Optical implementation of closed loop controllers for mechatronic systems

Abstract

The paper investigates the implementation of closed loop controllers of optomechatronic systems using optical components for signal transmission and control loop implementation. The system used for illustration is a DC position servomotor under state feedback control. The comparison is carried out between electric-electronic implementation and optical implementation for an environment with significant electromagnetic noise. For the optical implementation a photodiode is used for converting analog voltage output from position and velocity sensors into modulated 900 nm light, transmitted over a significant distance by a multi mode glass fiber (MMGF) to a controller implemented with a tunable optical amplifier. As an alternative, attenuators can also be used for controller implementation. The signal from controller is again transmitted 1550 nm MMGF to a photodetector that converts the signal into an analog voltage input to motor driver. Experimental results will illustrate the performance of the proposed optical implementation and advantages vs. electric-electronic implementation using a Lab View platform for data acquisition and display.