https://youtu.be/17XpwnqyCXs
New transmission type mjTRN_SO3: a relative orientation, targeting a ball
joint or a site+refsite pair. It is the first transmission with more than
one force output: its length is the norm of the expmap vector of the
relative rotation and its moment axes are the 3 rows of the
relative rotational Jacobian, without projecting onto per-actuator gears.
New force law mjGAIN_SO3/mjBIAS_SO3: a geodesic PD servo, force =
kp * log(q_current^-1 * q_target) - kv * velocity, exact for arbitrary axis
combinations with a unique equilibrium at every commanded orientation.
Error, moment rows and velocity all live in the child frame (joint or
site): the right-difference error is the gradient of the geodesic
potential in that frame. The parent-frame (left) error is not: driving
child-frame torques with it pumps energy at large angles, settling into
steady-spinning limit cycles (the SO3LargeAngleConvergence test). The
integrator variant stores the 3D orientation setpoint in act (actnum = 3,
re-anchored to a bounded representative at integration time). Exposed in
MJCF as <orientation joint=|site=+refsite= kp kv|dampratio>, or via
<general gaintype="so3" biastype="so3">.
The setpoint input has two charts: an expmap target (3 controls, default)
or a quaternion target (4 controls) -- <orientation input="quat">, the
first actuator with different input and output widths. The signature is
recorded in a new per-actuator field actuator_ctrlspec (mjtCtrlChart),
whose meaning is scoped by the gain type the way gain/bias parameters are;
ctrlnum is derived from it at compile time and remains the layout
authority. An explicit field rather than width inference or a prm slot:
width-as-chart cannot express same-width signatures (upcoming servo input
subsets), and prm slots are the input_mode pattern this stack retires.
The force law normalizes the commanded quaternion, making it scale- and
antipodally-invariant. The all-zero ctrl still maps to the identity via
mju_normalize4, but it is a degenerate point (a nudge of any component
commands a half-turn), so quat inputs reset to the identity quaternion:
new mj_resetCtrl sets neutral ctrl values (zero, except qw = 1), called
by mj_resetData and the viewers' Clear All. The quat chart is
restricted to dyntype 'none': integrating a quaternion setpoint linearly
is not meaningful on the manifold. New mjsActuator.ctrlspec field carries
the signature through the spec and XML round-trip.
Actuator sensors (actuatorpos/vel/frc) now report one value per force
output; dim = 3 on an SO3 actuator.
As the first actuator with nu != nactuator, this commit also makes the
viewers multi-input aware: the control sliders in simulate and studio,
which indexed per-actuator arrays by control index (out of bounds on
this model class), are generated per control and labeled with the
actuator name plus an input suffix ("orient/qw"), via the new
introspection helper mj_actuatorInputName -- the single source of truth
for input names, extended by each new multi-input type (quaternion
components are w-first: qw, qx, qy, qz). Slider ranges now honor a
defined ctrlrange even when ctrllimited is false: range is the UI hint,
limited is the clamp -- wrapped and expmap setpoints are unbounded but
still want finite sliders, while quat components are truly bounded.
The rotational demo model is orientation.xml under
test/engine/testdata/actuation/, upgraded to a three-way contrast:
per-axis wrapped servos vs an expmap-commanded vs a quat-commanded
orientation actuator, on identical checker-textured boxes. It is loaded
by the mixed-axis contrast and input-name tests, and doubles as the
viewer test model (slider groups of 3 independent, 3 grouped, 4 grouped).
PiperOrigin-RevId: 951607063
Change-Id: If235dba8e2f2ca72672e7c62531a27e967c6a373
The new function mjs_getOriginSpec returns the mjSpec that was used to define a given mjsElement. Unlike mjs_getSpec, this value remains constant even after the element has been attached to a different model.
PiperOrigin-RevId: 911930951
Change-Id: Ia9cd79d9dfabc513d6121eadcffc5d41075224c9
- Remove `lugre:viscous`, should now be added directly to actuator `damping`. Trying to do this for the user was incompatible with default inheritance (compounding instead of overriding).
- Move voltage limiting from the `saturation` to the `controller` attribute.
- Fix indexing issues in default inheritance.
PiperOrigin-RevId: 897087642
Change-Id: I5388c2633e15c7e223992e7eb5d6a28db75a6438
In a follow-up, mjs_detach will be changed to only remove without deleting an element.
PiperOrigin-RevId: 773637351
Change-Id: I9ee4d3584ba88ccc225591337cf036bab806e25c
Also add `SaveAndReadXML` function to test fixture using `mjSpec` as input.
PiperOrigin-RevId: 765393821
Change-Id: Ic257addd2fc89678fc11b226c168c077626cc51e
For the MJCF -> USD plugin, and I suspect other usecases for user values, it's necessary to give ownership of the object to Mujoco. However since they get type erased, we can't clean up the data automatically for the user. Instead this allows c++ clients to provide a cleanup function with their data.
PiperOrigin-RevId: 756832010
Change-Id: I80b8e7822e1a0e399a0d19dcaa57ee69b3ccc16a
Also raise error if the frame is not found in the mjCBody copy constructor.
Fixes#2543.
PiperOrigin-RevId: 742624013
Change-Id: I4999b3165c97f8d079412214d027ca7a8dae8cb3
This is required in preparation of changing the spec.attach behavior in the Python bindings.
PiperOrigin-RevId: 730810198
Change-Id: I095808f0afe62b5bbd27201ed5c75804e0e9c4bf
This can happen when a body is detached without compiling or recompiling.
Also added error catching when trying to delete a body instead of detaching it.
Fixes#2327
PiperOrigin-RevId: 712526730
Change-Id: I4b48df83120fca12d475c85b3a54893841449653
This enables to generate a list of all body children of a given type.
Also, add recursive option to mjs_firstChild and mjs_nextChild. Fixes#2112.
PiperOrigin-RevId: 681039348
Change-Id: Iebbb26fd5ec314150206edfdddd88633baa0bec6
This CL adds error handling to the mj_recompile function. If the recompile fails, the function will return -1 and set the error message in the spec. The Python wrapper for mj_recompile will catch the error and raise a ValueError exception.
PiperOrigin-RevId: 666784579
Change-Id: I225eca1769ea839c782be3c03fc4ff1ea5885a48
Yuval Tassa