2471 Swerve Designs and Programming

[Bryce2471]

This is a picture of a robot Team Mean Machine built for an off season competition this fall. It utilized swerve drives.


This drive base has been discussed previously in a different thread here:
http://www.chiefdelphi.com/forums/sh...d.php?t=121672

I decided to make a new thread, so that it would be easy to find the links to the documents in question.

The programming and CAD designs can be found on git hub:
https://github.com/Tmm2471/Swerve

Here are the files as a zip file on google drive in case you don't like git hub:
http://goo.gl/YG7rQB
The CAD files are all in inventor format.

Since last time I posted to the other thread on this topic, the programming has been improved a bit. It was a robot-oriented control, and the robot was driving quite nicely. The software now adds two check boxes on the smart dashboard for the type of driving control that's requested. One toggles on and off the field-oriented translation. This is somewhat basic to program. Essentially, if the option is selected, then the direction given from the translation joystick (left stick) is added to the gyro heading so that the orientation of the robot on the field does not affect the direction of motion. If you press the joystick in a given direction, it moves that way in field space. The second check box is for field-centric steering. Instead of having the x axis of the right stick correspond to steering power, the right stick direction indicates which direction the robot will face on the field. The direction of the stick specifies the direction for the front of the robot to face.

Here is a short video of the robot running in its bare form, so it's easier to see the wheels.
http://goo.gl/5XdjyV

Here is a video of match play:
http://goo.gl/1l4ZQd

All questions, comments, and concerns, are much appreciated.

[yash101]

That's small! By the way, what game is that for? Is it FTC, or something the team made up themselves?
Over all, how much does the bot weigh? What's it's top speed?

[Blackphantom91]

This is pretty cool! I had the pleasure of watching your team last year at championships and I would think you guys are going to do pretty well. Nice Work!

[Bryce2471]

This is pretty cool! I had the pleasure of watching your team last year at championships and I would think you guys are going to do pretty well. Nice Work!

Thank you, watching you guys play at champs was pretty cool.

By the way, what game is that for?

It played at bunny bots, off-season competition. It's a competition put on by a local team, the flaming chickens (1540). Each year, the alumni and mentors of 1540 come up with the challenge. This year's game was supposed to resemble pool as in billiards.
Here's where you can see the official rules:
https://team1540.squarespace.com/bunnybotsgame/

Over all, how much does the bot weigh? What's it's top speed?

With all you see in the picture, it weighs 88lbs. It goes very fast, we haven't measured it yet, but I would guess about 18-20fps. in the beginning of the competition, it was geared to tall and drained batteries. on the day of, we changed the gearing to much success.

[craigboez]

Originally Posted by Bryce2471

on the day of, we changed the gearing to much success.

When you guys asked to borrow a 2mm broach in the middle of the competition I was quite surprised, and happy I brought mine. Nice job getting your gearing converted and congrats on your Bunny Bot victory.

[magnets]

This is really cool. Thanks for sharing (and uploading to google drive, the github download was estimated at 2 hours.)

[Bryce2471]

When you guys asked to borrow a 2mm broach in the middle of the competition I was quite surprised, and happy I brought mine. Nice job getting your gearing converted and congrats on your Bunny Bot victory.

I was very happily surprised that you guys happened to have one on hand. We owe you one for that. We also owe team 1540 for the use of their lathe.

This is really cool. Thanks for sharing (and uploading to google drive, the github download was estimated at 2 hours.)

Thanks for the interest. I hope that this is helpful to people who are hoping to run a swerve drive. The designs don't include every washer, but they have everything you would need to build one. Also in the file is designs for several past and future swerves. If you're interested, they're in the inventor 2012 folder.

The code on the other hand, is exactly what we ran in competition, including everything. So if anyone is able to wade through it, I think it could be very useful.

[craigboez]

Which Black and Decker gearboxes did you use for your steering motors? Is there a good source for these? I've never seen these used before, but based on the CAD it doesn't look like a lot of modifications needed to be made. Any particular tricks required to get them to work?

[JConnolly]

467 - Inventors of SWERVE drive, and don't worry, we'll be using it this year !

[Bryce2471]

Which Black and Decker gearboxes did you use for your steering motors? Is there a good source for these? I've never seen these used before, but based on the CAD it doesn't look like a lot of modifications needed to be made. Any particular tricks required to get them to work?

I don't know the part No. and such off the top of m head, but I'll get back to you on that after shop tonight. The gearbox is a 27 to 1 ratio. It has the ability to be torque limited, and it's zero maintenance. We have found them very useful in many situations. there are two custom parts, and a couple modifications required, so we made instructions on how to make one. I'll get back to you with that as well.

[Tyler2517]

Your designs are amazing. Out of curiosity what is the fps of your current drive iteration?

[Bryce2471]

Originally Posted by Tyler2517

Your designs are amazing. Out of curiosity what is the fps of your current drive iteration?

It has total gear ratio of 4.375:1
I would guess it goes about 18 fps. We are considering slowing it down some more if we use it this year.

[AdamHeard]

Originally Posted by JConnolly

467 - Inventors of SWERVE drive, and don't worry, we'll be using it this year !

Please, elaborate on this claim.