Thanks pf26, appreciate the reply. You're quite active here and super knowledgeable. Do you have any links to recent work you've done? A while ago I saw you using a VESC to control the pitch of an airfoil, but that was ages ago. I'm curious what you've done since.
I'm definitely going to look at the wireless control - I was trading CAN vs. UART vs. PPM and all the while forgot wireless control was available. For the 3 motors NOT going through sliprings (these control the yaw or pointing angle of the wheels), I'll stick with CAN, but run a shielded cable (CANH, CANL, GND) from the microcontroller transceiver to the three nodes serially, and terminate with a 120 ohm resistor (the microcontroller transceiver already has terminating resistors for both of its channels).
Re. DOFs, there are three wheels, but 6 DOFs and 6 motors. Each wheel has a drive motor to spin the wheel, but then also a yaw motor to aim it. It's called "swerve drive", and it's pretty popular in first robotics among other applications. Never to this power level/package size that I've seen though. I advised and had a senior design team build it for me this past year: https://swerveroboticsystems.github.io/
Bad news - two days ago it looks like I may have simultaneously bricked all 6 of the VESCs on the robot in parallel. Just when I was getting confident to give them all power simultaneously. All I did was switch all the CAN rates from 500K to 125K, thinking that might help with the comms issues. I likewise switched the microcontroller transceiver code to 125K, and may have made some other small changes (position mode instead of RPM), but when I hooked it up, the motors buzzed like they were in position control mode, then the sound slowly faded, and I got the dreaded red blinking LED. 2x blinks, even after restart. VESC tool doesn't show any faults in the terminal though. I can connect and measure resistance/inductance, but when I try and measure the flux linkage, the motor doesn't rotate or try. Are my DRV8302's toast? And before I think about buying 6 new VESCs, is it feasible to replace these, assuming I had access to proper equipment - which I probably do.