Dither-motor design with concurrent sensing and actuating piezoelectric materials (Ring laser gyroscope)

Abstract

The authors present an analytical model to predict the model parameters of a dither-motor structure in a ring laser gyroscope in which the piezoelectric sensor and actuator are employed as driving mechanisms to avoid the problem of so-called lock-in effects. It is shown that the natural frequency of a dither motor is strongly influenced by: (1) the inertia and stiffness of piezoelectric elements and bonding layers, (2) the location of piezoelectric elements, and (3) the interaction between structural vibration and piezoelectric actuation. Conventionally. piezoelectric elements are used for sensor and actuator independently. A technique for utilizing each of the piezoelectric elements concurrently for dither rate sensing and dither motion actuation is also developed. Experimental results show that the system performance and reliability can be significantly increased by accurately predicting the fundamental structural frequency and by implementing the concurrent sensing/actuating technique.