Studies on Opto-Pneumatic Servo System. 1st Report. Development of servo System in which Optical Control Signal is Fed Back Directly or Indirectly.

Abstract

Present electrical servo systems are sensitive to environmental hazards such as electromagnetic noise and radiation. To avoid such influences, it is effective to use laser beams and optical fibers. Our purpose is to develop an optical servo system in which an optical signal is used as a control signal in part or all of the system. In this paper, we describe the development of two types of optical servo system which consist of a photo-fluidic interface, two tested double-acting booster amplifiers, a pneumatic cylinder and an opto-optical encoder. One type is the cart position control system in which the optical signal is fed back directly, and the other type is that in which the optical signal is fed back indirectly. As the result of experiments on these systems, it is shown that the cart positioning in which an optical control signal is fed back directly can be realized by using dither generated in a booster amplifier. In the tested servo system in which an optical signal is fed back indirectly, the position control performance can be improved using a P-controller to compensate the friction, compared with the direct feedback type.