Linear periodic control for strong /spl rho/-stabilization with infinite gain margin

Author(s):  
S. Galeani ◽  
O.M. Grasselli ◽  
L. Menini
2000 ◽  
Vol 33 (14) ◽  
pp. 323-328
Author(s):  
Sergio Galeani ◽  
Osvaldo Maria Grasselli ◽  
Laura Menini

Author(s):  
Jatin K Pradhan ◽  
Arun Ghosh

It is well known that linear time-invariant controllers fail to provide desired robustness margins (e.g. gain margin, phase margin) for plants with non-minimum phase zeros. Attempts have been made in literature to alleviate this problem using high-frequency periodic controllers. But because of high frequency in nature, real-time implementation of these controllers is very challenging. In fact, no practical applications of such controllers for multivariable plants have been reported in literature till date. This article considers a laboratory-based, two-input–two-output, quadruple-tank process with a non-minimum phase zero for real-time implementation of the above periodic controller. To design the controller, first, a minimal pre-compensator is used to decouple the plant in open loop. Then the resulting single-input–single-output units are compensated using periodic controllers. It is shown through simulations and real-time experiments that owing to arbitrary loop-zero placement capability of periodic controllers, the above decoupled periodic control scheme provides much improved robustness against multi-channel output gain variations as compared to its linear time-invariant counterpart. It is also shown that in spite of this improved robustness, the nominal performances such as tracking and disturbance attenuation remain almost the same. A comparison with [Formula: see text]-linear time-invariant controllers is also carried out to show superiority of the proposed scheme.


1992 ◽  
Vol 19 (5) ◽  
pp. 379-390 ◽  
Author(s):  
Graham C. Goodwin ◽  
Arie Feuer

Sign in / Sign up

Export Citation Format

Share Document