bb87928bce
Upstream: https://github.com/Rhoban/onshape-to-robot Upstream-Commit: 80e710700aac9573a2230f74f7ce9e094833a0bc Upstream-Branch: master
145 lines
5.3 KiB
ReStructuredText
145 lines
5.3 KiB
ReStructuredText
.. _exporter-mujoco:
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MuJoCo
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======
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Introduction
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-------------
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MuJoCo is a standard physics simulator, coming with an extensive description format.
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* Frames will be added as ``site`` tags in the MuJoCo XML file.
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* *Actuators* will be created for all actuated joints (see below).
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* When :ref:`kinematic loops <kinematic-loops>` are present, they will be enforced using equality constraints.
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* If the loop is achieved using a ``fixed`` connector, a ``weld`` constraint will be added.
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* If a ``ball`` joint is used, a ``connect`` constraint will be added
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* If a ``revolute`` joint is used, two ``connect`` constraints will be used
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* Additionally to the ``robot.xml`` file, a ``scene.xml`` file will be produced, adding floor and lighting useful for testing purpose.
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``config.json`` entries (MuJoCo)
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--------------------------------
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Here is an example of complete ``config.json`` file, with details below:
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.. code-block:: javascript
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{
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"url": "document-url",
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"output_format": "mujoco",
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// ...
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// General import options (see config.json documentation)
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// ...
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// Additional XML file to be included in the URDF (default: "")
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"additional_xml": "my_custom_file.xml",
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// Override joint properties (default: {})
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"joint_properties": {
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// Default properties for all joints
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"*": {
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"actuated": true,
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"forcerange": 10.0,
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"frictionloss": 0.5,
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"limits": [0.5, 1.2]
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// ...
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},
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// Set the properties for a specific joint
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"joint_name": {
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"forcerange": 20.0,
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"frictionloss": 0.1
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// ...
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}
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},
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// Override geometry properties (default: {})
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"geom_properties": {
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// Set properties for specific links using pattern matching
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"foot": {
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"collision": {
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"name": "left_foot_collision",
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"friction": "1.2 0.005 0.0001"
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}
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},
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// Wildcard patterns are supported
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"leg_*": {
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"collision": {
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"solimp": "0.9 0.95 0.001",
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"solref": "0.02 1"
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},
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"visual": {
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"rgba": "1 0 0 1"
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}
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}
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},
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// Override equality attributes
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"equalities": {
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"closing_branch*": {
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"solref": "0.002 1",
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"solimp": "0.99 0.999 0.0005 0.5 2"
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}
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}
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}
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``joint_properties`` *(default: {})*
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Allow to specify the properties of the joints produced in the URDF output. The key should be joint names. The special ``default`` key will set default values for each joints.
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Possible values are:
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* ``actuated``: *(default: true)* whether an actuator should be associated to this joint,
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* ``class``: a ``class="..."`` to be added to the joint (and actuator)
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* ``type`` *(default: position)* defines the actuator that will be produced
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* ``range`` *(default: true)*: if ``true``, the joint limits are reflected on the joint ``range`` attribute
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* ``limits``: Override the joint limits, should be a list of two values (min, max)
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* The following are reflected as ``<joint ...>`` attributes:
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* ``frictionloss``
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* ``damping``
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* ``armature``
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* ``stiffness``
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* The following are reflected as actuator (``<position ...>`` or other) attributes:
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* ``kp``, ``kv`` and ``dampratio`` gains
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* ``forcerange``
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``geom_properties`` *(default: {})*
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Allow to specify the properties of the geometries (collision and visual) produced in the MuJoCo output. The key should be part names with support for wildcard pattern matching.
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Properties can be specified separately for ``visual`` and ``collision`` geometries, or applied to both if not nested.
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Wildcard patterns (``*``, ``?``, ``[seq]``) are supported for matching part names. When multiple patterns match, properties are merged in order with later matches overriding earlier ones.
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All properties are added as XML attributes to the ``<geom ...>`` tag. Common MuJoCo geom attributes include:
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* ``name``: Override the geometry name
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* ``friction``: Friction coefficients (e.g., ``"1.2 0.005 0.0001"``)
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* ``solimp``: Solver impedance parameters (e.g., ``"0.9 0.95 0.001"``)
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* ``solref``: Solver reference parameters (e.g., ``"0.02 1"``)
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* ``contype``: Contact type bitmask (e.g., ``"1"``)
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* ``conaffinity``: Contact affinity bitmask (e.g., ``"1"``)
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* ``rgba``: Color and transparency (e.g., ``"1 0 0 1"``)
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``equalities`` *(default: {})*
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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This entry allows to override the equality attributes of the MuJoCo XML file. The key should be the equality name (which might contains wildcards ``*``), and the value should be a dictionary of attributes.
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This can be used to adjust the ``solref`` and ``solimp`` attributes of the equality constraints.
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``additional_xml`` *(default: "")*
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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If you want to include additional XML in the URDF, you can specify the path to the file here. This file will be included in the produced XML.
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.. note::
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Alternatively, ``additional_xml`` can be a list of files
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