ADVANCED ACTUATORS FOR THE CONTROL OF LARGE SPACE STRUCTURES

NEW SPACECRAFT DESIGNS FEATURE LARGE STRUCTURES CHARACTERIZED BY LOW NATURAL FREQUENCIES, LIGHTLY DAMPED STRUCTURAL MODES, AND STRINGENT POINTING AND VIBRATION PERFORMANCE REQUIREMENTS. THESE LARGE SPACE STRUCTURES (LSS) POSE UNIQUE AND DIFFICULT CONTROL PROBLEMS. AN IMPORTANT PART OF THE SOLUTIONS TO THESE CONTROL PROBLEMS ISTHE DEVELOPMENT OF ACTUATORS THAT ALLOW THE APPLICATION OF FORCE AND OR TORQUE TO THE SPACE STRUCTURE. THIS PROPOSED RESEARCH PROGRAM WILL EXAMINE ADVANCED SIX-DEGREE-OF-FREEDOM ACTUATORS EMPLOYING MAGNETIC SUSPENSIONS. THESE ACTUATORS WILL CONSIST OF A MAGNETICALLY SUSPENDED REACTION MASS THAT HAS THREE-DEGREES-OF-FREEDOM IN BOTH TRANSLATION AND ROTATION. THESE ACTUATORS WILL EMPLOY A UNIQUE LARGE-ANGLE-MAGNETIC SUSPENSION THAT ALLOWS GIMBALLING OF THE SUSPENDED REACTION MASS. THESE ADVANCED ACTUATORS ARE EXPECTED TO HAVE A NUMBER OF ADVANTAGES OVER CONVENTIONAL ACTUATORS INCLUDING LOW NOISE, HIGH BANDWIDTH, AND RELAXED CONSTRAINTS ON ACTUATOR PLACEMENT. THE PROPOSED RESEARCH PROGRAM WILL DEVELOP THESE ACTUATORS AND ASSES THEIR PERFORMANCE COMPARED TO CONVENTIONAL ACTUATORS.