I am building a differential drive robot. I bought (2) Jrk24v13 controllers and (2) 37Dx68L gear motors figuring I could have feedback accurately controlling the speed of each motor.
All of the settings for the motors are exactly the same. So I was assuming that when given the same target number input that I would get matching rpm out of the motors. (For when the robot drives straight I need both wheels to rotate at relatively the same speed)
But they are not. One motor is drawing double the current and visibly rotating faster. (No load)
I would think since the encoders are mechanically the same, even if one motor was tighter
that the controller would overcome that with current and make it the correct speed. (But it is not!)
Values I am using on both Jrk:
4 pulse samples
64 Frequency Divider
range from this is 71Hz to 2.86kHz and the motor calculates to be 2640 pulse freq
PID is 20/0/100 for both
PID Period is 30 for both
Using an oscilloscope on both motors FBT pins I matched up the square wave freq by adjusting the calibration fields on the faster motor and now have both motors close to the same speed. But not perfect and still not how I thought closed loop speed should work. What happens when motor wears in more? what happens when I have to replace the motor that breaks with a new one?
Any help would be greatly appreciated!!