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Pololu Dual VNH5019 Motor Driver behaves erratic

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Eminent Member
Joined: 3 years ago
Posts: 17
Topic starter  

A recurring issue with my RickCar1 robot seems to be my motor driver (Dual VNH5019 from Pololu) giving stopping drive the motors (37D metal gear motors 131:1 from Pololu) connected to M1. It has leds indicating direction the motors should be turning and those work as intended, however, the motor sits idle. At first I thought M1A and M1B (the outputs to the M1 motor) remained 0V and it turns out they don't but the voltage difference is indeed 0V once the motors stopped spinning while they shouldn't.

To confuse me even more, when I turn (by hand) the wheel connected to one of the two motors connected to M1, the wheel connected to the other motor connected to M1 does spin even though the only connections between the motors are the two wires going through the M1A and M1B terminals, even when the battery is disconnected. There is also a measurable voltage difference between M1A and M1B when I turn one of the wheels.

As a temporary fix, I can connect one of the motor connections to the GND of my 12V battery and repeatedly connect/disconnect the other connection of the motor to the 12V of the battery to have it respond again to the motor driver.

Crashes occur during all kinds of driving, including accelerating forward, changing direction, making turns. Any suggestions on how to proceed investigating/fixing this?

Noble Member
Joined: 4 years ago
Posts: 1062

I been using the same motor controller for my main experimental robot (different motors though).  I have not had any issues though I will note that my motors will not spin if too low a PMW value is given and from the range of 1 - 400 I limit this to using 100 - 400.

So many things could be wrong in your setup (from the controller, uno, wiring,  programme) that sadly I don't think I can be of any assistance, though by now you will probably have seen the good advice on troubleshooting in the latest DroneBot video. ? .  Have fun.