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Add implicit integrator.

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Added analytic derivatives of smooth (unconstrained) dynamics forces, with respect to velocities:
  - Centripetal and Coriolis forces computed by the Recursive Newton-Euler algorithm.
  - Damping and fluid-drag passive forces.
  - Actuation forces.

A new implicit-in-velocity integrator is implemented using the analytic derivatives. This integrator lies between the Euler and Runge Kutta integrators in terms of both stability and computational cost.

PiperOrigin-RevId: 450377010
Change-Id: Ie192b441876c22e732fb749333926f296e0a09cc
This commit is contained in:
DeepMind
2022-05-23 01:21:24 -07:00
committed by Copybara-Service
parent 1913a02b40
commit 64bc6d27b2
30 changed files with 1974 additions and 51 deletions
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doc/changelog.rst
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@@ -29,7 +29,18 @@ Open Sourcing
General
^^^^^^^
3. Added :at:`actlimited` and :at:`actrange` attributes to :ref:`general actuators<general>`, for clamping actuator
3. Added analytic derivatives of smooth (unconstrained) dynamics forces, with respect to velocities:
- Centripetal and Coriolis forces computed by the Recursive Newton-Euler algorithm.
- Damping and fluid-drag passive forces.
- Actuation forces.
#. Added ``implicit`` integrator. Using the analytic derivatives above, a new implicit-in-velocity integrator was added.
This integrator lies between the Euler and Runge Kutta integrators in terms of both stability and computational
cost. It is most useful for models which use fluid drag (e.g. for flying or swimming) and for models which use
:ref:`velocity actuators<velocity>`. For more details, see the :ref:`Numerical Integration<geIntegration>` section.
#. Added :at:`actlimited` and :at:`actrange` attributes to :ref:`general actuators<general>`, for clamping actuator
internal states (activations). This clamping is useful for integrated-velocity actuators, see the :ref:`Activation
clamping <CActRange>` section for details.
@@ -47,16 +58,15 @@ General
Bug fixes
^^^^^^^^^
10. Antialiasing was disabled for segmentation rendering. Before this change, if the :ref:`offsamples<quality>`
attribute was greater than 0 (the default value is 4), pixels that overlapped with multiple geoms would receive
averaged segmentation IDs, leading to incorrect or non-existant IDs. After this change :at:`offsamples` is ignored
during segmentation rendering.
8. Antialiasing was disabled for segmentation rendering. Before this change, if the :ref:`offsamples<quality>`
attribute was greater than 0 (the default value is 4), pixels that overlapped with multiple geoms would receive
averaged segmentation IDs, leading to incorrect or non-existant IDs. After this change :at:`offsamples` is ignored
during segmentation rendering.
#. The value of the enable flag for the experimental multiCCD feature was made sequential with other enable flags.
Sequentiality is assumed in the ``simulate`` UI and elsewhere.
#. The value of the enable flag for the experimental multiCCD feature was made sequential with other enable flags.
Sequentiality is assumed in the ``simulate`` UI and elsewhere.
#. Fix issue of duplicated meshes when saving models with OBJ meshes using mj_saveLastXML.
#. Fix issue of duplicated meshes when saving models with OBJ meshes using mj_saveLastXML.
Version 2.1.5 (Apr. 13, 2022)