mujoco

<mujoco model="PID Controllers">
  <size memory="10M"/>

  <visual>
    <headlight diffuse=".2 .2 .2"/>
    <global elevation="-30" />
  </visual>
  <statistic extent="0.50" />

  <extension>
    <plugin plugin="mujoco.pid">
      <!-- pure proportional gain, bounces up and down -->
      <instance name="pid1">
        <config key="kp" value="4.0"/>
      </instance>
      <!-- PD controller - settles below setpoint -->
      <instance name="pid2">
        <config key="kp" value="4.0"/>
        <config key="kd" value="0.4"/>
      </instance>
      <!-- PID controller - reaches setpoint -->
      <instance name="pid3">
        <config key="kp" value="4.0"/>
        <config key="ki" value="4"/>
        <config key="kd" value="0.4"/>
      </instance>
      <!-- PID controller with clamped I term. -->
      <instance name="pid4">
        <config key="kp" value="4.0"/>
        <config key="ki" value="4"/>
        <config key="kd" value="0.4"/>
        <config key="imax" value=".5"/>
      </instance>
    </plugin>
  </extension>

  <default>
    <geom type="sphere" size="0.01" rgba="1 1 1 1" />
  </default>

  <worldbody>
    <light pos="0.4 -.15 .6" dir="-1 .5 -1" diffuse=".7 .7 .7"/>
    <light pos="-.4 -.15 .6" dir="1 .5 -1" diffuse=".7 .7 .7"/>
    <geom name="floor" type="plane" pos="0 0 -0.1" size="0 0 100" />
    <body pos="-0.06 0 0">
      <joint name="j1" type="slide" axis="0 0 1" />
      <geom/>
    </body>
    <body pos="-0.02 0 0" >
      <joint name="j2" type="slide" axis="0 0 1" />
      <geom/>
    </body>
    <body pos="0.02 0 0" >
      <joint name="j3" type="slide" axis="0 0 1" />
      <geom/>
    </body>
    <body pos="0.06 0 0" >
      <joint name="j4" type="slide" axis="0 0 1" />
      <geom/>
    </body>
  </worldbody>
  <actuator>
    <plugin joint="j1" plugin="mujoco.pid" instance="pid1" ctrlrange="0 0.15" />
    <plugin joint="j2" plugin="mujoco.pid" instance="pid2" ctrlrange="0 0.15" />
    <plugin joint="j3" plugin="mujoco.pid" instance="pid3" ctrlrange="0 0.15" actdim="1" />
    <plugin joint="j4" plugin="mujoco.pid" instance="pid4" ctrlrange="0 0.15" actdim="1" />
  </actuator>
</mujoco>