www.gusucode.com > control 案例程序 matlab源码代码 > control/RelativeInputAndOutputPassivityIndicesExample.m

    %% Relative, Input, and Output Passivity Indices
% Compute passivity indices for the following dynamic
% system:
%
% $$ G(s) = \frac{s^2 + s + 5s + 0.1}{s^3 + 2s^2+ 3s + 4} $$
%
%%
G = tf([1,1,5,.1],[1,2,3,4]);
%%
% Compute the relative passivity index.
R = getPassiveIndex(G)
%%
% The system is passive, but with a relatively small excess of passivity.
%%
% Compute the input and output passivity indices.
nu = getPassiveIndex(G,'input')
rho = getPassiveIndex(G,'output')
%%
% This system is both input strictly passive and output strictly passive.
%%
% Compute the combined I/O passivity index.
tau = getPassiveIndex(G,'io')
%%
% The system is very strictly passive as well.  A system that is very
% strictly passive is also strictly positive real.  Examining the Nyquist
% plot confirms this, showing that the frequency response lies entirely
% within the right half-plane. 
nyquistplot(G)
%% 
% The relatively small |tau| value is reflected in how close the frequency
% response comes to the imaginary axis.