Using Cable Composite to create a Pulley #1957
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parthos86
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Have you tried using an equality constraint with a tendon? |
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Thanks for the suggestion, I just tried equality constraint however i'm unable to understand why is the system unstable? As the both the bodies on either sides of the pulley are of the same mass and type, i would expect them both to stay in a state of equilibrium. Any input to fix this would greatly help me! Thanks minimal XML<mujoco model="test">
<compiler angle="radian" autolimits="true"/>
<option>
<flag sensor="enable"/>
</option>
<visual>
<headlight diffuse="0.7 0.7 0.7"/>
</visual>
<default class="main">
<joint limited="true" solimplimit="0.95 0.95 0.1 0.5 2" range="0 60"/>
<geom size="0.01 0 0" rgba="0.9 0.7 0.1 1"/>
<site rgba="0.9 0.9 0.9 1"/>
</default>
<asset>
<texture type="2d" name="checks1" builtin="checker" rgb1="1 1 1" rgb2="0 0 0" width="256" height="256"/>
<material name="test_color" texture="checks1" texuniform="true" texrepeat="2 2"/>
</asset>
<worldbody>
<site name="s2" pos="-0.03 0 0.32"/>
<body pos="-0.05 0 0.32" gravcomp="0">
<joint name="t1" pos="0 0 -0.02" axis="0 0 1" limited="false" type="slide"/>
<geom size="0.03" pos="0 0 -0.32" mass="1" rgba="0.2 0.2 0.5 1"/>
<site name="s1" pos="0 0 -0.32"/>
</body>
<body pos="0 0 0.3" quat="0.707107 -0.707107 0 0" gravcomp="0">
<joint name="Pulley" pos="0 0 0" axis="0 0 1" range="0 1.0472"/>
<geom name="g1" size="0.02 0.015" type="cylinder" material="test_color" rgba="0.3 0.9 0.3 0.4"/>
<site name="side1" pos="0 -0.03 0" quat="0.707107 0.707107 0 0"/>
</body>
<body name="tes" pos="0.05 0 0.32" gravcomp="0">
<joint name="t3" pos="0 0 -0.02" axis="0 0 1" limited="false" type="slide"/>
<geom size="0.03" pos="0 0 -0.32" mass="1" rgba="0.2 0.2 0.5 1"/>
<site name="s3" pos="0 0 -0.32"/>
</body>
</worldbody>
<equality>
<tendon tendon1="tendon1" polycoef="0 1 0 0 0"/>
</equality>
<tendon>
<spatial name="tendon1" damping="100" frictionloss="100" width="0.002" rgba="0.95 0.3 0.3 1">
<site site="s1"/>
<site site="s2"/>
<geom geom="g1" sidesite="side1"/>
<site site="s3"/>
</spatial>
</tendon>
<sensor>
<tendonpos tendon="tendon1" name="rope_length"/>
</sensor>
</mujoco>
Here is a video, illustrating my question: pulley_simulation.mp4 |
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Hi,
I'm a student and new to MuJoCo, I'm trying to use MuJoCo for simulating certain setups, that commonly occur in high school physics courses.
I'm looking for some help with using Cable Composite to create Pulleys and Movable Pulleys.
Currently there are a lot of examples, while using Tendons to create Pulleys. However as Tendons are extensible, they are not appropriate for my task.
I would like to go about converting the tendon in the below XML into a cable, However as far as i understand, cable Composite cannot be connected to sites, the way spatial tendon is connected to the arm via
sidesite="right"in the below example. I'm not sure how to go about doing this via a Cable. Any help would be greatly appreciated.minimal XML
Here is a video, illustrating my question:
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