Modern Control Engineering

(Chris Devlin) #1

Section 10–6 / Design of Regulator Systems with Observers 783


The error equation for the minimum-order observer is


(10–111)


By combining Equations (10–110) and (10–111), we get


with the initial condition


MATLAB Program 10–15 produces the response to the given initial condition. The


response curves are shown in Figure 10–21.They seem to be acceptable.


B


x( 0 )


e( 0 )


R = E


1


0


0


1


0


U


B


x



e


#R = B


A-BK


0


BKb


Abb-Ke Aab


RB


x


e


R


e



=AAbb-Ke AabBe


MATLAB Program 10–15


% Response to initial condition.


A = [0 1 0;0 0 1;0 -24 -10];


B = [0;10;-80];


K = [1.25 1.25 0.19375];


Kb = [1.25 0.19375];


Ke = [-1;6.25];


Aab = [1 0]; Abb = [0 1;-24 -10];


AA = [A-BK BKb; zeros(2,3) Abb-Ke*Aab];


sys = ss(AA,eye(5),eye(5),eye(5));


t = 0:0.01:8;


x = initial(sys,[1;0;0;1;0],t);


x1 = [1 0 0 0 0]*x';


x2 = [0 1 0 0 0]*x';


x3 = [0 0 1 0 0]*x';


e1 = [0 0 0 1 0]*x';


e2 = [0 0 0 0 1]*x';


subplot(3,2,1); plot(t,x1); grid


xlabel ('t (sec)'); ylabel('x1')


subplot(3,2,2); plot(t,x2); grid


xlabel ('t (sec)'); ylabel('x2')


subplot(3,2,3); plot(t,x3); grid


xlabel ('t (sec)'); ylabel('x3')


subplot(3,2,4); plot(t,e1); grid


xlabel('t (sec)'); ylabel('e1')


subplot(3,2,5); plot(t,e2); grid


xlabel('t (sec)'); ylabel('e2')

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