POST No. 2408138
MX-64 position mode PID controller
2022-07-28 16:42:25 shanghairob
Hi, willison
I am using MX-64 pwm mode, and labveiw code.  

My question,
I read the control algrithm of Mx-64 from emanual, and use wizard2.0 to test it in position mode

  1. I checked, in the position mode,  KP gain is 850, but I dont know what is the delta (target-current) if delta*kp= pwm. the delta is target pos-current pos or target degree- current degree?
  2. I using PWM mode and create my own KP controller I also add my own trajectory planner, I compare my controller and dynamxiel position mode KP controller, dynamixel posiiton mode KP controller is more precisive and stable no vibration. my controller always has 2-3 degree stable error and with vibration.
    in my understand, there are should be the same, so what is the differnece between my own KP controller and dynamxiel KP controller.
2022-07-28 16:42:25
2022-08-16 19:04:42 Will Son


I'm sorry about the delayed response.

When running DYNAMIXEL under the PWM mode, the PID controller won't intervene.

The PID controller works with the Position Control mode or Extended Position Control mode, which only reads feedback from the absolute position.

Therefore, the Current is not involved in this PID controller.

Unfortunately, there is very little information about the internal algorithm that I can share with.

If your PID controller shows a few consistent tick error, you might want to increase the Integral term which will reduce the discrepancy between the goal position and the actual position.

Thank you.

2022-08-16 19:04:42
2022-08-17 10:07:18 rob

thanks, Willson. 

That is what I understand:  for DYNAMIXEL in position mode,  it is not only PID controller which shown in emanual, but also there is some internal algorithm to increase precision.

if this is the reason, which I can understand why my own PID controller which is lower precise than DYNAMXIEL PID controller.

thanks a lot!!

2022-08-17 10:07:18