Specifications

LQG Regulation: Rolling Mill Example
10-35
% Input thickness/hardness disturbance model
Fix = tf(1e4,[1 0.05],'inputn','w-ix')
% Rolling eccentricity model
Fex = tf([3e4 0],[1 0.125 6^2],'inputn','w-ex')
% Gain from force to thickness gap
gx = 1e-6;
Next build the open-loop model shown in Figure 10-1 above. You could use the
function
connect for this purpose, but it is easier to build this model by
elementary
append and series connections.
% I/O map from inputs to forces f1 and f2
Px = append([ss(Hx) Fex],Fix)
% Add static gain from f1,f2 to outputs ”x-gap” and ”x-force”
Px = [-gx gx;1 1] * Px
% Give names to the outputs:
set(Px,'outputn',{'x-gap' 'x-force'})
Note: To obtain minimal state-space realizations, always convert transfer
function models to state space before connecting them. Combining transfer
functions and then converting to state space may produce nonminimal
state-space models.
The variable
Px now contains an open-loop state-space model complete with
input and output names.
Px.inputname
ans =
'u-x'
'w-ex'
'w-ix'
Px.outputname