Robot runs motors at last values when reconnting

Our robot has “taken off” unexpectedly a few times. I think it may have to do with the lost of communications between the driver’s station and the CRIO. So though I would FORCE some communication losses and see what happens.

For the moment, ignore why a loss might occur. We will move the wireless bridge on the robot to a better place for the competition.

It seems the controller on the robot remembers the last values of its motor drives when it looses communcations. If you turn on a motor and unplug the network cable from the drivers station to the router, the robot stops and goes into no communications mode (fast blinking robo signal light). When it establishes communication again, it runs the motor a short time and then cuts it off (if it the joystick is centered).

If you start a motor and then turn off the driver station and or router while the motor is running, it immediately turns off the motor which is good. When the driver’s station and router are turned back on, it takes around 30 seconds to reestablish communications. When it does, whatever motors were running when communications were lost come back on. The motor(s) then run for 10-15 seconds before an update from the driver’s station arrives and turns the motor off. The controls don’t work at that point, only the disabled switch will stop it.

Finally a question: Is there a way to detect the no communications mode and turn off the motors. We are currently using the Simple template but have played with the Iterative robot base class. The robot is not disabled so I’m not sure the DisabledInit() method would be called.

My theory is that a short loss of communication will cause the robot to run out of control for 10-15 seconds.


LabVIEW code hasn’t returned the same results you described here, at all if ours loses connection it just zeroes everything. Maybe, set all PWM Outs to zero in the C++ equivalent of TeleOp-Reset mode?

Just something to try