MULTI-PHASE ANGULAR DISPLACEMENT MEASUREMENT TECHNIQUE

THE STATE OF THE ART IN PRECISE AND ACCURATE MEASUREMENT OF ANGULAR DISPLACEMENT REPRESENT THE CULMINATION OF NEARLY A HALF CENTURY OF REFINEMENT AND EVOLUTION OF WELL KNOWN OPTICAL AND ELECTRICAL TECHNIQUES. CONSEQUENTLY FURTHER IMPROVEMENTS IN A PARTICULAR PERFORMANCE AREA GENERALLY INVOLVE SUBSTANTIAL TRADEOFFS IN OTHER EQUALLY CIRITICAL AREAS. IN PARTICULAR, PRESENT TECHNOLOGY DOES NOT DEAL EFFECTIVELY WITH THE TRADEOFF BETWEEN ACCURACY AND ANGLUAR SPEED OR SLEW RATE. SUBMICRORADIAN ANGLUAR MEASUREMENTS AT RATES IN EXCESS OF 100 TIMES PER SECOND IS THE EXPECTED PERFORMANCE OF AN OPTRA PROPOSED SYSTEM. THE TECHNICAL BASIS FOR THIS SYSTEM REPRESENTS A SIGNIFICANT DEPARTURE FROM ESTABLISHED METHODOLOGY FOR READING THE POSITION OF AN ENCODER SCALE. A LASER DIODE LIGHT SOURCE, AN INNOVATIVE OPTICAL SCHEME FOR GENERATING A VIRTUAL READOUT GRATING, AND A RECENTLY DEVELOPED MULTI-PHASE DETECTION AND PROCESSING TECHNIQUE WHEN COMBINED WITH ESTABLISHED RADIAL GRATING GENERATION TECHNOLOGIES FORM THE BASIS FOR A SYSTEM WHICH HAS NO PRACTICAL LIMIT TO THE TRADEOFF BETWEEN SPEED AND ACCURACY OR PRECISION. ADDITIONAL BENEFITS INCLUDE SIGNIFICANT REDUCTIONS IN SIZE, WEIGHT AND COST OVER PRESENTLY AVAILABLE SYSTEMS.