| Magnetic levitation vibration isolation platform is a kind of electromagnetic device which uses electromagnetic force to realize levitation,motion and vibration control.Compared with traditional vibration isolation devices,magnetic levitation vibration isolation platform has the advantages of no mechanical contact,no friction,no wear and compatibility with vacuum environment,etc.It has broad application prospects in modern precision and ultra-precision equipment field such as integrated circuit manufacturing,aerospace,biomedicine and so on.In recent years,it has been widely concerned by academia and industry.Non-contact voice coil motor and magnetic levitation gravity compensator are the key devices of magnetic levitation vibration isolation platform to realize levitation.On the basis of summarizing the advantages and disadvantages of the existing structure forms of non-contact voice coil motor and magnetic levitation gravity compensator at home and abroad,this paper presents a new structure scheme of hyperbolic magnetic field voice coil motor and a new structure scheme of rhombus magnet array magnetic levitation gravity compensator to improve the thrust performance of the former and the levitation force performance of the latter.Because the magnetic levitation vibration isolation platform which is composed of hyperbolic magnetic field voice coil motor and rhombus magnet array magnetic levitation gravity compensator achieves stable levitation through the active control force generated by the former and the passive levitation force generated by the latter,it is named as active and passive combined magnetic levitation vibration isolation platform in this paper.In this paper,the active and passive combined magnetic levitation vibration isolation platform,and its key devices,hyperbolic magnetic field voice coil motor and rhombus magnet array magnetic levitation gravity compensator,are taken as the research objects.Through theoretical analysis,numerical calculation and experimental research,the research work is carried out on mathematical modeling,thrust and levitation force characteristics analysis and optimization,electromagnetic design and so on.In this paper,firstly,the basic structure and operating principle of the proposed active and passive combined magnetic levitation vibration isolation platform,and its core devices,hyperbolic magnetic field voice coil motor and rhombus magnet array magnetic levitation gravity compensator,are introduced,and also their mathematical models are established.Considering that the relative motion between the moving parts and the fixed parts of the magnetic levitation system is six-degree-of-freedom motion,the expressions of magnetic field,force and torque of hyperbolic magnetic field voice coil motor and rhombus magnet array magnetic levitation gravity compensator are derived by using the equivalent current method,the coordinate transformation method and Lorentz force method.In addition,the dynamic model of the active and passive combined magnetic levitation vibration isolation platform is established based on rigid body mechanics.The above work lays a theoretical foundation for the follow-up characteristic analysis,optimization and electromagnetic design of the platform and its core devices.In order to improve the system performance,the voice coil motor and magnetic levitation gravity compensator in the magnetic levitation system should have small thrust fluctuation and small levitation force fluctuation,respectively.Therefore,the thrust characteristic of the voice coil motor and the levitation force characteristic of the magnetic levitation gravity compensator are analyzed and optimized in this paper.Based on the analysis of the influence of magnetic field and multi-degree-of-freedom motion on the thrust of the voice coil motor and the levitation force of the magnetic levitation gravity compensator,a voice coil motor based on hyperbolic magnetic field is proposed to reduce the thrust fluctuation through the hyperbolic magnetic field,and a rhombus magnet array magnetic levitation gravity compensator is proposed to reduce the levitation force fluctuation and improve the levitation force density through the rhombus magnet array structure.In addition,the influence of relative permeability of permanent magnet on the levitation force of magnetic levitation gravity compensator and the optimization method are analyzed.In this paper,the electromagnetic design methods of hyperbolic magnetic field voice coil motor and rhombus magnet array magnetic levitation gravity compensator are also studied.Aiming at their application field,the design principles and flow charts of hyperbolic magnetic field voice coil motor and rhombus magnet array magnetic levitation gravity compensator are clarified.On the basis of the mathematical model established above,the main size formulas of the two kinds of electromagnetic devices are deduced.The effects of the basic parameters of the two electromagnetic devices on their performance are summarized,which provides a reference for the electromagnetic design of hyperbolic magnetic field voice coil motor and rhombus magnet array magnetic levitation gravity compensator.On the basis of the above research,the prototypes of active and passive combined magnetic levitation vibration isolation platform,and its core devices,hyperbolic magnetic field voice coil motor and rhombus magnet array magnetic levitation gravity compensator,are developed.The test platforms are built to carry out the experimental research on the thrust of hyperbolic magnetic voice coil motor,and the experimental research on the levitation force of rhombus magnet array magnetic levitation gravity compensator,and also the experimental research on the electromagnetic force/torque decoupling,levitation,six-degree-of-freedom pose adjustment,direct disturbance suppression and indirect disturbance suppression of the active and passive magnetic levitation vibration isolation platform,which verifies the correctness of the theoretical analysis. |
PDF Full Text Request