Add SO3 transmission and native orientation actuator.
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
This commit is contained in:
Yuval Tassa
committed by
Copybara-Service
Copybara-Service
parent
a8545ac7cc
commit
072e963fa0
@@ -1115,6 +1115,7 @@ typedef struct mjModel_ {
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int* actuator_biastype; // bias type (mjtBias) (nactuator x 1)
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int* actuator_ctrladr; // address of first control (nactuator x 1)
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int* actuator_ctrlnum; // number of controls (nactuator x 1)
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int* actuator_ctrlspec; // input signature, scoped by gaintype (nactuator x 1)
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int* actuator_outadr; // address of first force output (nactuator x 1)
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int* actuator_outnum; // number of force outputs, from trntype (nactuator x 1)
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int* actuator_actadr; // first activation address; -1: stateless (nactuator x 1)
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@@ -1136,11 +1137,11 @@ typedef struct mjModel_ {
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int* actuator_group; // group for visibility (nactuator x 1)
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mjtNum* actuator_user; // user data (nactuator x nuser_actuator)
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int* actuator_plugin; // plugin instance id; -1: not a plugin (nactuator x 1)
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mjtBool* actuator_forcelimited;// is force limited (nactuator x 1)
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mjtNum* actuator_forcerange; // range of forces (nactuator x 2)
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mjtBool* actuator_ctrllimited; // is control limited (nu x 1)
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mjtNum* actuator_ctrlrange; // range of controls (nu x 2)
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mjtNum* actuator_gear; // scale length and transmitted force (nout x 6)
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mjtBool* actuator_forcelimited;// is force limited (nout x 1)
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mjtNum* actuator_forcerange; // range of forces (nout x 2)
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mjtNum* actuator_acc0; // acceleration from unit force in qpos0 (nout x 1)
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mjtNum* actuator_length0; // actuator length in qpos0 (nout x 1)
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mjtNum* actuator_lengthrange; // feasible actuator length range (nout x 2)
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@@ -2241,6 +2242,7 @@ typedef struct mjsActuator_ { // actuator specification
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mjtDyn dyntype; // dynamics type
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double dynprm[mjNDYN]; // dynamics parameters
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int actdim; // number of activation variables
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int ctrlspec; // input signature, scoped by gaintype; 0: type default
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mjtBool actearly; // apply next activations to qfrc
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// transmission
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@@ -2499,6 +2501,7 @@ typedef enum mjtTrn { // type of actuator transmission
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mjTRN_TENDON, // force on tendon
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mjTRN_SITE, // force on site
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mjTRN_BODY, // adhesion force on a body's geoms
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mjTRN_SO3, // torque on a relative orientation (3 force outputs)
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mjTRN_UNDEFINED = 1000 // undefined transmission type
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} mjtTrn;
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@@ -2516,6 +2519,7 @@ typedef enum mjtGain { // type of actuator gain
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mjGAIN_AFFINE, // const + kp*length + kv*velocity
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mjGAIN_MUSCLE, // muscle FLV curve computed by mju_muscleGain()
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mjGAIN_DCMOTOR, // DC motor gain: K or K/R
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mjGAIN_SO3, // geodesic servo on an SO3 transmission: force = kp * log(error)
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mjGAIN_USER // user-defined gain type
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} mjtGain;
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typedef enum mjtBias { // type of actuator bias
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@@ -2523,8 +2527,13 @@ typedef enum mjtBias { // type of actuator bias
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mjBIAS_AFFINE, // const + kp*length + kv*velocity
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mjBIAS_MUSCLE, // muscle passive force computed by mju_muscleBias()
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mjBIAS_DCMOTOR, // DC motor bias: back-EMF, cogging, LuGre friction
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mjBIAS_SO3, // damping term of the SO3 geodesic servo
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mjBIAS_USER // user-defined bias type
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} mjtBias;
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typedef enum mjtCtrlChart { // so3 input signature (actuator_ctrlspec): orientation chart
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mjCHART_EXPMAP = 1, // exponential-map orientation target: 3 controls
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mjCHART_QUAT = 2 // quaternion orientation target: 4 controls
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} mjtCtrlChart;
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typedef enum mjtObj { // type of MujoCo object
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mjOBJ_UNKNOWN = 0, // unknown object type
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mjOBJ_BODY, // body
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@@ -3500,6 +3509,7 @@ mjtSize mj_sizeModel(const mjModel* m);
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mjData* mj_makeData(const mjModel* m);
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mjData* mj_copyData(mjData* dest, const mjModel* m, const mjData* src);
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mjData* mjv_copyData(mjData* dest, const mjModel* m, const mjData* src);
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void mj_resetCtrl(const mjModel* m, mjData* d);
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void mj_resetData(const mjModel* m, mjData* d);
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void mj_resetDataDebug(const mjModel* m, mjData* d, unsigned char debug_value);
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void mj_resetDataKeyframe(const mjModel* m, mjData* d, int key);
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@@ -3611,6 +3621,7 @@ void mj_jacDot(const mjModel* m, const mjData* d, mjtNum* jacp, mjtNum* jacr,
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void mj_angmomMat(const mjModel* m, mjData* d, mjtNum* mat, int body);
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int mj_name2id(const mjModel* m, int type, const char* name);
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const char* mj_id2name(const mjModel* m, int type, int id);
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const char* mj_actuatorInputName(const mjModel* m, int id, int input);
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void mj_fullM(const mjModel* m, const mjData* d, mjtNum* dst);
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void mj_mulM(const mjModel* m, const mjData* d, mjtNum* res, const mjtNum* vec);
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void mj_mulM2(const mjModel* m, const mjData* d, mjtNum* res, const mjtNum* vec);
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@@ -3970,6 +3981,8 @@ const char* mjs_setToPosition(mjsActuator* actuator, double kp, double kv[1],
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const char* mjs_setToIntVelocity(mjsActuator* actuator, double kp, double kv[1],
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double dampratio[1], double timeconst[1], double inheritrange);
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const char* mjs_setToVelocity(mjsActuator* actuator, double kv);
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const char* mjs_setToOrientation(mjsActuator* actuator, double kp, double kv[1],
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double dampratio[1], int ctrlspec);
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const char* mjs_setToDamper(mjsActuator* actuator, double kv);
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const char* mjs_setToCylinder(mjsActuator* actuator, double timeconst,
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double bias, double area, double diameter);
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