Motors Spasming

We are running 2 1:1 torque motors on our mini four bar, and it worked fine for a few days, but then now both the motors just spasm when you run. When we took the motors off and ran them, they seemed to run smoothly. We’re pretty sure it isn’t a coding problem because it ran fine initially.
Should we try replacing the motors?

I would still check your code. I suppose it could be a motor controller issue but most times when motors studder it is because they are receiving multiple instructions from the programming at (close to) the same time.

  1. Check your code.
  2. Try plugging the motor controller directly into the cortex then using two wire extensions to the motor.
  1. Any feedback loop in the software? Out 4-bar uses a potentiometer and a PID to control it (even though it only flips between 0 and 90 degrees). We have had issues with noisy potentiometer that caused the 4-bar to jitter.
  2. Check your cables. A typical 4-bar at the end of RD4B means looong cable and several active bends. We have had issue with a claw (even worse thing to wire), where a wire got broken inside the insulation because of frequent bends.
  3. Verify friction. It might have worked fine, then a screw might shifted somewhere or a shaft bend, adding more friction and causing PTC tripping.

Make sure your wires aren’t cut/frayed. I know this might seem stupid, but a bad wire will put more strain on other motors, causing that PTC to eventually trigger (I know cause this happened to us at state).

Check if the motor is loose. Try running the four bar with separate code that uses just direct motor power.