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twodaccelerationsensor

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twodaccelerationsensor

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Library

Iconic Diagrams\Mechanical\Translation\2DSmallAngles

Use

Domains: Continuous. Size: 1-D/2-D. Kind: Iconic Diagrams (1D Translation, 1D Rotation, 2D Planar).

Description

This model is used to find the absolute acceleration of a TwoDBody model. It has a port P which can be connected to the body and it has three output signals that denotes the x- and y-acceleration and the angular acceleration of the body.

 

The acceleration output is calculated out of the velocity by differentiation. 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.

 

The equations of this model are:

 

P.F = 0;

ax = 2*pi*f*( P.v[1] - int(ax, 0));

ay = 2*pi*f*( P.v[2] - int(ay, 0));

alpha = 2*pi*f*( P.v[3] - int(alpha, 0));

Interface

Ports

Description

P[3]

Port with three degrees of freedom (x, y, q).

Causality

 

fixed force out P

 

Outputs

 

ax

Absolute acceleration [m].

ay

Absolute acceleration [m].

alpha

Absolute acceleration [rad].

Initial Values

 

ax_initial

Initial acceleration [m]

ay_initial

Initial acceleration [m]

alpha_initial

Initial angular acceleration [m]