Improvements related to models where joint-actuator relationship is not one-to-one:

- Add `joint-actuatorforcerange` for clamping total actuator force at joints. Add `sensor-jointactuatorfrc` for sensing total actuator forces on a single joint. See [documentation](https://mujoco.readthedocs.io/en/latest//modeling.html#actuator-force-clamping) for justification and use cases. - Add simple car model to `model/`. - Move actuation-related test models into `engine/testdata/actuation/`. PiperOrigin-RevId: 549355941 Change-Id: I27f6c1f80426d73a2811ef5ae74684a228b2fbd1
2023-07-19 10:28:24 -07:00
parent 7603b07a20
commit 51aa375af0
29 changed files with 453 additions and 105 deletions
@@ -1,5 +1,8 @@
 <mujoco>
-  <compiler autolimits="true" />
+  <compiler autolimits="true"/>
+
+  <option integrator="implicitfast"/>
+
  <worldbody>
    <geom type="plane" size="1 1 .01"/>
    <light pos="0 0 2"/>
@@ -0,0 +1,26 @@
+<mujoco>
+  <compiler autolimits="true"/>
+
+  <option integrator="implicitfast"/>
+
+  <worldbody>
+    <geom type="plane" size="1 1 .01"/>
+    <light pos="0 0 2"/>
+    <body pos="0 0 .3">
+      <joint name="hinge" damping=".01" actuatorforcerange="-.4 .4"/>
+      <geom type="capsule" size=".01" fromto="0 0 0 .2 0 0"/>
+      <geom size=".03" pos=".2 0 0"/>
+    </body>
+  </worldbody>
+
+  <actuator>
+    <motor name="motor" joint="hinge" ctrlrange="-1 1"/>
+    <damper name="damper" joint="hinge" kv="10" ctrlrange="0 1"/>
+  </actuator>
+
+  <sensor>
+    <actuatorfrc name="motor" actuator="motor"/>
+    <actuatorfrc name="damper" actuator="damper"/>
+    <jointactuatorfrc name="hinge" joint="hinge"/>
+  </sensor>
+</mujoco>
@@ -24,7 +24,12 @@
      -->
      <general gainprm=".5" biasprm="0 -.5 -.05" biastype="affine" ctrlrange="-1.571 1.571"/>
    </default>
-    <joint damping="1e-4"/>
+    <!--
+    Clamping the total actuator torque at the joints means that the motion produced by the Cartesian
+    commands is achievable by individual joint actuators with the specified torque limits.
+    See https://mujoco.readthedocs.io/en/latest//modeling.html#actuator-force-clamping
+    -->
+    <joint stiffness="1e-1" actuatorforcerange="-1 1"/>
    <site type="box" size=".012 .012 .012" rgba=".7 .7 .8 1"/>
  </default>

@@ -33,16 +38,21 @@
    <geom type="box" size=".25 .25 .01" pos="0 0 -.01"/>
    <site name="reference" pos="0 0 .25"/>
    <body name="arm" pos="-.25 .25 0">
-      <joint type="ball"/>
+      <joint axis="1 0 0"/>
+      <joint axis="0 1 0"/>
      <geom type="box" size=".01" fromto="0 0 0 0 0 .25"/>
      <body pos="0 0 .25">
-        <joint type="ball"/>
+        <joint axis="0 1 0"/>
+        <joint axis="0 0 1"/>
        <geom type="box" size=".01" fromto="0 0 0 .25 0 0"/>
        <body pos=".25 0 0">
-          <joint type="ball"/>
+          <joint axis="1 0 0"/>
+          <joint axis="0 0 1"/>
          <geom type="box" size=".01" fromto="0 0 0 0 -.2 0"/>
          <body pos="0 -.2 0">
-            <joint type="ball"/>
+            <joint axis="1 0 0"/>
+            <joint axis="0 0 1"/>
+            <joint axis="0 1 0"/>
            <geom type="box" size=".01" fromto="0 0 0 0 -.05 0"/>
            <site name="end_effector" pos="0 -.05 0"/>
          </body>