New generation of gimbals systems for laser positioning applications

Abstract

Omniwrist III is a new sensor mount developed under Air Force funding that emulates the kinematics of a human wrist. Driven by two linear motors and computer controlled, it is capable of a full 180° hemisphere of pitch/yaw motion. A comprehensive laboratory testing of one of few existing devices of this type, installed in the Laser Research Laboratory at Binghamton University, has resulted in the establishment of a complete transfer matrix-type model relating pitch/yaw coordinates of the sensor mount to the voltage signals applied to the motors. Although dynamic characteristics of the device are position-dependent, it has the potential for exceeding bandwidth and positioning accuracy of a traditional gimbals system at least by the factor of ten. The device is suitable for the application of the most advanced control strategies that will result in the further enhancement of its dynamic performance thus extending the scope of its application to various problems of satellite communications, LADAR, laser weapon systems, etc. This study is aimed at the investigation of the best performance characteristics (bandwidth, tracking error, cross-coupling effects, etc.) attainable under advanced control laws. The authors intend to consider implementation of such control laws as optimal control utilizing dynamic programming, gain scheduling, and fuzzy logic control. The results of this research will be incorporated in the future papers. It is shown that Omniwrist III with the appropriate controls could be considered as a new generation of gimbals system.