If given two non-decreasing values, `springlength` specifies a deadband for spring stiffness, inside of which the force is 0 and outside of which force behaves like a regular spring, with the setpoint corresponding to the nearest value. This can be used to create tendons whose limits are enforced by springs rather than constraints, which are cheaper and easier to analyse. See test/engine/testdata/tendon_springlength.xml example model.
Spring-limited spatial tendons whose lower range value is 0 are rendered as catenaries.
Fixes#520.
PiperOrigin-RevId: 484509706
Change-Id: I6698e94ee36168f52d501e83057559805e05172d
- Added new `cable` composite type:
* The `initial` parameter specifies the joint at the starting boundary: `free`, `ball`, or `none`.
* The boundary bodies are exposed with the names:`B_left` and `B_right`.
* The vertex initial positions can be specified directly in the XML with the parameter `vertex`.
* The orientation of the body frame **is** the orientation of the material frame of the curve.
- Added new `cable` passive force plugin:
* Twist and bending stiffness can be set separately with the parameters `twist` and `bend`.
* The stress-free configuration can be set to be the initial one or flat with the flag `flat`.
* New cable example showing the formation of plectoneme.
* New coil example.
* New belt example showing interaction between twist and anisotropy.
* Added test using cantilever exact solution.
PiperOrigin-RevId: 480033694
Change-Id: I491271bce8fccb185961477e903e5a72d172c8a3
This is an amendment to 4bfc2c0311.
Add an autolimits compiler option. When true, *limited will be inferred from the presence of the *range attributes.
When false, models where limited is not specified, and range is will fail to compile.
PiperOrigin-RevId: 472438650
Change-Id: I489098e879ee695030f44e0d8cd969787e75fb90
- Added `refsite` attribute to actuators with `site` transmission.
- Such actuators now have a well defined length and can be used for e.g., Cartesian end-effector control.
- Added example models and documentation describing the new feature.
PiperOrigin-RevId: 471561218
Change-Id: I538f09af9600d5c53992c4a9fed325648aab4fa3
- `anchor` determines the point of wrench application, in the frame of body2.
- `tfratio` scales applied torques relative to applied forces.
- Add visualisation of both anchor points to both weld and connect constraints.
- Add a test model showing how the new weld parameters behave.
PiperOrigin-RevId: 470021901
Change-Id: I3faba0e5dcab2e29ee81096f5ff71ff66d99758c
- `anchor` determines the point of wrench application, in the frame of body2.
- `tfratio` scales applied torques relative to applied forces.
- Add visualisation of both anchor points to both weld and connect constraints.
- Add a test model showing how the new weld parameters behave.
PiperOrigin-RevId: 469228149
Change-Id: I836b0791f10fb624607a12ef3c687da991c21789
- `anchor` determines the point of wrench application, in the frame of body2.
- `tfratio` scales applied torques relative to applied forces.
- Add visualisation of both anchor points to both weld and connect constraints.
- Add a test model showing how the new weld parameters behave.
PiperOrigin-RevId: 469190483
Change-Id: I20f6da85b09cd2c4c0b5d29eb8003eabb524e55e
- Adhesion actuators using contact normals as force transmission mechanism.
- Related video: https://youtu.be/HdBue4MUZysCloses#229
PiperOrigin-RevId: 464389367
Change-Id: I9f69b3cd152d957e8f65870d208788463c036a6d
- Mesh inertias can now be computed exactly for well-formed (no holes) non-convex meshes.
- To activate this feature, set `<compiler exactmeshinertia="true">` (defaults to `false`). This default may change in the future.
- Added `<geom shellinertia="true/false">` (defaults to `false`). When true, geom inertia is computed assuming all the mass is concentrated on the surface, and `density` is interpreted as surface density (mass/area). Currently only mesh geoms are supported.
PiperOrigin-RevId: 464368395
Change-Id: I17afd99b9b221c9d24ae951f6e63d5c61ff89820
- Add basic test for keyframes.
- Add missing documentation for keyframe mocap positions and quaternions.
PiperOrigin-RevId: 459021649
Change-Id: I91cf7ecbddc6262e8c72a868eeb82d627f389fb3
- Applies to [orientation specifiers](https://mujoco.readthedocs.io/en/latest/modeling.html#frame-orientations) in `body`, `inertial`, `geom`, `site`, `camera`.
- Before this change the check was done only for multiple *alternative* specifiers, but not for `quat` and an alternative specifier.
- Moved the check from the compiler to the parser.
- Added tests.
PiperOrigin-RevId: 453201981
Change-Id: I20907361f211dae904e734cd083e9df0efe4f654
Yuval Tassa