These bodies have `body_invweight0 == 0` (infinite mass) and no degrees of freedom (identically 0 Jacobians). This was breaking some assumptions of the perturbation code which assumed perturbation applied only to moving bodies and led to very large forces/torques being applied. While these huge forces had no effect on the dynamics, they were reported by sensors, leading to unreasonable sensor readings.
PiperOrigin-RevId: 614398354
Change-Id: If5efe1c9e57e2be28af33d109679db8b3129da7f
Also:
- Renamed recently introduced `mjvPerturb` member `reflocalpos` -> `refselpos` and corrected docstring.
- Added `mjvPerturb.localmass`: body spatial inertia at selection point.
- Removed `const` qualifier to `mjData` argument of `mjv_initPerturb()`, to facilitate spatial inertia computation.
- Improved `mj_Object{Velocity, Acceleration}` docstrings, clarifying that rotational velocities precede linear velocities.
- Removed redundant const qualifiers from non pointer arguments to `mju_dot` and `mju_writeNumBytes`.
PiperOrigin-RevId: 511002168
Change-Id: I27400f497947f330072d4abb7c9bf7e71e6c5d49
Since fdbbc8bbe0, mju_mulQuat allows in-place computations.
There were a few places where the result was unnecessarily assigned to a temporary variable.
PiperOrigin-RevId: 477746005
Change-Id: I7351ef4796e7d70a4a54b930037bfaadee781f12
Yuval Tassa