Translational Spacer (PB)

R2026b

Fixed length between blocks during simulation

Since R2024b

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Translational Spacer (PB) 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 / Translational / Elements

Description

The Translational Spacer (PB) block maintains a fixed length between ports B and F during simulation:

$$length=x_F-x_B$$

$$v_B=v_F$$

Connections B and F are position-based translational conserving ports. Length is positive when port F has a more positive position than port B. The spacer force acts from port B on port F. Positive spacer force drives port F in the positive direction. When length is positive, positive spacer force corresponds to the spacer in a state of compression.

The block has no parameters. You specify length as an initial variable target.

Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see Modify Nominal Values for a Block Variable.

To specify length:

• For a known length, specify it as a high-priority target.

• For an unknown fixed length, specify any value and set the priority to low or none. Then the solver computes a value for the length during model initialization.

Examples

Force Flow in the Position-Based Translational Domain

Describes how to interpret forces in a Simscape™ mechanical position-based translational network. The example summarizes rules for interpreting the signs of logged forces and then considers forces in three types of systems: springs being pulled or pushed from different ends, simple systems with external forces applied at a mid-point, and a more complex system with an external force applied at the mid-point.

• Open Live Script

Ports

Conserving

B — Base port

position-based translational

Position-based translational conserving port that represents the base connection.

Programmatic Use

Port: B

F — Follower port

position-based translational

Position-based translational conserving port that represents the follower connection. For positive length, port F has a more positive position than port B.

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/Translational/Elements/Translational Spacer (PB)"

Example: add_block("fl_lib/Translational/Elements/Translational Spacer (PB)","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 R2024b