Premium
Loop‐shaping based H ∞ robust control of a horizontal shaft magnetic bearing
Author(s) -
Matsumura Fumio,
Hatake Kazuhiro,
Fujita Masayuki
Publication year - 1994
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.4391140111
Subject(s) - magnetic bearing , control theory (sociology) , transfer function , converters , robustness (evolution) , closed loop transfer function , open loop controller , control system , controller (irrigation) , bearing (navigation) , engineering , control engineering , digital control , robust control , full state feedback , computer science , closed loop , control (management) , magnet , electronic engineering , mechanical engineering , agronomy , biochemistry , chemistry , electrical engineering , voltage , artificial intelligence , biology , gene
This paper considers H ∞ control design of a magnetic bearing from the viewpoint of loop shaping. Feedback control is indispensable for a magnetic bearing, since it is essentially an unstable system. For feedback control, a mathematical model is required. However, it does not always express the exact behavior of the system, hence the model has various uncertainties such as the errors of parameters, neglected nonlinearities, or unmodeled dynamics. The controller is needed to guarantee robustness for both stability and performance against these uncertainties on the model. First, based on some assumptions, a linear state space model of a magnetic bearing is shown. Second, the experimental machine and the surroundings of its controller are introduced. The experimental machine is a 4‐axis controlled horizontal shaft magnetic bearing. The controller consists of a digital signal processor with fast A/D converters and D/A converters. Third, the control system is designed using normalized coprime factor plant descriptions. Selecting shaping functions in this procedure called “The Loop‐Shaping Design Procedure (LSDP),” shape the open‐loop transfer function and the transfer functions of the closed‐loop system can be shaped. Finally, several experiments are carried out according to the aforementioned designed controller.