Skidsteer, brushed with relay changes turning direction at full stick deflection

ArduRover Rover 4.6
1

Hello,

I’m currently in the process of setting up my first rover. The configuration is a skidsteer with 4 brushed motors and 4 Crayton MD13S motor drivers.

The drivers are controled by PWM and with a relay for reverse. The rover works fine and the relay seem to be able to change the motor direction as desired.

My issue is that when I go full throttle forward for example, and than start to turn everything is good at first. But when I get abow a certain stick deflection the wheels change direction resulting in a turn in the wrong direction.

Even more strange. The point of stick deflection (the right stick for turning) where the rover decides to turn in the opposite direction is not the same. It’s proportional to the amount of throttle I use. For example, with very little throttle the rover will change turning direction at very low stick deflection. But at full throttle it will start to turn the wrong way closer to full stick deflection.

I can’t find anything about this. Same issue on both the Cube orange I’m running now and on my Pixhawk 4 mini which I used for a while.

Here’s a link to a video in case my explanation is lacking.

Any advice is greatly appreciated!

2

Tested with the relay input unplugged. The issue disappears. Off course the rover wont be able to run properly since it can’t change the direction of the motors but is should mean that the issue comes from the FC flipping the relay and not the PWM going out of the motor drivers range or something like that.

3

Some random thoughts:

  • Have you calibrated your RC controls?
  • Does the PWM change from the RC move across the full range (I think mine might go from about 900-2000
  • Do the manual buttons on the MC13 correctly move the wheels forward and backward when you press the MA and MB buttons?
  • Look in Mission Planner at the “motor test” feature on Setup and confirm the expected behavior

Start there and also post your config here.
RZ

4

Hi,

I did manage to get it working. I had switched the relays and the reversing behavior wasn’t what I expected as default which made me a bit confused at first. But everything is working fine now,

Thanks!

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