Joint friction and damping

<joint name="joint1" type="revolute">
  <axis>
    <xyz>0 0 1</xyz>

    <dynamics>
      <friction>0.2</friction>
      <damping>0.1</damping>
    </dynamics>
  </axis>
</joint>

friction

Joint friction is the resistance inside the joint motion itself

• constant resistance
• independent of speed

Too much friction

• joint won’t move
• controller seems broken

Too little friction

• joint oscillates
• unstable control

Damping

behaves like viscous friction

• increases with velocity
• smooth effect

Demo:

xacro joint_friction.sdf.xacro > /tmp/my_world.sdf && gz sim /tmp/my_world.sdf

• code
• helper macro

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Reference

• original code