FUZZY CONTROL-SYSTEMS STABILITY - TIME AND FREQUENCY-DOMAIN CRITERIA

Stability is the most important attribute of any system. A prerequisit e for all stability criteria of control systems is the existence of a mathematical model. In contrast, fuzzy control systems are often desig ned based on heuristic human knowledge and without a mathematical mode l, hence, it has been a difficult task to determine stability of fuzzy control systems under such restrictions. This paper uses the Takagi/S ugeno type of Fuzzy rules whose consequences are analytical, and singl etons are used as a basis for a number of sufficiency conditions for s tability. The schemes considered here are time-domain, but a brief sur vey which proceeds the main results considers frequency domain as well . Both Lyapunov and interval matrix criteria are presented with some p roofs and numerical examples.