Rotational Motion Sensor (AB)

Motion sensor in angle-based rotational systems

Since R2026a

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  • Rotational Motion Sensor (AB) block

Libraries:
Simscape / Foundation Library / Rotational / Sensors

Description

The Rotational Motion Sensor (AB) block measures absolute or relative angle, velocity, and acceleration in an angle-based rotational network. The sensor does not apply any torque to the network. The sensor is ideal because it does not account for inertia, friction, delays, energy consumption, and so on.

B and F are angle-based rotational conserving ports.

ɑ, ω, and θ are physical signal output ports for acceleration, velocity, and angle, respectively. The visibility of these ports is controlled by block parameters. If you enable port ɑ, the block performs additional computations, to measure acceleration based on velocity. To avoid unnecessary model complexity, it is recommended that in each instance of the block you enable only the ports that you actually use for measurement.

To perform relative measurements, set the Measurement reference parameter to Difference and connect the sensor in parallel with the block, or several blocks, where you want to measure the angle, velocity, and acceleration.

Examples

Interpreting Angle in the Angle-Based Rotational Domain

Interpreting Angle in the Angle-Based Rotational Domain

Set up and interpret angles in angle-based rotational models. It provides background information to explain the underlying concepts. The angle-based rotational domain tracks angle, θ, and rotational velocity, ω, at every node. Use angle-based rotational blocks to model rotational systems where knowing multiple component angles is important.

Ports

Output

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Physical signal output port for acceleration.

Dependencies

To enable this port, select the Acceleration check box.

Physical signal output port for angular velocity.

Dependencies

To enable this port, select the Velocity check box.

Physical signal output port for angle.

Dependencies

To enable this port, select the Position check box.

Conserving

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Angle-based rotational conserving port that represents the base connection.

Angle-based rotational conserving port that represents the follower connection.

Dependencies

To enable this port, set the Measurement reference parameter to Difference.

Parameters

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Select whether to perform absolute or relative measurements:

  • Difference — Measure the acceleration, velocity, and angle of port F relative to port B.

  • Absolute — Disable port B and measure the acceleration, velocity, and angle of port F with respect to the world frame.

Selecting this check box exposes output port ɑ, which lets you measure acceleration. Exposing port ɑ also involves additional computations, to measure acceleration based on velocity, therefore this port is off by default.

Selecting this check box exposes output port ω, which lets you measure velocity.

Selecting this check box exposes output port θ, which lets you measure angle.

Selecting this check box exposes an additional parameter, Lower bound for angle wrapping, X, and keeps the measured rotational angle within the specified range, regardless of the number of revolutions performed by the object and the direction of rotation. When this check box is cleared, the output range is unrestricted.

The block keeps the measured rotational angle within the range from the wrap angle value, X, to 2π+X radians, that is, to 360+X degrees.

Dependencies

To enable this parameter, select the Enable angle wrapping to [X, 2π+X) check box.

Extended Capabilities

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C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2026a

See Also

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