20-sim webhelp > Library > Iconic Diagrams > Mechanical > Rotation > Actuators > positionactuator


positionactuator

Navigation:  Library > Iconic Diagrams > Mechanical > Rotation > Actuators >

positionactuator

Previous pageReturn to chapter overviewNext page

Library

Iconic Diagrams\Mechanical\Rotation\Actuators

Use

Domains: Continuous. Size: 1-D. Kind: Iconic Diagrams (Rotation), Block Diagrams.

Description

This model represents an ideal actuator. An angle input signal is differentiated by a state variable filter to an angular velocity at the rotation port. The actuator is mounted to the fixed world:

 

p.omega = dphi/dt;

p.T = indifferent;

 

Differentiation is performed by a state variable filter:

DifferentiateSVF

The S-domain function of this filter is equal to:

DifferentiateSVFequation

where f is the cut-off frequency. For very high values of f, the output becomes the pure derivative of the input. High values of f, however, increase simulations times. A good trade-off is a starting value of 1e5.

Interface

Ports

Description

p

Rotation port.

Causality

 

fixed angular velocity out

 

Input

 

phi

Angle [rad].

Parameters

 

f

omega_initial

Cut-off frequency of the differentiation [Hz].

Initial angular velocity at the port [m/s].