Fuzzy inputs

Deals with fuzzy signals at the input of a fuzzy controller. Commonly, almost all theoretical considerations and practical applications of fuzzy control deal with crisp signals fed to the input of the controller. In order to take into account side-effects arising with the use of sensory information, such as noise or spatial distribution of a signal, it is of interest to show how the control loop behaves in the presence of fuzzy signals. In this paper, some useful operations on fuzzy sets are first described, especially time-varying membership functions and their derivatives. On this basis, sliding mode control and a related fuzzy control strategy are applied to fuzzy signals. In this context, stability and robustness are discussed. Simulation results compare the method of using inputs with the fuzzy input approach