Inertial Measurement Unit (IMU)

A ~sensors.Imu models the two quantities produced by a conventional inertial measurement unit:

• sensors.ImuData.ang_vel_b: angular velocity [rad/s] relative to the world, expressed in the IMU frame.
• sensors.ImuData.lin_acc_b: proper linear acceleration [m/s²], expressed in the IMU frame.

Proper acceleration is what an accelerometer measures. It is zero in free fall and points upward with magnitude $g$ for a stationary sensor supported against gravity. This differs from the coordinate acceleration reported by the pva.

Configure the sensor

Attach the sensor to a rigid body or to a fixed child frame beneath one. offset places and orients the measurement frame relative to the parent frame.

from isaaclab.sensors import ImuCfg
base_imu = ImuCfg(
    prim_path="{ENV_REGEX_NS}/Robot/base/imu",
    update_period=0.0,
    offset=ImuCfg.OffsetCfg(
        pos=(0.0, 0.0, 0.05),
        rot=(0.0, 0.0, 0.0, 1.0),
    ),
    debug_vis=True,
)

Both data fields are ~isaaclab.utils.warp.ProxyArray buffers. For E environments, their Torch views have shape (E, 3):

imu_data = scene["base_imu"].data
angular_velocity = imu_data.ang_vel_b.torch
proper_acceleration = imu_data.lin_acc_b.torch

The acceleration estimate depends on consecutive simulation states. Reset the scene and its sensors together so derivative history is not carried across episodes. Use a sensor update period compatible with the control loop that consumes the measurement.

A complete runnable example is available as imu:

uv run --extra isaacsim isaaclab example imu