyke]

Originally Posted by Bryce2471

Thanks for the quick response. I like your simple code solution, and it looks to not make a large difference in your driving performance.

You will rarely, if ever notice the limited 330 degree motion of the swerves. After we got our drivers used to the fact that they were driving a swerve, we made them aware of the hard/dead stops as we call them (the "nubs" on the bottoms of the gearbox covers and the plates mounted to the outsides of the plates the modules turn on) and created a training program around the fact that the swerves do have that limitation.

Originally Posted by Bryce2471

Do you use drive encoders? Sense your already raping wires anyway, it seems like it might be worth it for you guys.

Originally Posted by pwnageNick

So magnetic tooth counters were mounted to measure the speed of the wheels. There is an encoder mounted above the wheel mounted to the banebot motor assembly (which you can see in the CAD image) which measures the rotation of the modules.

While we have both the tooth counters and the absolute encoders on the modules, we currently only use the absolute encoders in the code.

Originally Posted by Bryce2471

I'm also curious if you give me an estimate amount of time spent on machining and assembling all those custom parts. we spent quite a bit of time on ours, and they only require five parts to be cut on the CNC mill

I can't give you an exact number, but we essentially dedicated a week to machining swerve parts. They were very labor intensive, but the rewards far outweigh the time we gave to create the swerves. Just as Nick said earlier, we would not survive without Genesis Automation, and one of the countless benefits of having them as a sponsor is being able to use their machine shop which consists of two ore more of almost every machine you could ever need including five Bridgeport 2-axis mills, two CNC machines, a manual lathe, and a CNC lathe to name a few.

Originally Posted by CENTURION

Any chance we could get a few more of those sweet, sweet, hi-res photos? The CAD really isn't doing the rest of it justice.

Our next meeting is on Tuesday, so we'll be able to get back to you on that then.

Originally Posted by CENTURION

Do those holes in the hubs create any sort of airflow to the CIM (sort of like a fan?)?

We haven't done much of any kind of testing on those holes acting as a fan so I can't really answer that accurately, but those holes are primarily there to take weight out of the modules.

However, the hubs do absorb some of the heat created by the CIMs, so they are cooled in a way (again, we haven't done much testing on that other than 'hey, these things do warm up'), which we kind of anticipated when the swerves were still in the design phase.

Originally Posted by Bryce2471

These sure look compact. What is the weight per module? How big is the foot print it takes up in the frame?

I always assumed that a swerve like this would take more square inches, but would weigh less.

Right now each module weighs right around 7.5 pounds. If you were to put one of the modules in a box you'd need a 7.5 x 7.5 x 6 or 8 x 8 x 6 inch box (6" is the height). We can and do intrude on that theoretical box in our current chassis, so the foot print is really a dome of sorts from the plate the module revolves around up.

Originally Posted by Joel Glidden

Do you guys press a ring into the Colson to reinforce it, or do the six rods that join the hub halves just go through rubber?

I'm not entirely sure what you're asking so let me know if I need to clarify. There isn't a ring pressed into the Colson, but the hubs do have a little lip on them that extends into the hole machined into the Colson that the CIM goes through. The threaded studs that form a hex pattern around that hole in the CIM are just pressed into a hole drilled into the Colson and they self-align as you start tightening the bolts that hold the hubs onto the Colson.

Originally Posted by Joel Glidden

Do you have a cage for the nylon balls in the thrust bearing part of the module, or do you just let the balls go where they will? Can you tell me how many balls you use in the thrust bearing?

I'm not entirely sure what you're asking, but I'll try to answer as best I can. We do not trap each of the 80 individual balls, but we do have a groove cut into both the top side of the gear and the bottom side of the plate the module revolves around. So the balls are forced to move in a circular path in the grooves we call raises. Let me know if I need to clarify.


Just a little more about the durability of the modules them selves, on our practice bot they have seen well and above their competition lifespan. Somewhere in the ball park of 10 or 20 times that of the competition bot, and for all practical purposes they run the same as the ones on the competition bot. The modules have seen numerous high-speed impacts both in competition and in practice. As mentioned in the Midwest Regional Thread, the modules also withstood an entire day of 3-on-3 in game scenario practice that we participated in thanks to the generous folks at 1625 in which we had the alliance facing the 1625/2338/2451 practice bots dedicated to heavy, in-game style defense.