Joint Velocity Oscillations for Wheel

Help
,
1

Hello,

I’m experiencing issues with joint velocity oscillations in Gazebo while simulating a robot using ROS 2 and ros2_control. I’ve configured a tricycle drive robot with the following components:

  1. Base Link: A large base with a mass of 60 kg (scaled down from the real robot’s mass of 2500 kg) and a center of mass offset.
  2. Steering Link: A link for front-wheel steering, connected via a continuous joint.
  3. Traction Wheel: A drive wheel with a mass of 15 kg.
  4. Rear Wheels: Two supporting rear wheels with a mass of 2 kg each.

The problem is that the reported wheel velocities (via /joint_states) oscillate significantly.
: Increasing solver iterations (iters=400) noticeably improved the behavior but didn’t fully resolve the velocity oscillations.
I scaled down the mass and inertia of every part of the robot (from a real-world mass of 2500 kg to a simulated mass of ~60 kg for the base link).

Played with friction coefficients (mu1, mu2) and damping (kp, kd) across all wheels.

I’m using gazebo version 11 on ros2 humble

image
image1156×1021 21 KB

gazebo>

$(find robot_description)/config/my_robot_controllers.yaml

<ros2_control name=“GazeboSystem” type=“system”>

gazebo_ros2_control/GazeboSystem


<command_interface name=“position” />
<state_interface name=“position” />
<state_interface name=“velocity” />
<state_interface name=“effort”/>

</joint>
<joint name="traction_joint">
  <command_interface name="velocity" />
  <state_interface name="position" />
  <state_interface name="velocity" />
  <state_interface name="effort"/>
</joint>

<link name="base_footprint"/>

<joint name="base_joint" type="fixed">
  <parent link="base_footprint"/>
  <child link="base_link"/>
  <origin xyz="0.0 0.0 0.04" rpy="0 0 0"/>
</joint>

<link name="base_link">
  <inertial><!-- The mass and inertia are divided by 60, the Gazebo engine (ODE) seem to have trouble with large mass-->
    <origin xyz="1.131 0.0 0.89" rpy="0 0 0" />
    <mass value="60" />
    <inertia ixx="43.17" ixy="-0.11" ixz="-5.81"
            iyy="48.53" iyz="0.09" izz="18.5" />
  </inertial>
  <visual>
    <origin xyz="0 0 0" rpy="0 0 0" />
    <geometry>
      <mesh filename="file://$(find robot_description)/meshes/base_link.stl" />
    </geometry>
  </visual>
  <collision>
    <origin xyz="0 0 0" rpy="0 0 0" />
    <geometry>
      <mesh filename="file://$(find robot_description)/meshes/base_link.stl" />
    </geometry>
  </collision>
</link>

<gazebo reference="base_link">
  <material>Gazebo/Gray</material>
</gazebo>



<link name="traction_wheel_link">
  <visual>
    <geometry>
      <cylinder length="0.08" radius="0.155" />
    </geometry>

  </visual>
  <inertial>
    <origin xyz="0 0 0" rpy="0 0 0" />
    <mass value="15" />
    <inertia ixx="1" ixy="0" ixz="0" iyy="1" iyz="0" izz="1" />
  </inertial>
  <collision > 
    <geometry>
      <cylinder length="0.08" radius="0.155" />
    </geometry>
  </collision>
</link>

<joint name="traction_joint" type="continuous">
  <parent link="${parent}" />
  <child link="traction_wheel_link" />
  <origin xyz="0 0 0.0" rpy="-1.57 0 0" />
  <axis xyz="0 0 1" />
  <dynamics damping="0.5" friction="0.7" /> 
</joint>

<gazebo reference="traction_wheel_link">
  <material>Gazebo/Black</material>
  <mu1>0.7</mu1>
  <mu2>0.7</mu2>
</gazebo>




<!-- <link name="${prefix}_wheel_link">
  <inertial>
    <origin xyz="-1.94289029309402E-16 -0.0571500000000001 0" rpy="0 0 0" />
    <mass value="1.47749436881024" />
    <inertia ixx="0.00226827782805257" ixy="-3.16660954114216E-18" ixz="0"
             iyy="0.00136627908669598" iyz="-4.10206903007842E-35" izz="0.00226827782805257" />
  </inertial>
  <visual>
    <origin xyz="0 0 0" rpy="0 0 0" />
    <geometry>
      <mesh filename="$(find robot_description)/meshes/small_wheel_link.STL" />
    </geometry>
  </visual>
  <collision>
    <origin xyz="0 0 0" rpy="0 0 0" />
    <geometry>
      <mesh filename="$(find robot_description)/meshes/small_wheel_link.STL" />
    </geometry>
  </collision>
</link>

<joint name="${prefix}_wheel_joint" type="continuous">
  <origin xyz="${x} ${y} ${z}" rpy="0 0 0" />
  <parent link="${parent}" />
  <child link="${prefix}_wheel_link" />
  <axis xyz="0 -1 0" />
  <dynamics damping="0.1" friction="0.1" />
</joint>

<gazebo reference="${prefix}_wheel_link">
    <material>Gazebo/Black</material>
  </gazebo> -->

  <!-- right wheel Link -->
<link name="${prefix}_wheel_link">
  <collision>
  <geometry>
    <cylinder length="0.08" radius="0.06" />
  </geometry>
  </collision>
  <visual>
  <geometry>
    <cylinder length="0.08" radius="0.06" />
  </geometry>
  <material name="Black" />
  </visual>

  <inertial>
    <mass value="2" />
    <inertia ixx="0.145833" ixy="0.0" ixz="0.0" iyy="0.145833" iyz="0.0" izz="0.125" />
  </inertial>
</link>

<!-- right wheel joint -->
<joint name="${prefix}_wheel_joint" type="continuous">
  <origin xyz="${x} ${y} ${z}" rpy="-1.57 0 0" />  
  <parent link="${parent}" />
  <child link="${prefix}_wheel_link" />
  <axis xyz="0 0 1" />

  <dynamics damping="0.0" friction="0.2" />
</joint>

<gazebo reference="${prefix}_wheel_link">
  <material>Gazebo/Black</material>
  <mu1>0.7</mu1>
  <mu2>0.7</mu2>
</gazebo>



<link name="steering_link">
  <visual>
    <geometry>
      <box size="0.01 0.01 0.01" />
    </geometry>
  </visual>
  <inertial>
    <origin xyz="0 0 0" rpy="0 0 0" />
    <mass value="0.5" />
    <inertia ixx="0.1" ixy="0.0" ixz="0.0" iyy="0.1" iyz="0.0" izz="0.1" />
  </inertial>
</link>

<joint name="steering_joint" type="continuous">
  <origin xyz="1.75 0 0.115" rpy="0 0 0" />
  <parent link="${parent}" />
  <child link="steering_link" />
  <axis xyz="0 0 1" />
  <dynamics damping="0.5" friction="0.5" />
</joint>

<gazebo reference="steering_link">
    <material>Gazebo/Red</material>
  </gazebo>