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 Copyright (c) 2020, Fabio Muratore, Honda Research Institute Europe GmbH, and
 Technical University of Darmstadt.
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    or Technical University of Darmstadt, nor the names of its contributors may
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-->

<!-- Cheetah Model
    The state space is populated with joints in the order that they are
    defined in this file. The actuators also operate on joints.

    State-Space (name/joint/parameter):
        - rootx     slider      position (m)
        - rootz     slider      position (m)
        - rooty     hinge       angle (rad)
        - bthigh    hinge       angle (rad)
        - bshin     hinge       angle (rad)
        - bfoot     hinge       angle (rad)
        - fthigh    hinge       angle (rad)
        - fshin     hinge       angle (rad)
        - ffoot     hinge       angle (rad)
        - rootx     slider      velocity (m/s)
        - rootz     slider      velocity (m/s)
        - rooty     hinge       angular velocity (rad/s)
        - bthigh    hinge       angular velocity (rad/s)
        - bshin     hinge       angular velocity (rad/s)
        - bfoot     hinge       angular velocity (rad/s)
        - fthigh    hinge       angular velocity (rad/s)
        - fshin     hinge       angular velocity (rad/s)
        - ffoot     hinge       angular velocity (rad/s)

    Actuators (name/actuator/parameter):
        - bthigh    hinge       torque (N m)
        - bshin     hinge       torque (N m)
        - bfoot     hinge       torque (N m)
        - fthigh    hinge       torque (N m)
        - fshin     hinge       torque (N m)
        - ffoot     hinge       torque (N m)
-->
<mujoco model="cheetah">
  <compiler angle="radian" coordinate="local" inertiafromgeom="true" settotalmass="[total_mass]" texturedir="[ASSETS_DIR]/textures"/>
  <size nstack="300000" nuser_geom="1"/>
  <option gravity="0 0 -9.81" timestep="0.01"/>

  <default>
    <joint armature=".1" damping=".01" limited="true" solimplimit="0 .8 .03" solreflimit=".02 1" stiffness="8"/>
    <geom conaffinity="0" condim="3" contype="1" friction="[tangential_friction_coeff] [torsional_friction_coeff] [rolling_friction_coeff]" rgba="0.8 0.6 .4 1" solimp="0.0 0.8 0.01" solref="0.02 1"/>
    <motor ctrllimited="true" ctrlrange="-1 1"/>
  </default>

  <visual>
    <rgba fog="1. 1. 1. 1."/>
    <map fogstart="2" fogend="4"/>
    <quality shadowsize="4096"/>
  </visual>

  <asset>
    <texture name="sky" type="skybox" builtin="flat" rgb2="1. 1. 1." height="2048" width="2048"/>
    <texture builtin="flat" height="1278" mark="cross" markrgb="1 1 1" name="texgeom" random="0.01" rgb1="0.8 0.6 0.4" rgb2="0.8 0.6 0.4" type="cube" width="127"/>
    <texture name="texplane" type="2d" file="IAS_floor.png" width="4096" height="4096"/>
    <material name="matplane" reflectance="0.3" shininess="1" specular="1" texture="texplane" texrepeat="10 10"/>
    <material name="geom" texture="texgeom" texuniform="true"/>
  </asset>

  <worldbody>
    <light cutoff="100" diffuse="1 1 1" dir="-0 0 -1.3" directional="true" exponent="1" pos="0 0 1.3" specular=".1 .1 .1"/>

    <geom name="floor" conaffinity="1" condim="3" material="matplane" pos="0 0 0" rgba="0.8 0.9 0.8 1" size="40 40 0.125" type="plane"/>
    
    <body name="torso" pos="0 0 .7">
      <camera name="track" mode="trackcom" pos="0 -3 0.3" xyaxes="1 0 0 0 0 1"/>
      <joint armature="0" axis="1 0 0" damping="0" limited="false" name="rootx" pos="0 0 0" stiffness="0" type="slide"/>
      <joint armature="0" axis="0 0 1" damping="0" limited="false" name="rootz" pos="0 0 0" stiffness="0" type="slide"/>
      <joint armature="0" axis="0 1 0" damping="0" limited="false" name="rooty" pos="0 0 0" stiffness="0" type="hinge"/>
      <geom fromto="-.5 0 0 .5 0 0" name="torso" size="0.046" type="capsule"/>
      <geom axisangle="0 1 0 .87" name="head" pos=".6 0 .1" size="0.046 .15" type="capsule"/>
      <!-- <site name='tip'  pos='.15 0 .11'/>-->
      <body name="bthigh" pos="-.5 0 0">
        <joint axis="0 1 0" damping="6" name="bthigh" pos="0 0 0" range="-.52 1.05" stiffness="240" type="hinge"/>
        <geom axisangle="0 1 0 -3.8" name="bthigh" pos=".1 0 -.13" size="0.046 .145" type="capsule"/>
        <body name="bshin" pos=".16 0 -.25">
          <joint axis="0 1 0" damping="4.5" name="bshin" pos="0 0 0" range="-.785 .785" stiffness="180" type="hinge"/>
          <geom axisangle="0 1 0 -2.03" name="bshin" pos="-.14 0 -.07" rgba="0.9 0.6 0.6 1" size="0.046 .15" type="capsule"/>
          <body name="bfoot" pos="-.28 0 -.14">
            <joint axis="0 1 0" damping="3" name="bfoot" pos="0 0 0" range="-.4 .785" stiffness="120" type="hinge"/>
            <geom axisangle="0 1 0 -.27" name="bfoot" pos=".03 0 -.097" rgba="0.9 0.6 0.6 1" size="0.046 .094" type="capsule"/>
          </body>
        </body>
      </body>
      <body name="fthigh" pos=".5 0 0">
        <joint axis="0 1 0" damping="4.5" name="fthigh" pos="0 0 0" range="-1 .7" stiffness="180" type="hinge"/>
        <geom axisangle="0 1 0 .52" name="fthigh" pos="-.07 0 -.12" size="0.046 .133" type="capsule"/>
        <body name="fshin" pos="-.14 0 -.24">
          <joint axis="0 1 0" damping="3" name="fshin" pos="0 0 0" range="-1.2 .87" stiffness="120" type="hinge"/>
          <geom axisangle="0 1 0 -.6" name="fshin" pos=".065 0 -.09" rgba="0.9 0.6 0.6 1" size="0.046 .106" type="capsule"/>
          <body name="ffoot" pos=".13 0 -.18">
            <joint axis="0 1 0" damping="1.5" name="ffoot" pos="0 0 0" range="-.5 .5" stiffness="60" type="hinge"/>
            <geom axisangle="0 1 0 -.6" name="ffoot" pos=".045 0 -.07" rgba="0.9 0.6 0.6 1" size="0.046 .07" type="capsule"/>
          </body>
        </body>
      </body>
    </body>
  </worldbody>

  <actuator>
    <motor gear="120" joint="bthigh" name="bthigh"/>
    <motor gear="90" joint="bshin" name="bshin"/>
    <motor gear="60" joint="bfoot" name="bfoot"/>
    <motor gear="120" joint="fthigh" name="fthigh"/>
    <motor gear="60" joint="fshin" name="fshin"/>
    <motor gear="30" joint="ffoot" name="ffoot"/>
  </actuator>
</mujoco>