有限转角力矩电机及其研究发展综述

An Overview on Developments and Research of Limited Angle Torque Motor

有限转角力矩电机(LATM)具有结构简单、控制方便、可靠性高、力矩密度大等优点,因而其作为一种在有限转角内直驱工作的电动作动器已广泛应用于国民经济的诸多领域。该文首先介绍了LATM的理论基础,包括LATM的工作原理、矩角特性、主要拓扑结构及其演变思路,并补充了一些特殊的拓扑结构。其次,归纳了LATM的设计方法,并分析了如何抑制LATM工作区间内的力矩波动、提升区间内的输出力矩以及拓宽工作区间。然后,讨论了LATM在是否考虑非线性时的数学模型与控制方法。最后,对LATM的应用领域进行了归纳和介绍,总结展望了LATM及其相关技术研究的主要发展方向。

A limited angle torque motor(LATM)can rotate around the axis within a certain angle without requiring additional mechanical devices.LATMs are often used as electrically powered actuators,which are applied to the direct drive control with a torque requirement of less than 1 kN·m within a limited angle.Compared with traditional hydraulic and pneumatic actuators,no piping or other transmission equipment is required.Compared with the traditional electrically powered actuator of the rotary motor with gearbox,LATM has no non-linearity problem caused by the transmission mechanism and has the advantages of simple structure,convenient control,high reliability,and high torque density.Therefore,LATMs are widely used in various application fields that require only a limited rotation angle.There are many different structures of LATM and various ways to classify them.At the same time,there are similarities in the working principles of serval main topologies that have been used so far.In this paper,the working principles of each main topology are introduced by evolving the DC motor into these topologies,which leads to the relationship between output torque and rotor angle,the characteristic of most interest in applications of LATM.Then,various LATM topologies and their characteristics are presented in detail.Among these topologies,the toroidal slotless LATM and equi-polar slot LATM are the two most widely used topologies and research focuses.The torque-angle characteristic of LATM has a constant torque range(CTR),where the output torque is proportional to the input current and independent of the speed and rotor position.Thus,it is the operating range of LATM.The magnitude of CTR and the maximum output torque in the range are the two most important static performance indicators of LATM.Since CTR is affected by the cogging torque,armature reaction,and nonlinearity of the ferromagnetic material,this paper presents the application of the equivalent magnetic circuit methods,the analytical methods,the finite element method,and the decision-making methods in LATM design.Moreover,this paper discusses how to suppress the torque ripple within CTR and how to further improve the magnitude of CTR and the maximum output torque in the range.Mathematical models and control methods are indispensable to achieving precise control of LATM.The linear mathematical model can be analogous to that of a DC motor.However,accurate nonlinear mathematical models must rely on the finite element method or experimental data.Thus,robust control methods are better for obtaining the desired dynamic performance.This paper presents the application of PID and improved PID control methods in LATM control,and the application of various modern control methods considering the effects of load disturbances,motor parameter variations,and nonlinearity of the torque-angle characteristic.According to the swing scanning and positioning functions of LATM,three typical application fieldsimaging system,servo valve,and aircraft attitude-are detailed in this paper,and other applications are roughly introduced.With the development of science and technology,the study of new structures,optimization of the torque-angle characteristic,loss calculation,multi-physics field coupling analysis,and testing techniques will become the main development trend in LATM research.As researchers improve motor performance,LATM will have a broader application prospect.