Relative Angle Actuator (AB)

R2026b

Ideal actuator that maintains relative angle between ports proportional to the input signal

Since R2026a

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Relative Angle Actuator (AB) block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Simscape / Foundation Library / Rotational / Sources

Description

The Relative Angle Actuator (AB) block represents an ideal actuator that maintains a specified relative angle between its ports regardless of the load at the connected ports.

B and F are angle-based rotational conserving ports. The physical signal at port S specifies the angle between the ports B and F. A positive signal at port S indicates that port F has a more positive angle than port B.

The block logs these variables:

• t — torque that port B applies to port F to maintain the specified relative angular velocity.

• theta_rel — relative angle between the actuator ports, specified by the signal at port S, $${\theta }_{\text{Rel}}={\theta }_{\text{F}}-{\theta }_{\text{B}}$$, where θ_B and θ_F are the angles of ports B and F, respectively.

For more information, see Data Logging.

Examples

Interpreting Torque in the Angle-Based Rotational Domain

Describes how to interpret torques in a Simscape™ angle-based rotational network. It outlines the key concepts for understanding the signs of logged torques. It examines rotational spring systems driven by torque sources at different ends, as well as a rotational system of inertias, to illustrate the torque behavior.

• Open Live Script

Ports

Input

S — Control signal that specifies relative angle between the ports, rad

physical signal

Physical signal input port for the control signal that drives the actuator. A positive signal at this port indicates that port F has a more positive angle than port B.

Programmatic Use

Port: S

Conserving

B — Base port

angle-based rotational

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

Programmatic Use

Port: B

F — Follower port

angle-based rotational

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

Programmatic Use

Port: F

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"fl_lib/Rotational/Sources/Relative Angle Actuator (AB)"

Example: add_block("fl_lib/Rotational/Sources/Relative Angle Actuator (AB)","myModel/myBlock",MakeNameUnique="on")

For information about programmatic access to individual block parameters, see the Programmatic Use section of parameter descriptions on this page.

Extended Capabilities

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

Version History

Introduced in R2026a