Title :
Gain-phase margin analysis of dynamic fuzzy control systems
Author :
Perng, Jau-Woei ; Wu, Bing-Fei ; Chin, Hung-I ; Lee, Tsu-Tian
Author_Institution :
Dept. of Electr. & Control Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
Abstract :
In this paper, we apply some effective methods, including the gain-phase margin tester, describing function and parameter plane, to predict the limit cycles of dynamic fuzzy control systems with adjustable parameters. Both continuous-time and sampled-data fuzzy control systems are considered. In general, fuzzy control systems are nonlinear. By use of the classical method of describing functions, the dynamic fuzzy controller may be linearized first. According to the stability equations and parameter plane methods, the stability of the equivalent linearized system with adjustable parameters is then analyzed. In addition, a simple approach is also proposed to determine the gain margin and phase margin which limit cycles can occur for robustness. Two examples of continuous-time fuzzy control systems with and without nonlinearity are presented to demonstrate the design procedure. Finally, this approach is also extended to a sampled-data fuzzy control system.
Keywords :
continuous time systems; fuzzy control; fuzzy systems; limit cycles; nonlinear control systems; sampled data systems; stability; transfer functions; continuous-time fuzzy control system; describing function; dynamic fuzzy control system; equivalent linearized system; function plane; gain-phase margin analysis; limit cycle; parameter plane; sampled-data fuzzy control system; stability equation; Control system analysis; Control systems; Fuzzy control; Fuzzy systems; Limit-cycles; Nonlinear dynamical systems; Robustness; Stability analysis; Stability criteria; Transient analysis; Algorithms; Computer Simulation; Feedback; Fuzzy Logic; Models, Statistical; Nonlinear Dynamics; Systems Theory;
Journal_Title :
Systems, Man, and Cybernetics, Part B: Cybernetics, IEEE Transactions on
DOI :
10.1109/TSMCB.2004.831772