pic: 2108 Swerve Drive

We’re going with a swerve drive system this year! We’re using our Shuffle to drive the wheel itself, and the window motors to turn the entire system.

The wheel system is based off of the Revolution Swerve sold by Team 221. We have opted to make our own because its (a) cheaper, and (b) going to be ready before any more Revolutions are commercially available.

Feel free to provide comments/concerns/criticism.

about how much is that gonna weigh? other that that very nice.

Looks nice!

Just one little question. What reduction (if any) do you have going from the window motor to the wheel? [Looked at the picture again and it looks like its about 1:1] If its too much of a reduction, your wheel’s turning will be so unresponsive that it will be difficult to truly utilize your swerve. On the flipside, if your reduction is too little, that poor little motor won’t be enough to do the job.

The reason I mention this is because we used a window to steer last year. The wheels were extremely responsive (1:1 ratio off motor), but the motor did feel the beating, getting hot and eventually tripping the internal heat breaker (who knew it had one of these?). Granted, it was 1 window to steer 2 wheels at once, and it took at least 30 minutes of practice before we encountered this problem, but remember that it was also slick wheel on slick surface. I see that you plan on using a high traction wheel (on carpet).

The design looks extremely robust, although its a little difficult to tell how thick all those plates are. Maybe there’s a little excess material? Of course, if weight isn’t an issue, then who cares?

Overall very nice design. Out of curiosity, you don’t plan on climbing the ramp, do you?

Where is the position sensor mounted and what are you using for it?

This is awesome! We considered a swerve for a little while before deciding on mechs since we used them fairly well in 2007 :rolleyes:
We’ll see you guys at VCU, right? Maybe we’ll find ourselves on the same alliance again.

Good Morning,

Since Rob is in class I will take a moment to answer a few of the questions.

Answer is there is no reduction. The teams experience from using this motor last year, is that it is a respectably durable piece of equipment. We used it to run our spindle last year, so we know it can take a beating.

I will leave that up for Rob to tell. It’s his design, and knows what the limitations are better than I do. I need to sit down with it some more this afternoon and go over it.

We haven’t quite figured out where we are going to add it. Also the students are trying to figure some programming thing out for it that they want to do special.

Of course! Wouldn’t miss it. We will be at VCU, the new North Carolina Regional, and Atlanta this year!


this looks fairly close to what we at 1927 used last year only compacted together

How is the wheel module held on? Without seeing the bearing/plate mount, I can’t tell if this advice will be useful or not, but here it goes. Have you thought about having supports on the front and back between the two side plates? They aren’t strictly necessary, depending on how you’ve set everything up, and with that thickness aluminum, it should be fine either way, but on the other hand, it’s a nasty bump…

Otherwise, nice compact design, I like the setup!

Unless you want to have 1 motor drive more than 1 wheel, integrating the drive motor and transmission into the crab pod might save space and possible a little weight too (less of that giant plate). We had 2:1 window motors last year for the rear pods on our robot (two motors for two wheels, the front two had Globe motors), and they worked very well. We also had ~3:1 reduction from window motors on a crab-drive system in 2005. It worked, although we didn’t end up using it because moving sideways with a tetra led to instability. Also, you should be able to turn down the window motor coupler and fit a sprocket on it, then drill new holes and bolt it to the coupler, no need for that shaft on top. Then you can mount the potentiometer to the shaft mount on the coupler, with a keyed ring (to change size) and a set screw.

AHH MAN! I didn’t even think about crab with the 4 window motors and 5 CIM’s this year. it’s like the jeep hurricane concept. im just mad that it didn’t even occur to me before. I hope i get to Be your robot Inspector.


EDIT: (Explicit link content warning) ALSO! its easy to remember your team number because J-ROC from Trailer Park Boys made an “album” named 2108 in the Special Say goodnight to the bad guys that wrapped up the series and transitioned into the latest movie Countdown to liquor day.

It looks great rob, I hope it works well.

I may be a little late with this response but how do you keep the part that rotates on the vertical axis (the wheel), firmly attached while allowing it to rotate freely? I’m trying to design a crab drive module of my own and this is the part that I’m stuck on. I know there is a way to do it but I don’t really know how. Every way I come up with seems inefficient. Thanks in advance.