Research On Key Technologies Of Vibration Suppression For Precision Active Vibration Isolation System

Environmental vibration is the key factor affecting precision equipment manufacturing and measurement accuracy,and active vibration isolation is an important means of suppressing environmental vibration.In order to further improve the vibration suppression performance,the key technologies of vibration suppression for precision active vibration isolation system were studied from four aspects: dynamic modeling,vibration control method,parameter measurement methods and controller design.First of all,the dynamic model of the precision active vibration isolation system was established.The effects of symmetric and asymmetric distributions about the mass of payload on the kinetic equations were analyzed.Modal decoupling of dynamic equations was achieved by using modal theory.A hybrid control strategy based on modal decoupling control method for ground-based vibration feedforward control and payload vibration feedback control was proposed.Next,for the undetermined parameters in the dynamic equation of the vibration isolation system,the measurement methods of the center of gravity,mass and inertia of the payload were proposed.Therefore,the parameters of the mass matrix,the stiffness matrix and the damping matrix were determined.The simulation model of the precision active vibration isolation system based on Simulink was established,and the simulation experiments were carried out.The results showed that these measurement methods are effective.Then,the controller for the precision active vibration isolation system was designed,including position controller(position loop),model-based ground feedforward controller and payload vibration feedback controller(velocity loop).The control parameters tuning methods for the controller were proposed.Meanwhile,the control system software was developed based on the positioning requirements and vibration suppression requirements of the precision active vibration isolation system.Finally,the experimental platform of the precision active vibration isolation system was built.The positioning experiment and the six-degree-of-freedom vibration suppression experiment were carried out.It was shown that the position control accuracy meets the requirements of the precision equipment;the six-degree-of-freedom active vibration suppression can significantly reduce the vibration transmissibility of the vibration isolation system,so that the vibration level of the payload platform meets the environmental vibration requirements of precision equipment.