A HYBRID ANALYTICAL/INTELLIGENT APPROACH TO FAULT-TOLERANT CONTROL OF LARGE SPACE STRUCTURES

THIS PROJECT COMBINES HYBRID CONTROL-THEORETIC TECHNIQUES AND ARTIFICIAL INTELLIGENCE (AL) FOR THE DESIGN OF FAULT-TOLERANT CONTROL STRATEGIES FOR LARGE SPACE STRUCTURES. AVAILABLE AL-BASED OR PURELY CONTROL-THEORETIC TECHNIQUES FOR FAULT-TOLERANT CONTROL OFFER NO UNIFIED METHODOLOGY TO INTEGRATE THE DIVERSE ISSUES OF SYSTEM MODELING, FAULT DETECTION AND ISOLATION, FAULT PROPAGATION, SYSTEM RESTRUCTURING, AND CONTROLLER RECONFIGURATION. THIS PROJECT CAPITALIZES ON STRUCTURAL FEATURES OF THE SYSTEM. THE FAULT-TOLERANT DESIGN PROCEDURE COMBINES SIGNAL REDUNDANCY AND FUZZY LOGIC. WHEN A FAULT IS DETECTED, CAUSAL OR QUALITATIVE REASONING IS USED TO MODEL ITS PROPAGATION TO ADJACENT SUBSYSTEMS. THE SYSTEM IS THEN RESTRUCTURED BY ISOLATING FAULTY COMPONENTS. FINALLY, A STRUCTURAL CONTROL LAW THAT RECONFIGURES THE ORIGINAL SYSTEM CONTROLLER TO MEET THE PRIMARY OBJECTIVE OF GUARANTEED STABILITY WHILE THE SYSTEM IS OPERATING IN A DEGRADED MODE. ALGORITHMIC DEVELOPMENTS WILL BE DEMONSTRATED, USING THE THERMAL CONTROL SYSTEM OF THE SPACE STATION'S COMMON MODULE AS THE TEST BED. THIS PROJECT COMBINES HYBRID CONTROL-THEORETIC TECHNIQUES AND ARTIFICIAL INTELLIGENCE (AL) FOR THE DESIGN OF FAULT-TOLERANT CONTROL STRATEGIES FOR LARGE SPACE STRUCTURES. AVAILABLE AL-BASED OR PURELY CONTROL-THEORETIC TECHNIQUES FOR FAULT-TOLERANT CONTROL OFFER NO UNIFIED METHODOLOGY TO INTEGRATE THE DIVERSE ISSUES OF SYSTEM MODELING, FAULT DETECTION AND ISOLATION, FAULT PROPAGATION, SYSTEM RESTRUCTURING, AND CONTROLLER RECONFIGURATION. THIS PROJECT CAPITALIZES ON STRUCTURAL FEATURES OF THE SYSTEM. THE FAULT-TOLERANT DESIGN PROCEDURE COMBINES SIGNAL REDUNDANCY AND FUZZY LOGIC. WHEN A FAULT IS DETECTED, CAUSAL OR QUALITATIVE REASONING IS USED TO MODEL ITS PROPAGATION TO ADJACENT SUBSYSTEMS. THE SYSTEM IS THEN RESTRUCTURED BY ISOLATING FAULTY COMPONENTS. FINALLY, A STRUCTURAL CONTROL LAW THAT RECONFIGURES THE ORIGINAL SYSTEM CONTROLLER TO MEET THE PRIMARY OBJECTIVE OF GUARANTEED STABILITY WHILE THE SYSTEM IS OPERATING IN A DEGRADED MODE. ALGORITHMIC DEVELOPMENTS WILL BE DEMONSTRATED, USING THE THERMAL CONTROL SYSTEM OF THE SPACE STATION'S COMMON MODULE AS THE TEST BED.