Active Control Algorithms for a Modified Hard-Mounted Isolation System

Abstract

It is well known that the trend of current high-tech equipment and processes development is ultra-precision and high-speed. Thus, vibration becomes a significant issue for those high-tech equipment and processes. When the environmental vibration exceeds the requirements of the precision equipment, vibration control techniques should be employed to improve the accuracy and resolution of that equipment. There are two types of vibration control techniques. One is passive isolation system; the other is active isolation system. Passive isolation system can provide better performance for higher frequencies. Active isolation system is used to improve the isolation performance for lower frequencies. However, passive isolation system has bad performance around the natural frequency. In addition, it cannot eliminate the effects of onboard disturbances on the equipment. Therefore, active isolation system becomes the major technology in the applications of vibration control for precision equipment. In this paper, a modified hard-mounted isolation system is proposed to improve the performance of hard-mounted systems. In this system, a voice coil motor is placed in parallel with the passive element and used to eliminate the effects of onboard disturbances on the equipment. A piezoactuator is still utilized to isolate the environmental vibration from the equipment. Furthermore, an active control algorithm is developed to achieve the optimal performance of low vibration transmissibility and high stiffness. The results are verified by the numerical simulations.