Running into things with RVR, and "serious motor error"

Should it be OK for RVR to run into things? If it collides with something while running a program, it sounds like the motors are straining hard to try to continue moving. Is this OK? While my kid was playing with a “draw” program, the iPhone app complained of a “serious motor error” after such straining for just second or two. I couldn’t see the details before he dismissed the error message.

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As for the colliding and frantically spinning its treads, that seems to be normal, although I don’t recall ever getting a warning because of it.

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Hey @Steven!

We definitely wouldn’t recommend intentionally running RVR into things, but it is meant to withstand the occasional bump. RVR has the same accelerometer as all of our other bots, but has much more mass, which means, especially at high speeds, it is ramming into things with much more force than our other bots, so it is more likely to become damaged from the “same activity”.

The error you were seeing was likely the “Motor Stall” error. We’ll be posting about all of the light patterns and errors on sdk.sphero.com shortly, but I’ll elaborate on this specific one here, now :slight_smile:

Motor Stall
There are several reasons that the motor on RBR might stall:

  • You continue sending drive commands to RVR while the wheels are stuck
  • RVR has a payload that is too heavy
  • RVR is going up an incline that is too steep
  • RVR is spinning at a speed that causes too much stress on the motors
  • RVR is stuck driving against a surface
  • The treads are being held or restrained in a way that causes stress on the motors

If this happens, the motors will shut down (i.e. RVR will be unresponsive to any drive command) for a few seconds, and then resume normal operation. Additionally, if motor stall notifications have been enabled via the SDK, RVR will send notifications (1) when the motors stall, as well as (2) when RVR can resume normal operation, following a stall.

With all of that said, to prevent the RVR from repeatedly stalling, we recommend that you:

  • Reduce the payload RVR is carrying (if there is one)
  • Ensure you are not driving RVR up exceedingly steep inclines
  • Reduce the amount of spinning RVR does
  • Reduce the amount of time RVR is driving against a wall or surface
  • Don’t hold or restrain the treads while the motors are active

Thanks so much for reaching out and I hope this elaboration helps!!

Kelsey

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