Lyapunov-function-based design of fuzzy logic controllers and its application on combining controllers

L. K. Wong, Hung Fat Frank Leung, Peter K.S. Tarn

Research output: Journal article publicationJournal articleAcademic researchpeer-review

74 Citations (Scopus)


This paper presents the design of fuzzy logic controllers (FLC's) for nonlinear systems with guaranteed closedloop stability and its application on combining controllers. The design is based on heuristic fuzzy rules. Although each rule in the FLC refers to a stable closed-loop subsystem, the overall system stability cannot be guaranteed when all these rules are applied together. In this paper, it is proved that if each subsystem is stable in the sense of Lyapunov (ISL) under a common Lyapunov function, the overall system is also stable ISL. Since no fuzzy plant model is involved, the number of subsystems generated is relatively small, and the common Lyapunov function can be found more easily. To probe further, an application of this design approach to an inverted pendulum system that combines a sliding-mode controller (SMC) and a state feedback controller (SFC) is to be reported. Each rule in this FLC has an SMC or an SFC in the consequent part. The role of the FLC is to schedule the final control under different antecedents. The stability of the whole system is guaranteed by the proposed design approach. More importantly, the controller thus designed can keep the advantages and remove the disadvantages of the two conventional controllers.
Original languageEnglish
Pages (from-to)502-509
Number of pages8
JournalIEEE Transactions on Industrial Electronics
Issue number3
Publication statusPublished - 1 Dec 1998


  • Combining controllers
  • Fuzzy logic control
  • Lyapunov
  • Stability

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


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