Joint Velocity Limits in UR10e

[adawne]

Hi, was there any specific reason why the forcerange for the UR10e and the grouping of the actuators are defined in this way?

I am asking because I noticed that the forcerange of the actuators does not match the values specified in the technical datasheet, even though I understand that MuJoCo is unitless. However, the qvel values (I believe data.qvel is returned in rad/s based on this reference, please correct me if I am mistaken) produced when I attempted to control some joints using data.ctrl sometimes exceed the velocity limit specified in the technical datasheet.

For example, when I tried the following code:

  model = mujoco.MjModel.from_xml_path("mujoco_menagerie/universal_robots_ur10e/scene.xml")
  data = mujoco.MjData(model)
  time_datas = []
  qvel_datas = []



  with mujoco.viewer.launch_passive(model, data) as viewer:
      start_time = time.time()
      num = 0
      while viewer.is_running() and time.time() - start_time < 300:
          # active_motors.print_actuator_parameters(model)
          step_start = time.time()
          current_time = time.time() - start_time
          if data.time > 1:
              data.ctrl[1] = -2.5
          time_datas.append(current_time)
          qvel_datas.append(data.qvel[:6].copy())

          mujoco.mj_step(model, data)
          viewer.sync()

          time_until_next_step = model.opt.timestep - (time.time() - step_start)
          if time_until_next_step > 0:
              time.sleep(time_until_next_step)

I observed that the joint velocities exceeded the maximum limit of 2 rad/s specified in the datasheet
.
Do you have any recommendation on how to maintaining the velocity constraints as per the datasheet?

[kevinzakka]

Hi @adawne, I compared our forcerange values with the "effort" values in the official URDF here and they seem to match. Am I missing something?

[adawne]

Ah yeah, it matches the URDF values. The issue is MuJoCo doesn't have a velocity limit (correct me if i'm wrong), which might be causing the exceedance. Should I add damping or rescale the force range to keep it within spec sheet?