20-sim webhelp > Library > Bond Graph > 2d > I-2


I-2

Navigation:  Library > Bond Graph > 2d >

I-2

Previous pageReturn to chapter overviewNext page

Library

Bond Graph

Use

Domains: Continuous. Size: 2-D. Kind: Block Diagrams, Bond Graphs.

Description

This model is the multiport equivalent of the single I storage element. Consequently the constitutive equation must be written as a matrix-vector multiplication. The element has a preferred flow out causality. The corresponding constitutive equations then contain an integration. The element can also have the non-preferred effort out causality. The constitutive equations then contain a derivation, which can only be simulated when the Backward Differentiation Formula integration algorithm is available:

 

flow out causality (preferred):

 

state = int(p.e) + state(0);

p.f = inverse(I)*state;

output = state;

 

effort out causality:

 

state = I*p.f;

p.e = d state / dt;

output = state;

Interface

Ports

Description

p[2]

Input port of the storage element (columnvector with size 2).

Causality

 

preferred effort out

A flow out causality results in a derivative constitutive equation.

Outputs

 

output[2]

The output signal is equal to the state (columnvector with size 2).

Parameters

 

I[2,2]

The storage element constants (matrix of size [2,2]).

Initial Values

 

state(0)[2]

The initial values of the storage element (columnvector with size 2).

Limitations

The preferred equation contains an inverted I matrix. The elements of this matrix should be chosen with care to prevent this matrix from becoming singular.