joint oscillations when using jointControllerState.h

asked 2014-10-01 10:45:43 -0500

Marcus gravatar image

Hey guys,

I am using the following simulated actuator on my robot model:

<joint name="camera_joint" type="revolute">
    <axis xyz="0 0 1" />
  <limit lower="-${M_PI/2}" upper="${M_PI/2}"  effort="50" velocity="1"/>
    <origin xyz="0.0 0 0.08" rpy="0 0 0"/>
    <parent link="pan_link"/>
    <child link="camera_link"/>
  </joint>

and

<transmission name="pan_trans">
  <type>transmission_interface/SimpleTransmission</type>
  <joint name="camera_joint"/>
  <actuator name="camera_pan_unit">
    <hardwareInterface>EffortJointInterface</hardwareInterface>
    <mechanicalReduction>1</mechanicalReduction>
  </actuator>

Now I can access the joint and set new orientations for it. However, when I send joint positions in my control loop the joint seems to always oscillate a bit, which is quite irritating especially since I have a camera mounted on this joint which needs to track some features.

I have attached an example of the tracking in which I keep the position I send to the joint the same ( basically not changing the angle anymore) and you can see that the camera is still moving slightly).

I would be very interested in any suggestions Marcus

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