newton.sensors.SensorIMU#

class newton.sensors.SensorIMU(model, sites, *, verbose=None, request_state_attributes=True)[source]#

Bases: object

Inertial Measurement Unit sensor.

Measures linear acceleration (specific force) and angular velocity at the given sites. Each site defines an IMU frame; outputs are expressed in that frame.

This sensor requires the extended state attribute body_qdd. By default, constructing the sensor requests body_qdd from the model so that subsequent model.state() calls allocate it automatically. The solver must also support computing body_qdd (e.g. SolverMuJoCo).

The sites parameter accepts label patterns – see Label Matching.

Example

import warp as wp
import newton
from newton.sensors import SensorIMU

builder = newton.ModelBuilder()
builder.add_ground_plane()
body = builder.add_body(xform=wp.transform((0, 0, 1), wp.quat_identity()))
builder.add_shape_sphere(body, radius=0.1)
builder.add_site(body, label="imu_0")
model = builder.finalize()

imu = SensorIMU(model, sites="imu_*")
solver = newton.solvers.SolverMuJoCo(model)
state = model.state()

# after solver step
solver.step(state, state, None, None, dt=1.0 / 60.0)
imu.update(state)
acc = imu.accelerometer.numpy()
gyro = imu.gyroscope.numpy()
__init__(model, sites, *, verbose=None, request_state_attributes=True)#

Initialize SensorIMU.

Transparently requests the extended state attribute body_qdd from the model, which is required for acceleration data.

Parameters:

  • model (Model) – The model to use.

  • sites (str | list[str] | list[int]) – List of site indices, single pattern to match against site labels, or list of patterns where any one matches.

  • verbose (bool | None) – If True, print details. If None, uses wp.config.verbose.

  • request_state_attributes (bool) – If True (default), transparently request the extended state attribute body_qdd from the model. If False, model is not modified and the attribute must be requested elsewhere before calling model.state().

Raises:

ValueError – If no labels match or invalid sites are passed.

update(state)#

Update the IMU sensor.

Parameters:

state (State) – The state to update the sensor from.

accelerometer: array(ndim=1, dtype=vec3f)#

Linear acceleration readings [m/s²] in sensor frame, shape (n_sensors,).

gyroscope: array(ndim=1, dtype=vec3f)#

Angular velocity readings [rad/s] in sensor frame, shape (n_sensors,).