www.gusucode.com > robust 案例源码程序 matlab代码 > robust/GridOpenLoopAndClosedLoopResponsesOfUncertainSystemExample.m
%% Grid Open-Loop and Closed-Loop Responses of Uncertain System %% % Create two uncertain real parameters |gamma| and |tau|. % The nominal value of |gamma| is 4 and its range is % 3 to 5. The nominal value of |tau| is 0.5 and its % value can vary by +/- 30 percent. % Copyright 2015 The MathWorks, Inc. gamma = ureal('gamma',4); tau = ureal('tau',.5,'Percentage',30); %% % These uncertain parameters are used to construct an uncertain transfer function |p|. % An integral controller, |c|, is synthesized for the % plant |p| based on the nominal values of |gamma| and |tau|. % The uncertain closed-loop system |clp| is formed. p = tf(gamma,[tau 1]); KI = 1/(2*tau.Nominal*gamma.Nominal); c = tf(KI,[1 0]); clp = feedback(p*c,1); %% % The figure below shows the open-loop unit step response (top plot) and % closed-loop response (bottom plot) for a grid of 20 values of % |gamma| and |tau|. subplot(2,1,1); step(gridureal(p,20),6) title('Open-loop plant step responses') subplot(2,1,2); step(gridureal(clp,20),6) %% % The plot illustrates the low-frequency closed-loop insensitivity % achieved by the PI control system.