Research On Tolerance Selection Of Permanent Magnet Synchronous Linear Motor Based On Performance Optimal Criterion And Taguchi Quality Loss Model

Air-core permanent magnet synchronous linear motors(PMSLMs)can directly achieve linear motion without middle mechanical conversion device.The PMSLMs have the characteristics of high efficiency,good dynamic response effect and high precision positioning etc.Due to these characteristics,PMSLMs have wide application prospects in high precision laser processing,3D printing,glass substrate detection and other industrial automation.However,when select the dimension tolerance of the motors parts,the thrust performance and comprehensive cost cannot consider comprehensively,resulting in unreasonable dimension tolerance selection results and cannot achieve maximized economic benefits.Therefore,this paper investigates the optimal dimensional tolerance selection of the permanent magnet synchronous linear motor.Under the premise of the lowest comprehensive cost,to achieve the optimal thrust performance of the motor,the optimal dimension tolerance of the part is selected.This paper investigated the air-core PMSLM optimal tolerance selection,which are applied in the high-precision laser cutting machine.Aim at the batch production of the motors,the optimal tolerance selection of air core PMSLMs is investigated.On the basic of the structural characteristics of the air core PMSLM,the analytical analysis model was established,the dimension tolerance was analyzed,the high-precision thrust prediction model was established,the dimension tolerance sensitivity was analyzed,the comprehensive cost function was established,and the dimension tolerance of the key structures were determined.The ideas and methods were verified through FEA model and PMSLM prototype experiment.It provides a new idea and method for selecting the dimensional tolerance of the parts,improving the thrust performance and extend the service life of the motor within the limited manufacturing cost.The optimal dimension tolerance selection of the air core PMSLM is mainly carried out as follows:(1)Based on the bilateral symmetrical structure of the iron-core PMSLMs,the equivalent magnetization intensity method was introduced to analyze the air gap magnetic field distribution characteristics of the motor and the analytical model of the motor is established.The thrust performance variation trend under the influence of different dimension tolerance of the parts were investigated,it provided a theoretical support for subsequent motor tolerance optimization selection.(2)From the perspective of manufacturing,the source of the part was analyzed,and the component loop and closed loop are determined according to the dimension chain,and the error transmission and error accumulation were analyzed.Combined with the analytical results,the key structural parameters are determined.The thrust performance of different parameter combinations was obtained by FEA method,and the sample database was established.The extreme learning machine was introduced to establish a high-precision thrust performance prediction model based on the sample data.(3)The concept of Taguchi quality loss was introduced to describe the relationship between the quality loss cost of the motor thrust and the dimension tolerance of the structural parameters.The Taguchi quality loss model between the quality loss of the motor and the dimension tolerance was established based on dimension tolerance sensitivity analysis.Combined with the manufacturing cost model,the comprehensive cost model was established.The genetic algorithm(GA)method was introduced to optimize the dimension tolerance,under the premise of the lowest comprehensive cost,the optimal part dimension tolerance makes the motor’s thrust performance.According to the standard tolerance class table,the tolerance class is determined.The tolerance degree was determined based on the standard tolerance table.(4)On the basic of the selection result of the dimensional tolerance,the rationality of the tolerance range was verified through FEA analysis and PMSLM prototype experiment.The upper and lower limit deviations of the dimension of the parts are verified through FEA analysis,and compared with motor thrust performance under target dimension.According to the selected tolerance level,the PMSLM experiment prototype was built.The thrust performance of the motor under different dimension tolerance combinations were collected.Based on the experiment data,the accuracy of the ELM model was verified and the dimension tolerance sensitivity is determined.Further,the thrust performance under the influence of the up deviation,low deviation and the middle deviation of the motor were verified.The no-load induced electromotive force was analyzed either.