Electromagnetic Performance Analysis And Magnetic Flux Leakage Research On Permanent Magnet Motor For Manipulator

In recent years,China and some developed countries in the world have been relentlessly exploring outer space.Space equipment in the outer space needs to rely on mechanical execution device when completing the operation.Space manipulator is the most important one.Both manipulators in or out of the cabin consist of a motor unit,a control unit and a drive unit.In order to run smoothly and accurately,the motor unit should be well driven,the transmission unit should be accurately operated and the control unit should be well controlled.This paper focuses on the optimization of the motor structure in the motor unit and the electromagnetic interference shielding measures for the control unit.Firstly,the principle and working condition of each unit of the manipulator are studied,and the demands of the manipulator for each unit are obtained.The classification of electromagnetic shielding is studied so that shielding measures can be applied to the sensor in the control unit.The position of the Hall sensor in the motor is analyzed,and the Hall sensor placement scheme for the motor unit is obtained.Based on the finite element simulation,the influence of the pole slot ratio,the air gap length and the slot width on the motor performance is analyzed.The motor structure suitable for the joint of the manipulator is obtained.By comparing the Hall sensor in the conventional position and the stator slot position,the finite element simulation results of the no-load and the load condition under the two sensor positions are obtained.The mechanical properties of the Hall sensor in the stator slot position are studied experimentally.The symmetrical and asymmetrical conditions of the three-phase winding of the motor are analyzed.The asymmetric three-phase winding method of the motor is studied.Through finite element simulation,no-load and load operation situations of symmetrical and asymmetrical winding motors with same size are analyzed.The applicability of asymmetrical winding for the high power density manipulator is analyzed.The magnetic encoder of the manipulator joint control unit has a high sensitivity but withstands less electromagnetic interference.In the manipulator joint,the flux leakage caused by end of the motor winding has the greatest impact on the sensor.Based on the finite element analysis method,in the two-dimensional field,qualitatively analyzed the effectiveness of the shielding measures for the end of the motor winding.In the three-dimensional field,the paper accurately analyzed the interference shielding effectiveness under different current excitation.