All terrain Closed Robot platform

[Ben]

Hi I am using one of the all terain closed robot platform. I can notice some problem with the motors. It is fine when going straight. But when I try to turn the Robot the shaft of the left side of the front wheel is not turning even though the coil inside the motors turn.

Also If I dont give any directions and try to move the wheels physically, the left motor is difficult to move and also the coil doesn’t turn if I manage to turn the wheels. I want to narrow the problem down to whether it is the motors or the motor controller. The kit uses AX 1500 motor controller and IG42 motors with encoders.

[boombaby31]

It sounds like the set screw in the shaft collar may have come loose from the motor shaft. Loosen the set screw on the shaft collar and slide it toward the wheel, exposing the hole in the shaft. Now line up the hole with the flat spot on the motor and replace the shaft collar so that when you tighten the set screw, it goes through the hole in the shaft and tightens down on the flat spot. Use a medium-strength thread locking solution on this screw as well.

This should solve your problem. Let me know if it doesn’t or if you have any more questions.

[Ben]

Thanks for the reply. But the thing is that the motor work properly when the robot is switched off and I just push the robot manually. The moment I turn it on that’s when it gets stuck. The possible problems I am looking at are the encoders of the motor or the motor controller.

[SuperDroid]

Can you elaborate on the robot working properly when it is switched off?

In your original post it’s sounding like the mechanical assembly that is attached to the motor shaft is loose. If you can observe that the motor coil is spinning but the wheel isn’t, your issue is most likely related to the set screw that secures the wheel’s hub to the motor’s shaft. Which is what Boombaby31 is suggesting could be your fix.

Now, if you want to rule out that there could be something wrong with the motor controller then you can directly apply your robot’s main power to the motor and see how it spins. Alternatively, you could physically swap motor channels to see if the issue follows the motor or the motor channel.

To determine if there could be an issue with your encoders, if you are running in closed loop mode, try switching to open loop and see if your issue goes away.

[Ben]

Hi Jason

It is the problem that boombaby31 pointed out. I tried to align the screw set and tighten it again. It worked fine for few hours then again I encountered the same problem. Is there a permanent fix or has the screw set worn out?
When I meant “Working properly when switched-off”, I mean that both the coil and the wheels are spinning properly when I physically move it by hand.

[SuperDroid]

Have you tried putting some more lock-tite, or similar product on the screw? Be sure that the set screw is going down on the flat side of the motor shaft. It would also help if you use a T-Handle allen wrench so you can get more torque on it when you’re tightening it.

[Author]

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