Modern Control Engineering

(Chris Devlin) #1
678 Chapter 9 / Control Systems Analysis in State Space

EXAMPLE 9–11 Consider the system given by


For this case,

The system is therefore completely state controllable.

Alternative Form of the Condition for Complete State Controllability. Consider


the system defined by


(9–56)


where


If the eigenvectors of Aare distinct, then it is possible to find a transformation matrix


Psuch that


Note that if the eigenvalues of Aare distinct, then the eigenvectors of Aare distinct; how-


ever, the converse is not true. For example, an n*nreal symmetric matrix having


multiple eigenvalues has ndistinct eigenvectors. Note also that each column of the P


matrix is an eigenvector of Aassociated with


Let us define


(9–57)


Substituting Equation (9–57) into Equation (9–56), we obtain


(9–58)


By defining


P-^1 B=F=AfijB


z# =P-^1 APz+P-^1 Bu


x=Pz


li(i=1, 2,p,n).


P-^1 AP=D= F


l 1


0


l 2











0


ln


V


B=n*r matrix


A=n*n matrix


u=control vector (r-vector)


x=state vector (n-vector)


x



=Ax+Bu


CBABD= B


0

1

1

- 1

R =nonsingular


B


x# 1
x# 2

R= B


1

2

1

- 1

RB


x 1
x 2

R + B


0

1

R[u]


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