Modern Control Engineering

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

(9–4)


The controllable canonical form is important in discussing the pole-placement approach


to control systems design.


Observable Canonical Form. The following state-space representation is called


an observable canonical form:


(9–5)


(9–6)


Note that the n*nstate matrix of the state equation given by Equation (9–5) is the


transpose of that of the state equation defined by Equation (9–3).


Diagonal Canonical Form. Consider the transfer-function system defined by Equa-


tion (9–2). Here we consider the case where the denominator polynomial involves only


distinct roots. For the distinct-roots case, Equation (9–2) can be written as


(9–7)


The diagonal canonical form of the state-space representation of this system is given by


=b 0 +


c 1


s+p 1


+


c 2


s+p 2


+p+


cn


s+pn


Y(s)


U(s)


=


b 0 sn+b 1 sn-^1 +p+bn- 1 s+bn


As+p 1 BAs+p 2 B p As+pnB


y =[0 0 p 0 1]G


x 1


x 2











xn- 1


xn


W +b 0 u


F


x



1

x


# 2    x



n

V = F


0 1    0


0 0    0


p


p


p


0 0    1


- an


- an- 1











- a 1


VF


x 1


x 2











xn


V + F


bn-an b 0


bn- 1 - an- 1 b 0











b 1 - a 1 b 0


Vu


y= Cbn-an b 0 bn- 1 - an- 1 b 0 pb 1 - a 1 b 0 DF


x 1


x 2











xn


V +b 0 u


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