Improvement of controller design for positive polynomial fuzzy systems based on symbolic analysis and optimization of reduced-Order parameters of interval type-2 membership functions
Ziyu Wang , Meng Han , Yiming Han , Ge Guo , Zhengsong Wang
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引用次数: 0
Abstract
In this paper, the controller design of positive interval Type-2 polynomial fuzzy-model-based (PIT2PFMB) systems is investigated, where the PIT2PFMB open-loop system and the controller are permitted to employ distinct premise membership functions. While this premise mismatch enhances controller design flexibility, it introduces conservatism when analyzing stability via Lyapunov stability theory. To mitigate this conservatism, an advanced membership function dependent analysis method is proposed: type-reduction parameters are modeled as system symbolic variables, with their information, together with other information of membership functions, incorporated into the stability conditions. This approach expands the stability regions of the systems. During the type-reduction implementation of the interval Type-2 (IT2) fuzzy controller, the gradient descent approach is employed to optimize the embedded type-1 membership functions of the controllers, thereby improving the control performance. Simulation results will demonstrate the effectiveness of the proposed methodology in expanding the stability region and improving control performance.
期刊介绍:
Since its launching in 1978, the journal Fuzzy Sets and Systems has been devoted to the international advancement of the theory and application of fuzzy sets and systems. The theory of fuzzy sets now encompasses a well organized corpus of basic notions including (and not restricted to) aggregation operations, a generalized theory of relations, specific measures of information content, a calculus of fuzzy numbers. Fuzzy sets are also the cornerstone of a non-additive uncertainty theory, namely possibility theory, and of a versatile tool for both linguistic and numerical modeling: fuzzy rule-based systems. Numerous works now combine fuzzy concepts with other scientific disciplines as well as modern technologies.
In mathematics fuzzy sets have triggered new research topics in connection with category theory, topology, algebra, analysis. Fuzzy sets are also part of a recent trend in the study of generalized measures and integrals, and are combined with statistical methods. Furthermore, fuzzy sets have strong logical underpinnings in the tradition of many-valued logics.