PID actuator

Discussion in 'Modeling' started by jpsb, Apr 6, 2018.

  1. What is the easiest way to model a PID actuator? I am particularly interested on the Integral part.

    Thank you!
     
  2. Emo Todorov

    Emo Todorov Administrator Staff Member

    The integral part introduces another state variable. MuJoCo has 3-rd order actuators designed to model things like pneumatic cylinders and biological muscles. You could adapt it to represent the integral term. Then you need a second actuator for the PD term.

    Alternatively, you could implement this on your end as a feedback controller, and use simple force actuators in MuJoCo.
     
  3. I am not sure whether I should create a new thread (sorry if that is the case) but I have the same question.

    For example I want to simulate this baxter robot which has PID controller for joints, and I need to use same model.
    https://github.com/RethinkRobotics/...m_hardware/config/baxter_sim_controllers.yaml

    I think I understand second part of the answer (using force actuators and implement controller), but first part I am not sure. Is it possible to simulate exact same controller in MuJoCo, if yes what are steps I need to take?

    Thank you.
     
  4. Emo Todorov

    Emo Todorov Administrator Staff Member

    If you are not sufficiently familiar with MuJoCo's actuation model, it may be easier for you to simulate a PID controller in your code, and then provide the resulting forces to MuJoCo as control signals for a torque actuator.