Research On The Active Isolation System Controlled By Aerostatic And Voice Coil Motor

With the gradual development of space technology, microelectronics and precision and ultra-precision machining and measurement disciplines, the requirement of products accuracy is getting higher and higher, the requirements for the anti-vibration and dynamic stability of the instrument are also increasing. The large ultra-precision manufacturing equipment, high precision measurement equipment, and the large precision experimental equipment are all built on the base of the vibration isolation base. And, the vibration isolation platform has a good vibration isolation effect. So the air flotation isolation technology is a key issue of the current research. The traditional passive vibration isolation can only rely on the platform of vibration isolation effect to suppress the noise, for some precision experiments which require the platform vibration velocity smaller and the inherent frequency lower, traditional passive vibration isolation cannot meet the requirements. Therefore, this paper introduces active vibration isolation tec hnology. In this paper, a kind of active control method is designed, which uses the voice coil motor as the active actuator to realize the low vibration speed and natural frequency of the vibration isolation system. The main research contents are as follow s,First, according to the functional requirements of the vibration isolation system, designed the mechanical structure of corresponding active vibration isolation unit, and according to the physical factors of the designed aerostatic structure, gas chamber pressure, volume, and bearing area etc., the stiffness and damping coefficients of the system are derived, and then the physical model is established. The six degree of freedom kinematic model is established and the influence of the voice coil motor on the position sensor of the vibration isolation platform is obtained.Secondly, establish the model of active vibration isolation system, design and analysis control strategy of the aerostatic preliminary positioning, precise positioning and active control, then study and research the control method of isolation of the active control emphatically. At last, the PID control method which has good control effect is used to control the vibration isolation.Again, according to the composite control method, a low frequency and high gain linear amplifier is designed, using the data acquisition module to collect the vibration signal, calculate the output signal according to the control program driving the voice coil motor to inhibit vibration signal.Finally, the experimental analysis of the active vibration isolation platform is carried out. The paper test the frequency response of the vibration signal conditioning circuit, which has excellent frequency response characteristics between the input and output signals. The vibration isolation effect and the accuracy of the vibration isolation system when using the active vibration isolation technology are tested. The vibration velocity reached 15.2 μm/s when controlled by the active vibration isolation technology, which is 42.6% lower than the traditional passive control. The effective value of vibration acceleration(RMS) is reduced from 476μm/s2 to 228μm/s2, which is reduced by 52.1% compared with the passive control. The natural frequency reached 1.625 Hz, 40.9% lower than the passive control. The positioning accuracy reached ±4μm, which was increased by 33.3% compared with passive control.