Study on Feed Forward and Feedback Hybrid Control for High-Tech Platform

Abstract

This paper first design a multi -degree -of -freedom high -tech platform which used air springs as passive vibration isolation elements and giant magnetostrictive actuators as active vibration isolation elements. For this hig h-tech platform, a compound controller with feed forward and feedback compensators is designed. For making up the property of time lag of feedback control, the control system take feed forward control as the primary controller, while feedback control as th e compensator. Among the vibrational disturbance of the high -tech platform received, the disturbance of ground motion and instruments and equipments on the platform can be measured, which we regard as the input and adopt fuzzy control as feed forward contr ol; at the same time measure the dynamical response of the platform, adopt neural network control as feedback control. We take the sum of the output of feed forward controller and feedback controller as the total output U. Fuzzy feed forward control can no t only make up the disfigurement of badly real -time property of neural network control, but also avoid the question of accessional disturbance that commonly feed forward control may bring. The results show that the developed compound controller has good is olation performance and better real -time property if the controller is properly desi gned.