Optimum Design And Performance Study Of Rotary Electro-mechanical Converter Based On Air Gap Compensation

The electro-hydraulic servo control system has many advantages,such as high control precision,fast response speed and strong carrying capacity.It is widely used in aerospace,transportation,construction machinery and other industrial fields.Electro-mechanical converter is a key component of electro-hydraulic servo system.It converts electrical signal into mechanical motion,and then controls the motion of electro-hydraulic servo valve.Its performance has great influence on the performance of electro-hydraulic control system.In order to popularize and apply electro-hydraulic servo technology better,scholars at home and abroad have done a lot of research on the optimization of magnetic circuit topology and torque-angle characteristics of electro-mechanical converters.The cross section of the air gap of traditional rotary electro-mechanical converter is mostly a rectangular end face.The armature swings in high frequency and small amplitude near zero position,with small rotation angle,low linearity and small linear range.The single radial annular working air gap has a positive magnetic spring stiffness,although it can have a larger working angle,but with the increase of the angle,the output torque will gradually decrease.In this paper,a method of adjusting the torque-angle characteristics of rotary electro-mechanical converter based on air gap compensation is presented.By designing appropriate compensation air gap,increasing output torque and improving its torque-angle characteristics,a bidirectional rotating electro-mechanical rotation with horizontal torque-angle characteristics and simple structure based on mixed air gap is obtained.The main research contents of the converter are as follows:1.According to the theoretical basis of electromagnetic field,the magnetic circuit analysis of radial air gap and mixed air gap rotary electro-mechanical converter is carried out,and the static mathematical models are obtained respectively,and thecomparative analysis is carried out,which provides the theoretical basis for subsequent finite element simulation and experimental research.2.Based on Maxwell finite element software,the radial air gap and mixed air gap rotary electro-mechanical converter are simulated by finite element method.The effects of different physical structure parameters on the torque-angle characteristics of the hybrid air gap rotary electro-mechanical converter are analyzed,and its transient characteristics are compared and studied.The results show that the objective of increasing the output torque and improving the static performance of rotary electro-mechanical converter can be achieved by optimizing the parameters.3.The prototype of rotary electro-mechanical converter before and after air gap compensation is processed and the experimental bench is built.The torque-angle characteristics,current-torque characteristics and step response characteristics of rotary electro-mechanical converter are studied respectively.The experimental results are in good agreement with the theoretical analysis.It is shown that the rotary electro-mechanical converter can obtain near-horizontal torque-angle characteristics through reasonable parameter optimization.Air gap compensation is beneficial to increase the output torque and obtain good static characteristics.The proportional position control characteristics can be obtained by adding linear springs.