Trajectory_control problem

1

Hi, I am using odrive 3.6v, I had a few question whcih need you help about trajectory_control setting.

  1. vel_lim setting:
    in doc, we need set vel_lim, acc_lim, so could I understand, the linear section, velocity of motor=vel_lim? is it right understanding?

  2. acc_lim setting:
    there is any rules about setting acc_lim, because I saw some doc of other smart server motor which mentions the acc is below 50% of max_vel.

  3. trajectory algorithm:
    could I understand your algorithm is time_based trajectory planning, which means according to vel_lim and acc_lim to calculate totoal time, and each acc_time, and dcc_time?

  4. cartesian planning:
    my real application is my robot arm to move with a straight line. the pc/arduino will create a set of interpolation of straight line firstly and give target pos to odrive with every cpu loop. So in this application, which mode I should use, trajectory control mode or Filtered Position Control mode.

thanks !!

2

  1. Correct, assuming the displacement is far enough to reach vel_lim.

  2. acc_lim (and decc_lim) depend more on the dynamics you’re looking for, but 50% of max_vel sounds like a reasonable starting place.

  3. Correct. If you’d like you can dig into the source code here.

  4. If you’re streaming setpoints you’ll definitely want to use Filtered Position Control. Trajectory control mode is great if you just want smooth motion. But if you have an external controller defining the trajectory and coordinating multiple axes then Filtered Position Control is the way to go.

1 Like
3

thanks a lot!