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Add support for excluded contacts in adhesion actuators.

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- Update example model.
- Update video.

PiperOrigin-RevId: 468464196
Change-Id: I603c5a89c2d5a736de127440e6d542beffc12583
This commit is contained in:
Yuval Tassa
2022-08-18 08:27:42 -07:00
committed by Copybara-Service
parent 4bfc2c0311
commit 833dc74074
4 changed files with 111 additions and 50 deletions
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model/adhesion/active_adhesion.xml
+17 -16
View File
@@ -1,4 +1,8 @@
<mujoco model="Active adhesion example">
<!--
Adding some fluid viscosity to prevent the hanging sphere from jiggling too much.
-->
<option viscosity="1"/>
<size nconmax="500" njmax="1000"/>
@@ -8,12 +12,7 @@
<default>
<joint damping=".3" axis="0 1 0"/>
<!--
By adding 3mm of margin yet making solimp barely apply any force until 3mm penetration, we get
3mm of "action at a distance". This is important so that small changes in distance don't lead
to loss of adhesion
-->
<geom type="box" friction=".5" margin=".003" solimp="0 .99 .003 .9 6"/>
<geom type="box" friction=".5"/>
<default class="wall">
<geom rgba=".5 .5 .5 .4"/>
</default>
@@ -22,7 +21,12 @@
<tendon rgba=".5 .5 .8 1"/>
</default>
<default class="active_adhesion">
<geom rgba=".8 .5 .5 1"/>
<!--
Geoms in the active_adhesion class are "inflated" with a margin of 1cm, but contacts are
activated only at a depth gap of 1cm, leading to a layer of inactive contacts at a 1cm
distance from the surface. However the contacts can be used by the adhesion actuator.
-->
<geom rgba=".8 .5 .5 1" margin=".01" gap=".01"/>
</default>
<default class="object">
<geom rgba=".5 .8 .5 1" density="100"/>
@@ -77,18 +81,15 @@
<site name="hook_left" pos=".08 0 .3"/>
<site name="hook_right" pos=".12 0 .3"/>
<body name="sphere" pos=".1 0 .2" childclass="active_adhesion">
<!--
Note we are adding damping to a free joint. This is an easy yet unphysical way to prevent
the sphere from jiggling too much on the winch tendons. An alternative would be to add fluid
density or viscosity.
-->
<joint type="free" damping=".1"/>
<freejoint/>
<!--
The composite balls in the crate have only 3 linear DoFs with condim=1, effectively
frictionless point particles. In order to make them stick to the sphere we give the sphere
priority 2, to force condim=3.
Also note the sphere has a margin+gap of 3cm as opposed to the 1cm of the arm box.
-->
<geom type="sphere" size=".03" priority="2"/>
<geom type="sphere" size=".03" priority="2" margin=".03" gap=".03"/>
<site name="pin_left" pos="-.025 0 .025"/>
<site name="pin_right" pos=".025 0 .025"/>
</body>
@@ -127,9 +128,9 @@
<actuator>
<position name="conveyor" joint="conveyor" ctrlrange="-.2 .2" ctrllimited="true" kp="400"/>
<position name="arm" joint="arm2" ctrlrange="-.8 1" ctrllimited="true" kp="10"/>
<adhesion name="adhere_arm" body="4boxes" ctrlrange="0 1" gain="20"/>
<adhesion name="adhere_arm" body="4boxes" ctrlrange="0 1" gain="5"/>
<position name="winch" joint="winch" ctrlrange="-.7 .5" ctrllimited="true" kp="10"/>
<adhesion name="adhere_winch" body="sphere" ctrlrange="0 1" gain="20"/>
<adhesion name="adhere_winch" body="sphere" ctrlrange="0 1" gain="5"/>
</actuator>
<sensor>