Research And Implementation Of Control System For Precision Active Vibration Isolation Platform

Environmental vibration and internal excitation are the key factors that affect the precision and performance of precision machining equipment and measuring instruments.Therefore,the precision active vibration isolation system which can isolate the foundation vibration and suppress the direct disturbance effectively becomes the necessary guarantee for precision manufacturing and measuring equipment.This thesis focuses on the vibration isolation bandwidth and vibration isolation performance requirements of the precision active vibration isolation system,and carries on the analysis and design of the control system for the precision active vibration isolation platform.The main work and achievements are as follows:The dynamic model of precision active vibration isolation platform is established.The mechanism of vibration isolation and active control of six degrees of freedom is expounded,the main vibration isolation performance of vibration isolation system is determined,and the design of control system is completed.For the broadband,high precision control requirements,the hardware design of the active vibration isolation control system is completed.According to the characteristics of the speed sensor and its low frequency expansion method,the conditioning circuit of the sensor is designed and realized.According to the structure and principle of Lorentz motor,the Lorentz motor driver is designed and realized.The selected main control unit is introduced in detail.Some second-order IIR digital filters for implementing the algorithm are designed to meet the requirement of simple and practical of the control algorithm for active vibration isolation system.The feedback controller is constructed in the form of cascaded second-order IIR filters,which can increase the gain of feedback control as much as possible on the premise of stability.In order to suppress the foundation vibration better,the foundation feedforward control is introduced,the theoretical model of feedforward control is deduced and the adaptive feedforward control algorithm is analyzed.According to the two methods,the feedforward controller is designed respectively.The experimental platform of the active vibration isolation system is set up.The uniaxial feedback control experiment and the feedforward control experiment of the vibration isolation platform are designed,and the vibration isolation performance of the vibration isolation system is tested.Experiments show that the vibration isolation bandwidth and vibration decay rate of the precision active vibration isolation system can meet the requirements.