Design And Research On Thrust Fluctuation Of Tubular Permanent Magnet Linear Motors Made Of Soft Magnetic Composite Materials

Linear motion is regarded as one of the most basic motion forms in industrial and life automation systems.And the appearance of linear motor provides a new and more direct method for the realization of linear motion.The structure of traditional ways such as pneumatic,hydraulic,screw is complex and their system efficiency is low.Linear motor can realize linear motion directly without transmissions,so it has many advantages such as simple structure,high speed,high precision,and fast response and so on.Tubular permanent magnet linear motor(TPMLM)has both advantages from linear motor and permanent magnet motor.However,TPMLM has its disadvantages.The problem of large thrust fluctuation directly affects its servo performance.This project is supported by National Natural Science Foundation of China—study on thrust ripple and material iron loss character of TPMLM made of soft magnetic composite materials.In this paper,a TPMLM is designed.According to the main reason of the thrust fluctuation of the linear motor,the motor is simulated and optimized.The work mainly from the following aspects:Firstly,the working principle and structural characteristics of cylindrical permanent magnet linear motor are introduced.Based on the theoretical analysis and calculation,the appropriate motor structure is selected and the basic design method of the motor is determined.Then finite element software Ansoft is used to build the model to verify the rationality of the motor size.Secondly,the main reason of the thrust fluctuation of TPMLM is analyzed.Aimed at two aspects of linear motor end force and cogging force the motor is optimized.The influence of the primary length on the end force is discussed,and the optimum primary core length is obtained.To reduce the detent force,the slot width and secondary magnetization structure of the motor are contrasted and optimal selected.Combined with actual processing problems,the final design scheme of the motor is determined.Compared the new scheme with the original scheme,the effectiveness in reducing motor thrust fluctuation of the new scheme is verified.After testing the detent force of motor,the measured data is compared with the simulation results to verify the theoretical and simulation results.The reasons of the difference between measured data and simulation results are analyzed and the practical experience of prototype making and experiment is summarized.Finally,a new method of analyzing end force of TPMLM is proposed and this method is used to analyze the force of tubular linear motor with oblique end.Then the optimal end size is obtained by using the new method.The method is validated by finite element simulation.In addition,the feasibility of reducing motor thrust fluctuation with skewed slots is also analyzed.Using the finite element simulation software,the thrust fluctuation laws of cylinder linear motor with different angles of skewed slots are studied and analyzed.In this paper,the design and optimization of the motor provides some experimental data and theoretical guidance for the design of tubular permanent magnet linear motor in the future.