Backlash

Navigation:  Library > Iconic Diagrams > Mechanical > Translation > Components >

Backlash

Previous pageReturn to chapter overviewNext page

Library

Iconic Diagrams\Mechanical\Translation\Components

Use

Domains: Continuous. Size: 1-D. Kind: Iconic Diagrams (Translation).

Description

This model represents backlash by a spring damper system. Inside an outside the play, spring and damping can be set separately. Discontinuities are avoided by adding a round off. The model can has a force out causality. The port p of this model has separate high and low terminals. The equations are:

 

p.F = p_high.F = p_low.F

p.v = p_high.v - p_low.v

Backlash

with x the position within the play. Real backlash behavior is obtained by choosing low stiffness and damping values inside the play and choosing high stiffness and damping values outside the play.

 

The parameter ep determines the smoothness of the force curve that is obtained. A larger value (> 0.01) makes the force change gradually when the position reaches the play boundaries. A smaller value (< 0.001 ) makes the force change abruptly. This is shown in the figure below. A good starting value for ep is 1e-4.

Backlash1

Interface

Ports

Description

p_high, p_low

Both terminals of port p (Translation).

Causality

 

fixed force out

 

Parameters

 

s

c1

c2

d1

d2

ep

Interval of the play [m]

Stiffness in the play [N/m]

Stiffness outside the play [N/m]

Damping inside the play [Ns/m]

Damping outside the play [Ns/m]

Relative round off (1e-6 -> sharp edges, 1e-2 -> smoother)

Initial Values

 

x_initial

Initial position in the play [m], -s/2 < x_initial < s/2