How to add a normal motor to gazebo_sitl

Ioannis_Mandralis · May 22, 2023, 8:45pm

Hi everyone,

I am trying to add a normal motor to a robot I am developing in Gazebo SITL. I have seen the libgazebo_motor_model.so plugin, but I don’t think this works for my purposes since this motor model also produces a thrust and drag moment i.e. it is the motor model for spinning propellers.

I just want a normal motor that can spin a joint. How can I specify something like this and connect it through to the firmware through the airframe ?

Thanks for any input

Best regards,
Ioannis Mandralis

JulianOes · May 22, 2023, 9:50pm

You can have a look how the gimbal of the Typhoon H480 model is made. I believe it uses some sort of motor on a joint:

github.com

PX4/PX4-SITL_gazebo-classic/blob/9bfecb66734de395e44a2ade6bcd2e0321cf0472/models/typhoon_h480/typhoon_h480.sdf.jinja#L183


      
                </mesh>
              </geometry>
              <material>
                <script>
                  <name>Gazebo/DarkGrey</name>
                  <uri>file://media/materials/scripts/gazebo.material</uri>
                </script>
              </material>
            </visual>
          </link>
          <joint name='cgo3_mount_joint' type='revolute'>
            <child>cgo3_mount_link</child>
            <parent>base_link</parent>
            <pose>0 0 0 0 0 0</pose>
            <axis>
              <xyz>0 0 1</xyz>
              <limit>
                <lower>0</lower>
                <upper>0</upper>
                <effort>100</effort>
                <velocity>-1</velocity>

Ioannis_Mandralis · May 22, 2023, 10:50pm

Thank you very much for your response. However, I think this is for a gimbal joint. I only want to rotate the joint in one axis. Do you know how this could be done ?

Best,
Ioannis

Francisco_Toapanta · September 11, 2023, 6:28pm

You can follow this idea:

<joint name='rotor_puller_joint' type='revolute'>
      <child>rotor_puller</child>
      <parent>base_link</parent>
      <axis>
        <xyz>1 0 0</xyz>
        <limit>
          <lower>-1e+16</lower>
          <upper>1e+16</upper>
        </limit>
        <dynamics>
          <spring_reference>0</spring_reference>
          <spring_stiffness>0</spring_stiffness>
        </dynamics>
        <use_parent_model_frame>1</use_parent_model_frame>
      </axis>
    </joint>

with this, you are going to have a rotation joint