Translational Inerter (PB)

R2026b

Two-port inertia in position-based translational systems

Since R2026b

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Translational Inerter (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 Inerter (PB) block represents an ideal translational inerter in position-based translational systems. Force is proportional to the rate of change of the relative velocity of the ports.

Use this block in high-performance suspension systems, to decouple weave and roll modes, or in applications where you need to model a passively tuned mass-spring-damper response.

The block uses the equations

$$f=-I\cdot {\dot{v}}_{rel}$$

$$v_{rel}=v_F-v_B$$

$$length=x_F-x_B$$

where:

• f is the force transmitted through the inerter.

• I is the inertance.

• v_rel is the relative velocity.

• v_B and v_F are the absolute velocities of ports B and F, respectively.

• length is the inerter length.

• x_B and x_F are the absolute positions of ports B and F, respectively.

Connections B and F are position-based translational conserving ports. The inerter force acts from port B on port F. Positive inerter force drives port F in the positive direction. When length is positive, port F has a more positive position than port B. For more information, see Two-Port Block Orientation and Force Flow Conventions.

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.

Ports

Conserving

B — Base port

position-based translational

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

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.

Parameters

Inertance — Proportionality coefficient

1 kg (default) | scalar

Proportionality coefficient between the force and the rate of change of the relative velocity across the ports.

Extended Capabilities

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

Version History

Introduced in R2026b