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Slider-Crank

Generic slider-crank mechanism

  • Library:
  • Simscape / Foundation Library / Mechanical / Mechanisms

  • Slider-Crank block

Description

The Slider-Crank block represents the slider-crank mechanism as a converter between the continuous rotational motion of the crank and the oscillating translational motion of the slider.

The mechanism has two connections:

  • Port C corresponds to the crank and is a mechanical rotational conserving port.

  • Port S corresponds to the slider and is a mechanical translational conserving port.

The Crank radius and Rod length parameters describe the mechanism geometry. The Crank inertia parameter helps move the mechanism through the positions at the top and bottom when the rod is exactly aligned with the center of the crank.

The purpose of the Slider stiffness and Slider damping parameters is to reduce inertia coupling between the ports, which can cause computational issues. The block applies the stiffness and damping between the ideal position of the slider (as calculated by the geometry) and the actual position of the translational conserving port, S. This compliance avoids a direct nonlinear coupling between the ports. Higher stiffness causes the motion to be closer to ideal, but increases the system stiffness. The damping helps smooth the ringing that can be caused by the stiffness.

Variables

You can set initialization targets for the crank angle and velocity at the start of simulation, using both positive and negative values.

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

Ports

Conserving

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Mechanical rotational conserving port associated with the crank.

Mechanical translational conserving port associated with the slider.

Parameters

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The radius of the crank. The parameter value must be greater than zero.

Length of the rod connecting the crank and the slider. The parameter value must be greater than Crank radius.

The inertia of the crank, which helps move the mechanism through the positions at the top and bottom when the rod is exactly aligned with the center of the crank. The parameter value must be greater than zero.

Together with Slider damping, introduces a compliance that helps reduce inertia coupling between the ports. Higher stiffness causes the motion to be closer to ideal, but increases the system stiffness. The parameter value must be greater than zero.

Together with Slider stiffness, introduces a compliance that helps reduce inertia coupling between the ports. Higher damping values smooth the ringing that can be caused by the stiffness. The parameter value must be greater than zero.

Extended Capabilities

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

Introduced in R2019a