Study on Optical Servo System (Estimation of Dynamic Characteristics of Bimorph-Type Optical Actuator using PLZT Elements).

Abstract

A step response relating displacement to light intensity in a bimorph-type optical actuator consisting of two sheets of PLZT elements is analyzed theoretically, and the experimental equations on the principal parameters included in the theoretical equation of the step response are derived from the fundamental experiment on the PLZT elements with various sizes. Comparing the analytical result with the experimental result of the step response of an optical actuator manufactured as a trial, the results show linear and first-order lag factor characteristics and agree well with each other with regard to the final value of the displacement. The time constant in the analysis shows a value 0.44 times as great as that in the experiment. The cause for this difference is discussed in detail. If this cause is taken into consideration, the dynamic characteristics of a bimorph-type optical actuator may be estimated exactly by the analytical result shown in this paper.