The dcmotor input block is any subset of the canonical list [pos, vel,
ff, voltage], selected with input="pos vel ff voltage" and recorded as
mjtCtrlInput bits in actuator_ctrlspec like pid. Tokens are required in
canonical order: the attribute denotes a set, the block always packs
canonically, and accepting permutations invites reading the string as a
layout choice. The mode flag in gainprm[8] is retired (reserved,
written 0).
Controller gains are now in torque space, as for pid: the controller
commands tau = kp*(q*-l) + kd*(v*-ldot) + ki*x_I + tau_ff over the
present inputs (absent setpoints frozen at zero) and converts to drive
voltage V = R/K * tau + K*ldot. The second term compensates back-EMF,
as the current loop of a real torque-mode driver does (torque commands
are current commands): commanded torque is delivered exactly until a
limit binds, and the torque-speed envelope emerges from the Vmax clamp.
The map uses the nameplate R: thermal resistance growth is not
compensated, so a hot motor under-delivers by R/R(T). A stateless
setpoint dcmotor now matches <pid> exactly, for any K and R; the old
back-EMF droop remains available as the physical behavior of the raw
voltage path. Voltage-space datasheet gains convert by K/R. Controller
inputs require a positive motor constant (the map divides by K), and
controller gains require a controller input.
ff and voltage are distinct inputs, different in kind: ff is a torque
feedforward added to the controller output, uniform with pid's ff
(feedforward in the actuator's output space), while voltage is the raw
terminal voltage of the physical device, injected downstream of the
controller and its Vmax clamp, unclamped (ctrlrange bounds it if
desired). input="voltage" is the default: the plain voltage-commanded
motor, whose behavior is unchanged by this commit. The integrator
always accumulates position error; the old velocity mode's integral
term, ki*(int(u)dt - theta), which tracked the integral of the velocity
command, is retired without replacement, keeping ki mode-independent --
commanded integrated velocity belongs to an integrator activation
state, not to controller gains. slewmax rate-limits the first controller
input -- position setpoint (rad/s), velocity setpoint (rad/s^2) or torque
feedforward (N*m/s), each a real driver feature (reference ramping,
ramped-velocity and ramped-torque input modes); the raw voltage input
is never rate-limited and slewmax requires a controller input.
input="none" selects the empty signature: the actuator owns no controls
at all (nu = 0 is now legal with actuators present) and is purely
passive -- LuGre friction, cogging and back-EMF braking as passive
joint forces. This exists because auxiliary dynamic states (the LuGre
bristle) attach to actuators, not joints. The terminal voltage is
identically zero, i.e. a shorted motor (dynamic braking); motorconst=0
decouples the electrical branch. mjINPUT_NONE is a distinct enum value
because ctrlspec = 0 means "unset, use the type default". History and
delay require an input; the controller voltage override and input read
in mj_fwdActuation are gated on a nonempty block.
The analytic velocity derivative of the controller becomes
dV/dw = -kd*R/K + K, whose second term cancels the back-EMF bias
exactly: the net damping of an unclipped torque-mode motor is -kd, and
of a voltage-mode or passive motor -K^2/R. Viewers label inputs via
mj_actuatorInputName: pos, vel, ff, voltage.
The dcmotor LaTeX design doc is updated accordingly: torque-space
units, the tau->V map and its saturation-generated envelope, the
input-block pipeline figure, and a Passive Operation section.
PiperOrigin-RevId: 965795351
Change-Id: Ibc308ca21bd6bad014e77f950ee08feaad449b73
<pid kp kv|dampratio [ki imax] [slewmax]> is a PID controller with real position and velocity setpoint inputs on a single force output, plus an optional feedforward input. With a zero velocity setpoint it reproduces <position> bit-exactly; the input signature is any subset of [pos, vel, ff], selected with input="..." and recorded as mjtCtrlInput bits in
actuator_ctrlspec; absent setpoint inputs are fixed at zero, so the control vector contains no inert entries.
kp and kv are single-sourced in the affine bias parameters (biasprm[1,2]) with no gainprm mirror: every consumer of the position-servo shape
(dampratio conversion, inheritrange, qDeriv) reads one location, which is what makes the bit-exact <position> parity possible. Controller state uses dyntype 'pid' with slot-gated activations in the order [slew, integral], following the dcmotor slot idiom: slewmax (dynprm[1]) rate limits the effective position setpoint through an activation holding it;
ki (gainprm[0]) integrates the position error -- wrapped on rotational transmissions -- with anti-windup clamping of the integrand at imax (dynprm[0]). Both features require the pos input. Servo input unpacking is shared with the dcmotor controller (unpackServoInputs); per-input ranges are exposed as posrange/velrange/ffrange.
This subsumes the functionality of the mujoco.pid plugin with proper activation state: correct under all integrators, visible to keyframes, act sensors and reset. Migration: kp/ki/kd map to kp/ki/kv, plugin imax is in force units (divide by ki), slewmax carries over; the single ctrl becomes input="pos".
PiperOrigin-RevId: 957588898
Change-Id: Id2786836ca6e76f58e5b5cc8323fc23be0a53784
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
Introduce a new header `gil.h` defining `MutexLockIfGilDisabled` to support thread-safety in both standard and free-threaded CPython builds.
Protect critical shared states and registries:
- Guard global Python callback pointers in `callbacks.cc` using a mutex. Move `gil_scoped_acquire` into local blocks around refcount modifications to prevent `longjmp` from bypassing destructors.
- Protect raw pointer maps in `structs_wrappers.cc` with static mutexes.
- Replace TOCTOU race in `mjcb_time` initialization with thread-safe `std::call_once`.
- Add synchronization to lazy indexer array cache initialization in `indexers.cc` and `indexer_xmacro.h`.
- Protect vector mutations in `StructListBase::PopulateUpTo` in `structs.h` with a mutex.
- Revert unnecessary atomic changes to threadpool counters.
- Declare free-threading compatibility by passing `pybind11::mod_gil_not_used()` to all extension modules.
Fixes#3259Fixes#3256Fixes#2978
PiperOrigin-RevId: 941101502
Change-Id: Iec4ce58afcbc75d4b0be6a9a21fc8a47854242e3
Correct argument types for timeconst and range parameters in pybind11
python bindings from C arrays to std::array.
Fixes#3282, #3282, #3318
Thanks to @Abzaek for original PRs
PiperOrigin-RevId: 932423401
Change-Id: Ic30ba076913693f5c0e545789690e8b0fa444390
For example, `compile mujoco_menagerie/robotis_op3/scene.xml` now outputs
```
Compile 1 (cold cache):
total: 317.2 ms
assets: 284.8 ms (wall clock)
load: 616.1 ms
hull: 26.4 ms
poly: 137.8 ms
inert: 177.8 ms
bvh: 568.2 ms
octr: 1.6 ms
tex: 25.3 ms
other: 32.4 ms
Compile 2 (warm cache):
total: 79.9 ms
assets: 54.5 ms (wall clock)
load: 888.5 ms
hull: 0.0 ms
poly: 0.0 ms
inert: 0.0 ms
bvh: 0.0 ms
octr: 0.0 ms
tex: 21.4 ms
other: 25.3 ms
```
PiperOrigin-RevId: 917850214
Change-Id: Iaec86230bec0faf2e47820e20cbff61de5b2621e
This change introduces MjVFS, an explicit object to mirror the C mjVFS. This is meant to replace the MjSpec.assets dict. This latter while convenient guides users towards harmful authoring patterns with respect to data duplication and spec attachment workflows. Making VFS management explicit should encourage better memory usage and allow us to make better compile time optimizations.
From this change, `spec.assets` is deprecated. However we will temporarily support backwards compatibility due to the wide spread usage. An error will be thrown if calling code tries to use a spec that uses both the assets dict and the new MjVfs.
PiperOrigin-RevId: 908772050
Change-Id: I77c6d0369307fc300c954768fed17401261e18da
This change disallows calling `mjs_delete` on an mjSpec that has been attached to another mjSpec via `mjs_attach`. Attempting to delete an element from an attached spec will now result in an error. The Python bindings for `mjSpec.delete` have been updated to raise a ValueError when this occurs.
PiperOrigin-RevId: 897266695
Change-Id: Ic0670125a3028191ec50eca890f02b5910ec8b03
- 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
- plugin system similar to mjpResourceProvider, but instead of loading a resource it converts an existing mjResource into an mjSpec.
- The returned spec is then composed into the referencing spec.
- This enables different file types to generate arbitrary specs, and allows us to separate format parsing from compilation code.
Follow up CLs will move some of the logic in src/engine for PNG, USD, KTX, OBJ loading into decoders.
The mj_parse function MjSpec from a given file, it's a more generic version of mj_parseXML.
In it's implementation, mj_parse as opposed to mj_parseXML will look for any registered decoder and
not assume we are striclty dealing with MJCF.
PiperOrigin-RevId: 826149497
Change-Id: I0ece26904280cb94bd5ded6dd5a565c539d60254
The user can recover the old behavior by passing prefix="".
This enables to attach children with default and save a valid result to XML.
PiperOrigin-RevId: 825011185
Change-Id: Id20c2589da928bf92b77bdb01cfba73dfc1d2f52
For backwards compatibility in the Python bindings, both `spec.compiler.meshdir` and `spec.meshdir` are now allowed.
Fixes#2834.
PiperOrigin-RevId: 809060113
Change-Id: Ie23f1c5dd57de43568312a8e062906f4013bb474
In a follow-up, mjs_detach will be changed to only remove without deleting an element.
PiperOrigin-RevId: 773637351
Change-Id: I9ee4d3584ba88ccc225591337cf036bab806e25c
This should enable other pybind modules to accept arguments of type MjSpec.
PiperOrigin-RevId: 745580987
Change-Id: I435a8d264149369e3fbee14c5d2c628ef74b2541
Yuval Tassa