| High precision positioning platforms are widely used in industries that require precision processing,such as communications,computers and consumer electronics,etc.With the increase of station on the positioning platform,the operation becomes more and more complicated.The demand for multi-station coordinated operation of platform is increasing.The traditional positioning platforms are limited to linear operation and most transports use belts,drag chains,etc.Such mechanical structure is complex and limited,which has been unable to meet the precision requirements of the precision machining industry.At present,domestic and foreign tend to adopt annular platform for a multi-station coordinated operation,but there is less research on it in China.Therefore,in this paper,the research of the annulus multi-motor positioning platform is conducted.It is mainly studied from the three aspects:electromagnetic analysis,position feedback method and coordinated control method of the platform motor,so as to achieve high-precision positioning of the platform and coordinated control between movers.Firstly,in view of the dragging problem of the dynamic linear motor,dynamic magnetic linear motor is used and the stator coil is designed in sections to reduce energy consumption.The topological structure of the unit motor is analyzed,and the electromagnetic parameters such as the cogging force,thrust,back-EMF and back-EMF harmonic distortion are analyzed by finite element simulation.Secondly,aiming at the problem of motor position feedback,the advantages and disadvantages of various feedback methods are analyzed.The position and speed of movers are detected by using low-cost linear hall position sensor,and perform real-time noise filtering on the measured hall signals and frequency doubling subdivision processing to achieve high-resolution position detection.Then,in order to carry out better coordinated control of multi-motor,the sequence numbers of each mover are coded in binary,so as to acquire the positions of movers in real time.By analyzing the changes of the induced electromotive force when the mover spans two windings,to ensure the thrust stability when the windings are switched.Draw the moving track of the mover to ensure that the mover is free from jitters and jams during the running process.In order to ensure the control precision of the single mover,a magnetic directional control method based on linear hall sensor is adopted.The coordinated control method based on adjacent deviation coupling control is used to improve the synchronization error between multiple movers and ensure the cooperative accuracy of each mover.Finally,on the built moving-coil annular platform,the relevant electromagnetic characteristics of the motor,including back-EMF,cogging force and current were tested,and the positioning accuracy of the mover on the platform is tested.Simultaneously,the linear experimental platform of three motors was built and test the synchronization error to verify the coordination performance of the movers. |
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