data/model/plugin/elasticity/belt.xml

<!-- Copyright 2021 DeepMind Technologies Limited

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

         http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<mujoco model="Belt">
  <include file="scene.xml"/>

  <extension>
    <plugin plugin="mujoco.elasticity.cable"/>
  </extension>

  <statistic center="0 0 .2" extent="1"/>

  <visual>
    <global elevation="-30"/>
  </visual>

  <option timestep="0.001">
    <flag gravity="disable"/>
  </option>
  <compiler autolimits="true"/>

  <worldbody>
    <composite type="cable" offset="-.5 0 .05" initial="none"
      vertex="
      0.    0.   0.
      0.05  0.   0.05
      0.1   0.   0.1
      0.15  0.   0.15
      0.2   0.   0.2
      0.25  0.   0.25
      0.3   0.   0.3
      0.35  0.   0.35
      0.4   0.   0.4
      0.45  0.   0.45
      0.5   0.   0.5
      0.55  0.   0.45
      0.6   0.   0.4
      0.65  0.   0.35
      0.7   0.   0.3
      0.75  0.   0.25
      0.8   0.   0.2
      0.85  0.   0.15
      0.9   0.   0.1
      0.95  0.   0.05
      1.0   0.   0.  ">
      <plugin plugin="mujoco.elasticity.cable">
        <!--Units are in Pa (SI)-->
        <config key="twist" value="1e8"/>
        <config key="bend" value="1e7"/>
        <config key="vmax" value="0.2"/>
      </plugin>
      <joint kind="main" damping="0.1"/>
      <geom type="box" size="0.03535533906 0.02 0.0015" rgba=".8 .2 .1 1" group="3"/>
      <skin subgrid="3"/>
    </composite>
  </worldbody>

  <equality>
    <connect name="right_boundary" body1="B_last" anchor="0.07 0 0"/>
  </equality>

  <actuator>
    <motor site="S_last" gear="0 0 0 1 0 0" ctrlrange="-.2 .2"/>
  </actuator>
</mujoco>