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<?xml version="1.0" encoding="ISO-8859-1" standalone="no"?>
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<!DOCTYPE MAN SYSTEM "../../manrev.dtd">
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<LANGUAGE>eng</LANGUAGE>
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<TYPE>Scilab Function</TYPE>
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<DATE>April 1993</DATE>
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<SHORT_DESCRIPTION name="lin"> linearization</SHORT_DESCRIPTION>
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<CALLING_SEQUENCE_ITEM>[A,B,C,D]=lin(sim,x0,u0) </CALLING_SEQUENCE_ITEM>
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<CALLING_SEQUENCE_ITEM>[sl]=lin(sim,x0,u0) </CALLING_SEQUENCE_ITEM>
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<PARAM_NAME>sim</PARAM_NAME>
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<PARAM_NAME>x0, u0</PARAM_NAME>
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<SP>: vectors of compatible dimensions</SP>
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<PARAM_NAME>A,B,C,D</PARAM_NAME>
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<SP>: real matrices</SP>
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<PARAM_NAME>sl</PARAM_NAME>
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<SP>: <VERB>syslin</VERB> list</SP>
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linearization of the non-linear system <VERB>[y,xdot]=sim(x,u)</VERB>
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around <VERB>x0,u0</VERB>.</P>
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<P><VERB>sim</VERB> is a function which computes <VERB>y</VERB> and <VERB>xdot</VERB>.</P>
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The output is a linear system (<VERB>syslin</VERB> list) <VERB>sl</VERB> or the
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four matrices <VERB>(A,B,C,D)</VERB></P>
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For example, if <VERB>ftz</VERB> is the function passed to ode e.g.</P>
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and if we assume that <VERB>y=x</VERB></P>
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<P><VERB>[z]=ode(x0,t0,tf,list(ftz,u)</VERB> compute <VERB>x(tf)</VERB>.</P>
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If <VERB>simula</VERB> is the following function:</P>
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deff('[y,xd]=simula(x,u)','xd=ftz(tf,x,u); y=x;');
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the tangent linear system <VERB>sl</VERB> can be obtained by:</P>
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[A,B,C,D]=lin(simula,z,u)
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sl = syslin('c',A,B,C,D,x0)
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deff('[y,xdot]=sim(x,u)','xdot=[u*sin(x);-u*x^2];y=xdot(1)+xdot(2)')