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Decreasing trolley drift (cart: front steering)

asked 2017-01-22 15:08:58 -0500

vmatos gravatar image

updated 2017-01-25 08:40:01 -0500

I've just modeled a trolley for my robot to pull around, however I can't make it stop drifting. I've added friction to the wheel joints, but it does not produce any effect.

I observe the same drift with the gazebo model 'Cart: front steering'.

The trolley is fully stopped at the beginning of the simulation, but then it starts to move. If I disable the trolley's base link gravity (only wheels remain affected by gravity), it won't move. But removing the effect of gravity on the trolley is not an acceptable solution for me.

Do you have any suggestions on how to make the trolley not drift?

Edit: After removing friction from wheel joints, the robot drifts less.

Edit2: As asked in the answer:

    <mass>5.0</mass>
    <inertia>
      <ixx>0.27</ixx>       <!-- for a box: ixx = 0.083 * mass * (y*y + z*z) -->
      <ixy>0.0</ixy>         <!-- for a box: ixy = 0 -->
      <ixz>0.0</ixz>         <!-- for a box: ixz = 0 -->
      <iyy>0.15</iyy>       <!-- for a box: iyy = 0.083 * mass * (x*x + z*z) -->
      <iyz>0.0</iyz>         <!-- for a box: iyz = 0 -->
      <izz>0.415</izz>       <!-- for a box: izz = 0.083 * mass * (x*x + y*y) -->
    </inertia>
  </inertial>

For the wheels:

  <inertial>
    <mass>0.1</mass>
    <inertia>
      <ixx>0.00001</ixx>
      <ixy>0</ixy>
      <ixz>0</ixz>
      <iyy>0.00001</iyy>
      <iyz>0</iyz>
      <izz>0.00001</izz>
    </inertia>
    <pose>0 0 0 0 0 0</pose>
  </inertial>
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answered 2017-01-24 12:13:03 -0500

JLiviero gravatar image

What do your inertias for the trolley look like?

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Comments

Just edited my question. In the meanwhile I remove joint frictions, and the trolley doesn't drift anymore.

vmatos gravatar imagevmatos ( 2017-01-25 03:21:54 -0500 )edit

After all, it still drifts.

vmatos gravatar imagevmatos ( 2017-01-25 08:40:23 -0500 )edit
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Asked: 2017-01-22 15:08:58 -0500

Seen: 185 times

Last updated: Jan 25 '17