MAGNETICALLY SUPPORTED ULTRAPRECISION BEARING DEVELOPMENT

THIS PROPOSAL PROPOSES AN APPROACH TO DESCRIBE & DEMONSTRATE MAGNETICALLY SUPPORTED ULTRAPRECISION BEARING FOR SEEKER AND SCANNER APPLICATIONS. THE MAGNETIC SUPPORT DESIGN APPROACH IS BASED ON A NOVEL HOMOPOLAR MAGNETIC CIRCUIT IMPLEMENTED BY MEANS OF A COMBINATION OF PERMANENT BIAS FIELDS AND ACTIVE CONTROL FIELDS. THE CONCEPT INCLUDES A CONTROL SYSTEM WHICH INCORPORATES ERROR SIGNALS FROM THE MAGNETIC BEARING POSITION SENSORS AS WELL AS FROM EXTERNAL SOURCES (E.G.,INERTIAL SENSORS). THE MAGNETIC SUPPORT IS DESIGNED TO REDUCE SCANNER TORQUE NOISE, AXIAL AND RADIAL RUNOUTS, AND ALSO TO PROVIDE HIGH BEARING STIFFNESS FOR PLATFORM MANEUVERS. THE DESIGN APPROACH MINIMIZES THE MAGNETIC SUPPORT SIZE, WEIGHT AND POWER COMPARED TO OTHER APPROACHES. THE BEARING DESIGN PROVIDES FULL FIVE-AXIS SUPPORT AND CONTROL AND NO OTHER BEARINGS ARE REQUIRED. THE PROJECT PROVIDES A HARDWARE DEMONSTRATION AND TEST DATA. THE MAGNETIC SUPPORT SPECIFICATIONS ARE: AXIAL AND RADIAL STIFFNESS GREATER THAN 5 X 105 POUNDS/INCH; AXIAL AND RADIAL RUNOUT LESS THAN 3 X 10-6 IN; POWER CONSUMPTION LESS THAN 10 WATTS. THEDESIGN APPROACH IS SCALABLE TO LARGER AND SMALLER SCANNERS THAN THE ONE DEMONSTRATED. THE DESIGN HAS PROVISIONS FOR ADDING AN INTEGRAL PRECISION SHAFT ANGLE ENCODER AND TORQUE MOTOR.