ss2zp {control}

State-space representation to zero-pole-gain representation

Description

ss2zp converts a system represented in state-space form to zero-pole-gain model

Usage

ss2zp(a,b,c,d,iu)

Arguments

a

An n x n matrix

b

An n x m matrix

c

An p x n matrix

d

An p x m matrix

iu

A numeric value denoting number of inputs. default value is 1.For example, if the system has three inputs (u1, u2, u3), then iu must be either 1, 2, or 3, where 1 implies u1, 2 implies u2, and 3 implies u3.

Details

ss2zp converts a system represented in zero-pole form to state-space by converting from zero-pole to transfer function and from transfer functon to state-space The vector P contains the pole locations of the denominator of the transfer function.

Other possible usages for ss2zp are:

ss2zp(a,b,c,d)

ss2zp(sys)

ss2zp(sys, iu)

where sys is an object of state-space class

Value

Returns a list object of 'zpk' class, consisting of z, p and k. The numerator zeros are returned in the columns of matrix Z with number of columns equal to number of outputs. The gains for each numerator transfer function are returned in column vector K. P, a column vector contains the pole locations of the denominator of the transfer function.

See Also

zp2ss ss2tf

Examples

A <- rbind(c(-2, -1), c(1,0)); B <- rbind(1,0);
C <- cbind(0,1); D <- 0;
sys2 <- ss(A,B,C,D)
ss2zp(sys2$A,sys2$B,sys2$C,sys2$D)
ss2zp( zp2ss ( tf2zp( c(1,1,1), c(1,2,1) ) ) )

## Not run:   A MIMO system 
A = rbind(c(0,1), c(-25,-4)); B = rbind(c(1,1), c(0,1));
C = rbind(c(1,0), c(0,1)); D = rbind(c(0,0), c(0,0))
ss2tf(A,B,C,D,1) # to obtain output for input 1
ss2tf(A,B,C,D,2) # to obtain output for input 2

## Not run:   OR 

systems <- vector("list", ncol(D))
for(i in 1:ncol(D)){ systems[[i]] <- ss2zp(A,B,C,D,i) }
systems
systems[[1]]
systems[[2]]