We bought the POL1376 Pololu Simple High-Power Motor Controller 18v15.
We have configured the POL1376 Pololu Simple High-Power Motor Controller
18v15 for a 2 channel (for 2 motor ) RC control. After setting up the RC using the software , we were able to run the left & right motors but one motor always rotate faster than the other motor. All the controllers we setup behave the same way. Urgently need to setup
correctly & deliver to customer before deadline.
Need help asap. Thxs.
Hello.
I just spoke to you on the phone about this problem, but I don’t want to leave this thread hanging in case others have the same issues. The first thing to note is that you should not expect two motors to turn at the exact same speed when supplied the same voltage, even if they are the same model from the same manufacturer. In general, it is very hard to make a robot drive straight without feedback; even a few percent difference in motor speed will lead to a noticeable curve when trying to drive straight. If you do want to compensate for an inherent difference in motor speeds, you can decrease the Max Speed parameter for the controller connected to the faster motor. In RC mode, the maximum input value (as determined during the calibration phase) is mapped to Max Speed, so decreasing Max Speed will basically scale down the motor speed.
That said, it could also be possible that the controllers are not configured properly. The best way to figure out the source of the problem is to see what happens when you change things around. If you swap motors, does the behavior change (i.e. a motor-specific issue) or stay the same (i.e. a controller-specific issue)? If you suspect there is a problem with the controller, I suggest you supply both controllers with the same RC signal and configure them identically (default settings, mixing disabled) and see how the motors respond. If the motor connected controller A behaves consistently differently from the one connected to controller B under these conditions, even when you swap motors around, there is likely something wrong with one of the controllers.
I think the best way to figure out what is going on is to open two instances of the Simple Motor Control Center, with each connected to a different Simple Motor Controller, and to use the status tabs to monitor the inputs and outputs of each controller. This will make it very easy to verify that both controllers are receiving the same inputs and to identify differences in their target speeds.
- Ben
Hello Ben,
Thanks for your patients & help in my matter.
Turns out that one motor did indeed behave differently.
I took your advice & check the controllers setup again. I found that, of the pair of controllers, I only setup the RC for one controllers because I assumed it was applicable for both…big mistake.
Many thxs !
Rdgs,
CK
I’m glad to hear you were able to track down the source of the problem! Thanks for letting us know.
- Ben
