行波型杆式超声电机定子的参数化有限元法优化设计

摘要：利用参数化有限元优化方法,对行波型杆式超声电机定子进行优化设计。首先,在确定电机定子初始结构的基础上,建立其参数化有限元模型。其次,对定子有限元模型进行模态分析,求解工作模态频率对各结构参数的灵敏度,选取灵敏度高的结构参数为设计变量,并以反映电机输出性能的重要参数作为目标函数。同时,设计了定子结构的优化方案,采用了零阶优化方法,对其结构进行优化设计。最后,根据优化结果,制作了定子样机。试验表明：定子工作模态和端面质点的振幅都满足了预期的设计要求,试验结果与优化设计结果相符。研究表明,利用该优化设计方法能有效地缩短超声电机设计周期。     

纵弯模态复合型直线超声电机定子质心振动研究

针对纵弯模态复合型直线超声电机的质心振动问题,采用等效非线性弹簧层接触理论,建立了刚性平面接触模型和定子法向运动的动力学模型,进而解出一阶纵振模态和定子质心振动的动力学方程,得出质心振动的稳态解。根据建立的模型,分析了定子质心振动对电机机械输出性能的影响;并通过MATLAB仿真计算进一步分析了预压力弹簧刚度、预压力大小等因素对定子质心振动响应的影响。最后制作样机并开展了实验研究。实验表明模型是有效的,该研究可以为直线超声电机的动力学建模和结构优化设计提供理论依据。     

基于ANSYS的车用交流发电机定子建模方法分析

为了准确预测车用交流发电机的振动和噪声,需要得到电机定子准确的模态特性,而准确的仿真计算模态前提是要有准确的仿真模型。利用有限元软件ANSYS对定子铁芯分别建立实体与片状结构模型计算得到模态特性,并结合实验结果确定定子铁芯采用实体结构模型与实际最接近且计算最简便。在确定定子铁芯建模方法的基础上,对绕组通过不同的等效方式组成不同的定子模型来计算得到不同的定子模态结果,结合实验结果来选取最符合实际的模型,从而确定绕组采用等效体积的方法与实际最接近,最终确定电机定子的建模方法,为后期仿真计算的有效性提供依据。     

硅钢片固结方式对新能源汽车电机模态特性影响的研究

新能源汽车优点突出，成为各国近来新车发展的主流。电机转速的提高使得工作频率不断升高，容易与定子发生高频共振。定子铁芯的加工工艺会影响定子的模态频率，直接对定子进行数值分析会耗费大量计算资源与时间成本。因此，针对粘接定子的动力学建模运用叠片理论、针对焊接定子的简化建模基于半有限元方法，然后利用定子的模态实验验证了所建模型的准确性，最后针对焊接定子提出了减振降噪的结构优化设计。结果表明，固结方式直接影响定子的刚度而对其动力学特性产生巨大影响；提出的两种建模方法结果精确，在电机设计初期具有指导意义。     

基于ICM准则法的结构动力学边界拓扑优化设计

针对结构动力学边界条件,进行了基于固有频率和振型特定要求的结构动力学边界条件优化设计研究。建立了以结构振型差的范数为目标函数,结构固有频率为约束条件的动力学边界条件设计准则。根据实际结构在设计的约束条件范围内可能变更的方案,通过不断修改设计参数,确定满足结构动力学要求的方案。采用ICM准则法对刚架边界的机翼骨架模型进行了动力学边界的拓扑优化设计,数值模拟算例验证了该方法用于动力学优化设计的可行性。     

超声电机定子热机电耦合特性

应用于极端环境的超声电机会受到温度场、应力场和电场的共同作用,定子在热机电耦合激励下的响应与电机工作特性密切相关.以行波型旋转超声电机为对象建立定子的能量泛函,采用假设模态的方法得到了热机电耦合动力学模型.运用有限元方法对热机电耦合作用下的定子进行仿真,分析了与理论计算结果的差异.建立了定子热扫频试验平台和热变形试验平台,测定温度对定子稳态形变、模态频率和振幅的影响,对理论模型的分析方法进行了评价.理论分析和试验结果揭示了超声电机定子在热机电耦合作用下的振动行为的变化规律,为下一步极端环境超声电机的设计和优化提供了依据.     

永磁直流无刷电机定子振动动力学分析及实验研究

在集中驱动的电动汽车中,电机是电动汽车振动和车内外噪声的主要源头之一。因此,设计人员都期望于在设计阶段能对电机的振动噪声性能进行分析。本文基于电磁场分析理论对电动汽车驱动用永磁直流无刷电机径向力波进行了有限元仿真计算,进而对电机定子进行了动力学建模与仿真研究,实现了车用定子振动动力学特性分析。仿真结果与电机振动试验结果相符,验证了分析的正确性,为进一步实现低噪声驱动电机的优化设计打下了基础。     

电机定子铁芯振动特性分析的一种解析方法

随着新能源汽车的发展,用户对电机噪声的要求日趋严格,噪声振动分析已经成为电机开发中的重要内容。定子的电磁振动是电机的主要噪声源,由于电机定子的复杂结构,目前常用有限元方法建模分析定子铁芯的振动特性,耗时太长,不能满足定子优化设计的振动噪声特性快速计算要求。提出了一种解析方法用于计算定子铁芯的振动特性。采用厚壳-梁耦合结构对定子铁芯进行简化,计入了定子齿对振动特性的影响;推导了耦合结构的解析能量泛函,并使用Rayleigh-Ritz法计算出定子铁芯的固有频率和模态振型。应用该解析方法计算了电机定子振动特性,分析了定子齿枢的影响,并与商用软件的有限元建模分析结果进行比较,两者误差小于5%,验证了该解析方法的准确性。     

旋转型行波超声电机定子的子结构模型研究

按照旋转型行波超声电机定子的结构特点将其划分为几个较简单的子结构,分别对其进行了动态特性分析,最后在子结构模态综合法的基础上建立了整个定子的分析模型。该模型可以很方便地计算电机定子的各阶模态,并且由于运用Guyan静力法将定子齿单元的刚度和质量凝聚到基体之上,不仅恰当地描述了齿对定子动态特性的影响,而且达到了缩减计算量的目的。通过算例和实验说明此理论模型是可行的,可用于电机系统性能预测和参数优化设计。     

盆架型压电平面电机响应面法动力学特性优化

为解决压电电机定子在设计过程中存在的定子结构尺寸难以拟定、驱动足激励变形难以最大化以及进行多目标设计时难以求得全局最优解等问题,以盆架型压电电机定子为研究对象,在以有限元法构造定子参数化模型的基础上,利用模态置信准则(modal Assurance Criterion,MAC)进行定子工作模态的筛选与捕获,采用中心复合设计法(Central Composite Design,CCD)生成采样计算点,结合克里金法(Kriging Method)搭建相关特征结构尺寸参数的响应面优化模型,并运用多目标遗传优化算法(Non-dominated Sorting Genetic Algorithm-Ⅱ,NSGA-Ⅱ)在基于响应面模型所得的设计空间内进行最优解的全局搜索。通过定子谐响应分析得到弯-纵振频差相对于“试凑法”所得结果下降30 %,且无明显干扰模态,由此验证了优化模型的正确性。瞬态分析结果表明定子驱动足的x 方向位移为6.4 μm,y 方向位移为5.48 μm,z 方向位移为6.16 μm,各相位移均有明显增长。说明根据优化设计得到的定子驱动足位移更大,三相工作模态更接近,电机运行更加平稳。     

二自由度行波型超声波电机定子的数学模型与实验研究

二自由度行波型超声波电机是一种新型多自由度超声波电机。本文从二自由度行波型超声波电机的驱动机理和基本结构出发,就电机的结构实现、驱动球转子的最佳定子结构进行了分析,利用所建立的有限元模型进行定子振动的模态分析和共振频率计算,提出了外缘大倾角内缘线接触的行波定子。然后建立定子的接触模型,对其机械性能进行分析。测试结果表明,修正的数学模型更加符合电机的实际运行特性。所研制样机的球转子直径为45mm,定子直径为30mm,实现的堵转力矩为120mNm,空转转速12r/min。本文工作为多自由度行波型超声波电机的优化设计、性能提高奠定了基础。     

Y形旋转超声波马达的设计与动态特性分析

为了探索和丰富旋转超声波马达的结构,使其满足响应精准且速度快以及控制简便的要求,设计了Y形旋转超声波马达,并对其结构及动态特性进行了分析。Y形旋转超声波马达将3组压电陶瓷片的横向振动复合成驱动足端面对转子的微幅驱动,通过摩擦耦合在惯性作用下推动转子顺时针或逆时针旋转。运用Workbench软件中的Design Exporation组件对Y形旋转超声波马达定子组件的结构尺寸进行了优化设计,提升了定子组件的性能。构建优化后Y形旋转超声波马达定子组件的有限元仿真模型,并通过模态分析获得了定子组件工作所需的固有振型,通过谐响应分析获得了定子组件的幅频特性曲线,通过瞬态分析获得了1个激励周期内定子组件的振动模态,验证了Y形旋转超声波马达的驱动机理。结果表明,Y形旋转超声波马达压电陶瓷片表面施加电压的最佳频率为20 739 Hz,对应的驱动足端面的振幅为6.95 μm。Y形旋转超声波马达结构简单且具有对称性,能效利用率高,对拓宽超声波马达的应用领域有重要参考价值。     

Nonlinear dynamic analysis of traveling wave-type ultrasonic motors

In this paper, nonlinear dynamic response of a traveling wave-type ultrasonic motor was investigated. In particular, understanding the transient dynamics of a bar-type ultrasonic motor, such as starting up and stopping, is of primary interest. First, the transient response of the bar-type ultrasonic motor at starting up and stopping was measured using a laser Doppler velocimeter, and its driving characteristics are discussed in detail. The motor is shown to possess amplitude-dependent nonlinearity that greatly influences the transient dynamics of the motor. Second, a dynamical model of the motor was constructed as a second-order nonlinear oscillator, which represents the dynamics of the piezoelectric ceramic, stator, and rotor. The model features nonlinearities caused by the frictional interface between the stator and the rotor, and cubic nonlinearity in the dynamics of the stator. Coulomb's friction model was employed for the interface model, and a stick-slip phenomenon is considered. Lastly, it was shown that the model is capable of representing the transient dynamics of the motor accurately. The critical parameters in the model were identified from measured results, and numerical simulations were conducted using the model with the identified parameters. Good agreement between the results of measurements and numerical simulations is observed.     

Coupled tangential-axial resonant modes of piezoelectric hollow cylinders and their application in ultrasonic motors

This paper describes a tangential-axial eigen-mode of a piezoelectric hollow cylinder. A new type of piezoelectric ultrasonic motor using this oscillation mode has been developed. The motor is a traveling-wave-type motor. The stator of such a motor consists of a solid piezoelectric hollow cylinder, which, excited in the tangential-axial resonant mode by a three-phase electrical signal, will exhibit elliptical displacement and transfer rotation to the rotor. The behavior of the stator has been simulated with finite element method (FEM) software. The simulation results have been checked with single-point contact measurements on the surface of the ultrasonic motors. The paper closes with the introduction of new ultrasonic motors based on this oscillation mode.     

Modeling of a piezoelectric rotary ultrasonic motor

A piezoelectric rotary ultrasonic motor is modeled for the purpose of predicting, a priori, motor performance as a function of design parameters. The Rayleigh-Ritz assumed mode energy method is used to model the distributed piezoceramics and the traveling wave dynamics of the stator. Natural frequencies and modeshapes are obtained for a generally configured motor. Nonlinear normal and tangential interface forces between the rotor and stator are incorporated into the forcing function along with the linear piezoelectric forcing. Given the applied torque, applied axial loading, and piezo drive voltages as inputs to the model, general motor performance measures are obtained-namely speed, input power, output power, and efficiency. The approach presented here provides a general framework for modeling these motors as well as a design tool for optimizing prototypes with the added flexibility of allowing for a wide variety of geometries and materials     

Traveling-wave piezoelectric linear motor. I. The stator design

A new type of piezoelectric linear motor incorporating a traveling wave has been developed. The linear motor is comprised of a stator and a carriage. The stator design, which consists of a meander-line structure and gear teeth mounted on the meander-line structure, is the focus of this article. The meander-line structure is constructed with bimorph actuators arranged in a line. These actuators are driven by two phased sets of alternating current (ac) in order to generate a traveling wave. The traveling wave is transferred to the gear teeth, by which the carriage is driven. Modeling of the stator is derived by use of a strain energy method. The performance of various materials is evaluated by analytical and experimental methods. The analytical and the experimental results are quite approximate. Modal analysis is investigated using ANSYS. Appropriate modes associated with ultrasonic levels of resonant frequency are selected to obtain desired motion and to enhance the output performance. Surface speed for various applied input voltage are studied and indicate a nearly linear relationship. The stator in combination with the carriage makes up the linear motor     

Traveling-wave piezoelectric linear motor Part I: the stator design.

A new type of piezoelectric linear motor incorporating a traveling wave has been developed. The linear motor is comprised of a stator and a carriage. The stator design, which consists of a meander-line structure and gear teeth mounted on the meander-line structure, is the focus of this article. The meander-line structure is constructed with bimorph actuators arranged in a line. These actuators are driven by two phased sets of alternating current (ac) in order to generate a traveling wave. The traveling wave is transferred to the gear teeth, by which the carriage is driven. Modeling of the stator is derived by use of a strain energy method. The performance of various materials is evaluated by analytical and experimental methods. The analytical and the experimental results are quite approximate. Modal analysis is investigated using ANSYS. Appropriate modes associated with ultrasonic levels of resonant frequency are selected to obtain desired motion and to enhance the output performance. Surface speed for various applied input voltage are studied and indicate a nearly linear relationship. The stator in combination with the carriage makes up the linear motor.     

考虑驱动和负载状态的三自由度超声电机接触模型研究

建立了一种考虑不同运转情况的对于三定子多自由度超声电机的接触模型。介绍了三自由度超声电机的基本原理和结构并计算得出了其驱动转矩,引入Hertz接触理论和Mindlin理论对摩擦情况进行分析,考虑了摩擦因数的动态非线性和摩擦力分布的非线性变化,提出了一种新型的接触模型,改进了传统的线性摩擦模型;通过转矩关系和摩擦模型对电机不同运动情况下摩擦力分布进行分析,并用Matlab绘制相应的摩擦力分布图。分析结果验证了三自由度超声电机合理性,说明了三相压电定子接触状态根据驱动情况和负载而定,为进一步的优化设计和性能改进奠定了基础。     

圆盘型非接触超声波马达定子的振动模拟与测试

介绍一种圆盘型非接触超声波马达的结构。利用有限元法计算了超声波马达定子在不同振动模态下的固有频率,并用激光测振仪对定子进行了测试,结果两者吻合较好。由于振幅和非接触马达的声辐射压力密切相关,因此通过谐响应分析计算了定子的振幅与定子驱动电压的关系,从而为马达的实验研究提供了理论依据。在最优模态B21下进行转子转速测试,测得最高转速为1600rpm。