Jiminy-py

The focus of the release was making the contact model more realistic in Jiminy. As a reminder, it is formulated at acceleration level instead of velocity-level with impulse contact forces. The contact solver has been revamped to improve convergence, to ensure isotropic coulomb friction cone, and to follow maximum energy dissipation principal (except during the short transient sliding/sticking, or for dominant non-linear acceleration effects such as Coriolis). Many long lasting bugs in C++ core and Python have been tracked down and fixed.

New features

* [core] Enforce isotropic solution for PGS. (467)
* [core] Compensate PGS bias to ensure maximum energy dissipation for tangential friction. (468)
* [python/viewer] Add 'frame' markers. (464)
* [gym/common] Add 'evaluate' method to evaluate a callback policy over a whole episode. (453)

Improvements

* [core] Compute PGS error in residual space. (462)
* [core] PGS skip parameter update if irrelevant. (464)
* [core] Force sensors now measure total external force applied on a body.
* [core] Split constraint and contact options. (462)
* [core] Move to next breakpoint if possible to avoid very small timesteps during integration. (464)
* [python/viewer] Add support of 'pin.SE3' object for marker pose. (465)
* [python/viewer] Support specifying marker orientation using rotation matrix. (464)

Patches and bug fixes

* [core] Fix non-linear PGS solving of friction cone. (461)
* [core] Fix 'removeContactPoints' if input vector is empty.
* [core] Fix timestep adjustment for fixed timestep euler explicit stepper. (464)
* [core] Fix baumgarte stabilization of orientation for 'FixedFrameConstraint'. (465)
* [core] Fix json dump for empty dictionary. (466)
* [core] Remove random permutation from PGS since preserving order is important. (467)
* [core] Fix 'JointConstraint' position difference not properly computed. (469)
* [core] Fix telemetry header to null terminate leading to segfault. (469)
* [core] Fix inconsistency between flexible model and data. (469)
* [python/log] Fix segfault when loading robot from log. (466)
* [python/viewer] Exception handling and timeout if backend recorder for meshcat fails to open. (452)
* [python/viewer] Avoid crashing when replying simulations with 'nan'. (458)
* [python/viewer] Fix extraction of available sensor data for replay. (463)
* [python/viewer] Keep floor hidden even if updated if it was previously hidden for panda3d backend. (463)
* [python/viewer] Fix 'display' method if velocity is not provided. (463)
* [python/viewer] Fix body selection for panda3d. (465)
* [python/viewer] Do not overwrite color for 'frame' marker by default. (464)
* [gym/common] Improve exception handling during 'step'. (458)
* [gym/common] Do not try to register action to telemetry if empty.
* [gym/envs] Reduce KD gain for AkY joints of Atlas to prevent numerical instability. (464)

Miscellaneous

* [core] Use 'impulse' contact model as default. (462)
* [core] Modify 'FixedFrameConstraint' to set ground normal instead of local rotation. (464)
* [core] Order 'FixedFrameConstraint' components by solving order. (467)
* [gym/common] Rename 'refresh_*' in 'initialize_' when appropriate. (466)
* [gym/common] Rename 'refresh_internal' in 'refresh_buffers' and add 'initialize_buffers' method. (466)
* [gym/envs] Automatically detect relevant contact points for Atlas. (464)
* [misc] Update python packages description and development status. (458)
* [misc] Run unit tests in debug mode on Ubuntu 20.04. (469)

Co-authored-by: Alexis Duburcq <alexis.duburcqgmail.com>

This release is mainly intended to improve the support of Mac OS X >= 10.14 (Mojave). Now it is on a par with other platforms, with CI configured to run the unit tests on it. It also fixes a bunch of bugs concerning the viewer and the import of jiminy_py itself for developer users.

Improvements

* [viewer] 'add_markers' now forward positional arguments.
* [viewer] Interrupt replay without crashing the display window for all backends.
* [misc] Significant wheels size reduction (~20Mo for each architecture now).
* [misc] Enable python unit tests on OSX.

Patches and bug fixes

* [core] Fix sphere constraint.
* [viewer] Fix meshcat port detection on OS X.
* [viewer] Disable physics-based shader is no discrete NVIDIA GPU to avoid graphic glitches. (448)
* [viewer] Force using 'spawn' multiprocessing context for meshcat to avoid crashes on OS X.
* [viewer] Fix 'ipykernel' version detection on some setups.
* [simulator] Fix wrong 'viewer.f_external' forces if render without simulation running.
* [misc] Fix import of jiminy if boost is installed on the system but not pinocchio/hppfcl/eigenpy.

Miscellaneous

* [misc] Fix warnings using 'clang' compilation toolchain.
* [misc] Build shared libs for boost python dependencies on unix to fix binding issues on OS X.
* [misc] Fix jiminy pywrap copied twice in OS X wheels.
* [misc] Build only universal2 wheel on OSX whenever possible.
* [misc] Fix desired chromium version used by pyppeteer being ignored.
* [misc] Update chromium version used by pyppeteer for the latest one available of any platform.
* [misc] Fix OS X wheels deployment on Pypi. (446)
* [misc] Upgrade python dependencies.

Some limitations of Jiminy have been addressed. First, the friction pyramid has been replaced by an actual friction cone for the impulse contact model. Secondly, it is now possible to simulate a flexible model and impulse contact without numerical instability by introducing a new armature-like inertia parameter. Next, the viewer now uses a physics-based shader for Panda3D backend and a bunch of display issues have been fixed. Finally, it is the first release to officially support OS X, including arm Apple M1 CPU. Pre-compiled binaries are distributed on pypi.

New features

* [core] Implement friction cone for impulse model. (440)
* [core] Fix numerical instability of flexibility model by adding armature-like inertia parameter. (433)
* [python/viewer] Add physic based rendering of materials to panda3d.
* [misc] Initial support of Mac (441)

Patches and improvements

* [core] Full support of armature for all joints but mimic.
* [python/viewer] Change direction of lighting in panda3d to fell natural for default camera pose.
* [python/viewer] Enhanced rendering in panda3d for discrete gpu.
* [python/viewer] Render meshes two-sided in panda3d to avoid seeing through them.
* [gym/rllib] Add option to forward keyword arguments to 'ray.init'. (436)

Bug fixes

* [python/robot] Fix default hardware config file generator is both collision and visual meshes are defined.
* [python/viewer] Fix shadow casting area smaller than floor in panda3d.
* [python/viewer] Fix window name not set properly in panda3d.

Miscellaneous

* [core] Rename 'pncCollisionData' to 'collisionData' and 'pncModelRigidOrig_' to 'pncModelOrig_'.
* [core] Fix some implicit type conversions.
* [misc] Update Python dependencies.
* [misc] Update Boost from 1.7.1 to 1.7.6.
* [misc] Build OSX wheels. (442)

The simulator and viewer is now compatible with robots created manually from scratch without relying on URDF. Additionally, PGS solver with default parameters is now much faster thinks to SIMD vectorization and lower accuracy. The provided Cassie and Atlas environment have been tuned to improve the real time factor, which is now close to 50 on a single core.

New features

* [core] Enable to initialize 'jiminy::Robot' pinocchio models directly..
* [python/robot] Enable to load hardware config on existing robot.
* [gym/envs] Add atlas env with fixed upper body.

Improvements

* [core] Faster PGS solver. (423)
* [core] Add dedicated contact solver options 'tolAbs', 'tolRel'. (424)
* [core] Add 'name' getter to 'jiminy::Model', which is a proxy for URDF name.
* [core] Add visual model to 'jiminy::Model' to avoid relying on URDF for rendering
* [core/python] Add helper method to build reduced model.
* [python] Do not rely on 'Robot.urdf_path' anymore.
* [python/robot] Check if motors and sensors defined in hardware file can be added successfully.
* [gym/common] Make sure the provided neutral configuration is valid.

Patches and bug fixes

* [core] Fix wrong computation of external forces.
* [python/dynamics] Fix 'compute_freeflyer_state_from_fixed_body' method if fixed body is not provided.

Miscellaneous

* [gym/envs] Tune Cassie and Atlas to improve numerical stability using impulse contact model.
* [misc] Fix support of matplotlib >= 3.4.
* [misc] Stricter gym_jiminy optional deps requirements. (425)
* [misc] Fix gym_jiminy wheels deployement on pypi (again!).
* [misc] Fix documentation generation.

Minor release mainly fixing bugs introduced recently.

New features

* [core] Add 'orientation' parameter 'randomTileGround' generator.

Improvements

* [gym/common] Render ground profile automatically during 'play_interactive'.

Patches and bug fixes

* [core/python] Fix python bindings of 'resetRandomGenerators' method.
* [core/python] Fix assert in debug.
* [python/simulation] Fix 'seed' method not resetting the generator if the seed does not change.
* [python/viewer] Close panda3d viewer cleanly.
* [gym/rllib] Fix PPO for 'enable_adversarial_noise' = False and 'caps_global_reg' == 0.0.

Miscellaneous

* [misc] Build wheels for manylinux2014 instead of manylinux2010 because of 'dm-tree'.
* [misc] Build in Release and Debug on Ubuntu CI.

<p align="center"> <img src="https://user-images.githubusercontent.com/17752950/137580144-15968b75-91ba-4b91-afec-52f09f5af8da.png" height="300"> </p>

Random terrain generation tools have been translated from Python to C++ to significantly improve efficiency. New utilities to merge and sum random tile ground has been added to generate feature-rich ground profiles without noticeable slowdown wrt flat ground. In addition, it has been made easier to register new variables to the telemetry dynamically and retrieve data from logfiles.

_Nota bene: gym_jiminy release were not deployed on pypi since 1.6.27. This problem has been fixed now but there is no plan to add back the missing ones._

New features

* [core] Add tools to merge and sum heightmaps.
* [gym/common] Add 'BaseJiminyEnv.register_variable' method easily log variables.
* [gym/rllib] Add adversarial obs perturbation sampling for spatial regularization. (414)

Improvements

* [core] Write terrain generation tools in C++ for efficiency.
* [core] Enable to re-initialize controllers.
* [core/python] It is now possible to extract raw python function from 'HeightMapFunctor' if any.
* [python/viewer] Faster ground profile rendering.
* [python/viewer] Do not render ground profile if original flat ground.
* [gym/common] Generic structured space handling by relying on 'dm-tree' package.
* [gym/common] Support any observation space in gym pipelines.

Miscellaneous

* [core] Rename 'HeatMap' in 'Heightmap'.
* [misc] Fix CI not pushing gym_jiminy wheels on pypi.