Has anyone made a swerve drive that's run on one motor?

[AlexanderTheOK]

Originally Posted by techhelpbb

Agreed it gives you more degrees of freedom of control. Thing is you have to be able to control it.

Controls for a unicorn swerve aren't too complex. If your worry is the programming you can try what we did here and make one out of vex components first. Heck, you could go even further and make it coaxial using these to get it closer to the real thing.

Originally Posted by techhelpbb

I've thought this over quite a bit. As the OP mentions the cost of 4 CIM motors/speed controls to drive steering indepently is pretty high. 8 CIMs risks a good hunk of battery power in addition to driving weight. One could counter that you only use the steering CIMs when you steer but is that not the goal? Assuming one tames the power required or uses a smaller motor with sufficient gearing to steer to overcome this....

No need for cims on the steering. We used 550s on 696 and other than getting hot, there weren't many issues.

Originally Posted by techhelpbb

Is this really a mere 6 week task to gain a degree of freedom that as others have pointed out risks reducing your ability to drive straight?

You actually get the ability to drive ultra-straight, as with four wheels on the ground, it takes more force for them to scrub.

Originally Posted by techhelpbb

Can anyone provide examples of teams that jumped into swerves cold in a 6 week build season and fully exploited it? I am honestly curious my experience is limited to the northeast US. I would be very curious if they bought the modules or borrowed their code to make it work in that timeframe. I can accept it is possible but would like to understand the details.

As sanddrag already mentioned, 696 went in very much cold. While doing it another year and iterating would yield a better design, I don't believe we left out any "features", that is to say, the driver had 3 axes of freedom, the option to drive field or robot centric orientation, and autonomously moving to field centric "coordinates" or "waypoints" (x,y,theta) on the field.

The modules and code were done entirely in house.
I have to say that one of the greatest boons to timely functionality was the construction and programming of the "miniature" swerve. It let us get the math out of the way early so we could focus on individual control of modules.