User`s guide

Table Of Contents

9 Design Case Studies

9-36

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

ans =

'x-gap'

'x-force'

The second output 'x-force' is the rolling force measurement. The LQG

regulator will usethismeasurement todrivethe hydraulic actuatorand reduce

disturbance-induced thickness vari ations .

The LQG design involves two steps:

1 Design a full-state-feedback gain that minimizes an LQ performance

measure of the form

2 Design a Kalman filter that estimates the state vector given the force

measurements

'x-force'.

The performance criterion penalizes low and high frequencies equally.

Because low-frequency variations are of primary concern, eliminate the

() qδ







∞

∫

()