Design Of Active Vibration Isolation System Based On Electromagnetic And Floatation Hybrid Support

As a basis for a multi-disciplinary technical support, isolation has become the indispensable key technology in the field of sophisticated technology. With the development of the times, the current field of human cutting-edge technology has been developed to a breathtaking height compared to their predecessors. Such as LSI manufacturing, Laser Interferometer Gravitational-wave measurements, ultraprecision manufacturing, three-dimensional laser direct writing technology and other areas, have been met nano, sub-nanometer even more microscopic fields. However, any device on the ground is inseparable from the interference of earth vibration, so that isolation become the basis for the implementation and development of the above-mentioned areas of technology. For further development of the above-mentioned areas, effectively improving of vibration isolation technology has become the key technology.In the paper, the design of isolation system which based on flotation and magnetic bearing technology is introduced. A six degree-of-freedom(DOF) vibration isolation platform is composed of three-stage air bearing, which can be completely separated from the ground. The isolator can compensate for gravity of the load. It has a characteristic of high load-bearing, low-rigidity. On this basis, this paper designs an active vibration isolation scheme by voice coil actuator to improve the location accuracy and the isolation performance.This paper introduces the design of the machine structure firstly. The isolator uses air bearing as support. At the stage of technical design, it calculates the rigidity and damping parameters of the system according to the specified dimensions of the structure and working conditions. And then, a simulation of the model that mentioned above is carried out by ANSYS software. The principle of voice coil motor is analyzed. The processing and layout of the isolation system based on the voice coil motor is built.Secondly, mechanical structure with the adjustable stiffness in both horizontal and vertical directions is designed. In vertical direction, the magnetically suspended spring with the negative stiffness is introduced. The theory analysis and computer simulation of structural properties in the magnetically suspended spring is introduced. Paralleling the magnetically suspended spring can reduce the support stiffness of the air bearing to achieve better performance of vibration isolation. In horizontal direction, an auxiliary locater is introduced to reduce the influence of side slanting force. The specially designed handle can be adjusted to different stiffness for different working conditions.Thirdly, a system model of position and vibration active control is established. Not only the position active control method can improve the stable working situation position but also can enhance the positioning accuracy. The vibration active control is crucial to reduce the disturbance to platform. To improve isolation effect, the controller is blending feedback and feedforward.Finally, the position and isolation performance of the system has been tested. The correctness of the principle of the adjustment stiffness was by test and verify. With the position active control, the position accuracy(3?) can reach 3.0μm. The natural frequency can reach 0.93, 1.25 and 2.31 Hz respectively along X, Y, Z axis. The vibration velocity of the vibration isolation platform is 8.77, 10.53 and 4.48μm/s respectively along X, Y, Z axis.