Victor Controller Troubles

Technical Technical Discussion
1

Hi all,

We’re having a slight oddity on our robot’s drivetrain. Everything seems fine, but when we start to move the drivetrain it kind of stutters. It’s not too evident, our drivers can correct for it, but it’s really kind of annoying just to have a problem that exists. The stuttering is quite quick and probably lasts ~100-200 ms. Looking at some probes in LabVIEW, I can see that the joystick values are fine and stable, but doing some digging in the Arcade Drive VI, digging into where it actually sets the motor speed, I can see that it’ll set the motor to the correct speed, go to zero for a very short period of time, and then go back to the correct speed. This happens very fast for all the drivetrain motors.

And I’m not sure if this is related but all our victors seem to be going slightly crazy for color indicators. They’re not solid red/green/yellow anymore and more like in a disco dance mode - flashing between all of the colors very quickly it appears. I’m not sure if it is all the colors, but it’s certainly like a strobe light and appears abnormal. Though they still work fine spite the small bug described above.

Anyone know what could be causing this? I’ve never known to Victors to have trouble - usually they just work.

-Tanner

2

The Victor will act weirdly if you select Jaguar in the code, because it will change the update rate beyond what the Victor can handle.

3

That’s not it. Our drivetrain is selected to use Victors.

Thanks
-Tanner

4

This almost sounds like the robot is being disabled for a fraction of a second. The Victors will go blinky yellow when this happens. Does the Dashboard give an indication that the Watchdog is shutting down the robot briefly?

5

I do not believe so.

-Tanner

6

I think the problem was that I had some code in LabVIEW that I was not using, but it was still there (yeah, bad idea) so it was available to run. I think it was just setting the motors to zero every so often, spite what the joysticks said as it ran in parallel to it.

At least that is what I think it is. Haven’t tested it yet (lack 'o robot), but it seems like a good theory.

-Tanner