Rotational Spring

Ideal spring in mechanical rotational systems

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Libraries:
Simscape / Foundation Library / Mechanical / Rotational Elements

Description

The Rotational Spring block represents an ideal mechanical rotational linear spring, described with the following equations:

$$T=K·\phi$$

$$\phi ={\phi }_{init}+{\phi }_R-{\phi }_C$$

$$\omega =\frac{d\phi }{dt}$$

where

• T is torque transmitted through the spring.

• K is spring rate.

• φ is relative displacement angle, that is, spring deformation.

• φ_init is spring preliminary winding.

• φ_R and φ_C are absolute angular displacements of ports R and C, respectively.

• ω is relative angular velocity.

• t is time.

The block positive direction is from port R to port C. This means that if the port R velocity is greater than that of port C, the block transmits torque from R to C.

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.

Examples

Simple Mechanical System

A model of a system that connects rotational and translational motion. A summing lever drives a load consisting of a mass, viscous friction, and a spring connected to its joint C. Joint B is suspended on two rotational springs connected to reference point through a wheel and axle and a gear box. Joint A is connected to a torque source through a gear box and a wheel and axle mechanism.

• Open Model

Mechanical Rotational System with Stick-Slip Motion

A mechanical rotational system with stick-slip friction. An inertia is connected to a fixed point by spring and damper. The inertia is driven by a velocity source via a stick-slip friction element. The friction element has a difference between the breakaway and the Coulomb frictions, resulting in stick-slip motion of the inertia.

• Open Model

Ports

Conserving

R — Rod

mechanical rotational

Mechanical rotational conserving port associated with the rod, that is, the moving body.

C — Case

mechanical rotational

Mechanical rotational conserving port associated with the case, that is, the stationary body.

Parameters

Spring rate — Spring rate

10 N*m/rad (default) | scalar

Spring rate.

Extended Capabilities

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

Version History

Introduced in R2007a