Threshold fuzzy systems: a priority-based hierarchical control scheme

Introduces a trainable control methodology called threshold fuzzy systems (TFS). The need for TFS methods comes from controlling plants that exhibit a varying priority hierarchy. A trademark of these variable priority systems is that if a lower priority system task is completed before a higher priority one the system could become unstable. Designing a control structure that will take into account the varying priorities of a system is difficult. TFS control is shown to be a good approach to these types of systems. Key to the proposed TFS structure is the inclusion of a behaviorist fuzzy rulebase (BFR) and a rule dominance mechanism (RDM) into the classical fuzzy control architecture. The purpose and uses of the BFR and RDM are explained. The TFS control scheme is presented and symbolic and numerical examples are presented.