Sudden uncontrolled Movement on Magni


#1

Hi!
We are experiencing that a magni robot may under certain conditions uncontrollably move at maximum velocity.
This is reproducible 100% by the following steps:

  • Start magni motor node
  • Publish a twist message periodically on /cmd_vel (e.g., 0.1m/s forward, 30Hz)
  • Observe Magni moves forward as expected
  • Stop motor node
  • Observe Magni stops as expected
  • Stop publishing messages on /cmd_vel
  • Start magni motor_node
  • Observe Magni is moving at max velocity for a short period of time seemingly proportional to the original velocity.

This looks like the firmware’s integral is winding up when it is in an unconnected state.
Since we regard this kind of uncontrolled movement as a security issue, we would greatly appreciate help with it.


#2

This is a very good problem report with a precise set of steps to reproduce the issue. I will look into this issue at once. Thank you for your clear description.

Because some of your robots have firmware version 32 can you please explain to me if this was seen using version 32 firmware or an earlier revision. This is important.

Can you show me the precise command you use to stop the motor node and the command you use to start the motor node (I believe there are different ways).

In the mean time I will assume you use these:
sudo systemctl stop magni-base.service
sudo systemctl start magni-base.service

Thank you,
Mark


#3

Thanks for the precise set of instructions for how you achieved this - we have been able to reproduce the bug. We are working to get to root cause - but it looks like it is a firmware issue. If that proves to be the point of cause then we will fix it and push out a firmware update.


#4

We’ve opened an issue on this. You can track this issue here as well as add comments or additional information: