Contact analysis and modeling of standing wave linear ultrasonic motor

A contact model for describing the contact mechanics between the stator and slider of the standing wave linear ultrasonic motor was presented. The proposed model starts from the assumption that the vibration characteristics of the stator is not affected by the contact process. A modified friction models was used to analyze the contact problems. Firstly, the dynamic normal contact force, interface friction force, and steady-state characteristics were analyzed. Secondly, the influences of the contact layer material, the dynamic characteristics of the stator, and the pre-load on motor performance were simulated. Finally, to validate the contact model, a linear ultrasonic motor based on in-plane modes was used as an example. The corresponding results show that a set of simulation of motor performances based on the proposed contact mechanism is in good agreement with experimental results. This model is helpful to understanding the operation principle of the standing wave linear motor and thus contributes to the design of these types of motor.     

环状压电超声电机的多频率驱动分析与实验

针对压电超声电机的多频率驱动问题进行研究,设计并制作了利用定子内圆周面驱动的环状压电超声电机,明 确了利用行波驱动电机转子的机理。通过有限元计算给出了电机定子所用弯曲模态的振型与位移云图。以计算结果为基础, 分析了电机所用的压电陶瓷片的极化分区与定子弯曲模态激发之间的关系,得出了所用的压电陶瓷片能够实现电机多频率转 动的结论。完成了所研制的超声电机的多频率驱动实验。实验结果表明,电机能够实现在多频率点的转动。依据本文分析思 路,可以对其他结构形式的超声电机的多频率驱动问题进行研究。     

振片式超声波马达的研究

超声波马达是一种由超声振动而获得驱动力的新型马达。它利用作为定子的压电陶瓷振子,通过压电效应产生高频振动并依靠摩擦力来驱动压置在其上的转子运动。     

空间两连杆柔性构件弯扭耦合振动主动控制

为了研究空间柔性结构的耦合振动，提出一种由柔性杆和柔性梁组成的两连杆柔性构件系统，对此柔性构件系统的弯扭耦合振动进行了研究，运用拉格朗日方程和假设模态法推导了此柔性系统的动力学方程．在柔性杆根部粘贴一只压电扭转驱动器抑制柔性杆的扭转振动，在柔性梁根部粘贴一只压电剪切驱动器抑制柔性梁的弯曲振动．采用一种基于Lyapunov稳定性的速度反馈控制策略进行了实验仿真研究．结果表明, 施控后的系统是稳定的，弯扭的各阶模态均能得到有效抑制，柔性梁末端的位移振动能得到显著衰减．     

超声波轴承用压电换能器模态分析及实验研究

设计了超声波轴承用压电换能器,确定所采用的压电换能器的相关参数,并采用有限元法进行压电换能器的振动模态分析,确定压电换能器辐射端面与其他零件组成摩擦副时产生最佳减摩效果的振动模态,并通过实验研究加以验证.研究表明,压电换能器处于纵向振动状态时产生的减摩效果最好.实验证明,超声振动具有良好的减摩性能,同种材料形成的摩擦副,在超声振动状态下静摩擦系数比非振动状态下降低了70%.     

Working principle and design of a double cylinders type traveling wave ultrasonic motor using composite transducer

A double cylinders type traveling wave ultrasonic motor using composite transducer was proposed.The proposed stator contained two cylinders and one composite transducer,and the transducer located on the outer surfaces of cylinders.The composite transducer included two exponential horns located on leading ends,and the horns insected with the cylinders at tip ends.Two degenerated flexural vibration modes spatially and temporally orthogonal to each other were excited in each cylinder by the composite transducer.In this new design,a single transducer could excite two flexural traveling waves in the cylinders.Thus,elliptical motions were achieved at the particles on the teeth.The working principle of the proposed motor was analyzed.The cylinder and transducer were designed with FEM.The resonant frequencies of two vibration modals of the stator were tuned to be the same,and the motion trajectories of nodes on the teeth were analyzed.Transient analysis results show that the motion trajectories of teeth are ellipses.The results of this paper can guide the development of this new type of ultrasonic motor.     

U形直线超声电机结构设计

针对直线超声电机的小型化问题,提出一种新型U形直线超声电机,该电机由U形定子和导轨组成,压电陶瓷片采用粘贴的方式固定在定子上.研究了电机的激振方式与位置,设计并加工了直线超声电机样机和测试装置.将柔性铰链结构应用到直线超声电机夹持中.通过实验确定了电机的最佳工作频率、预压力.研究了输出力和空载速度随工作频率、预压力和电压的变化规律.实验表明,电机在电压值400 Vpp,预压力25N条件下,最大空载速度470 mm/s,最大输出力9N,定子质量25 g,推重比达36;柔性夹持能提高电机的模态一致性和效率,同时简化了电机结构.该研究为电机小型化发展奠定基础.     

超声波电动机定子振动能量回收转换特性

为了向密封、恶劣等极端环境中工作的微型机器人提供驱动力矩和电能,根据行波型超声波电机定子孤极频率反馈跟踪原理,研制能量回馈型超声波电机.与传统超声波电机相比,该电机不仅具有驱动功能,还具有将定子振动能量回收并转换成电能的功能.根据能量回馈型超声波电机驱动原理改进了超声波电动机压电陶瓷的极化分区模式,将超声波电机定子压电陶瓷极化分成3个区,即：激振区、能量采集区和传感区（孤极）.利用定子能量采集区压电陶瓷的正压电效应采集回收超声波电动机定子的机械振动能量.根据铁摩辛柯梁理论和压电本构方程建立超声波电动机定子振动能量采集回收的理论分析模型,研究能量采集区压电陶瓷负载阻抗的匹配问题.利用该模型仿真分析了电机激励频率、激振电压、外接负载电阻等对能量采集区压电陶瓷输出电压、输出电流和输出功率的影响规律,通过实验验证了仿真结果的正确性.     

A new hybrid piezoelectric ultrasonic motor with two stators

A new hybrid piezoelectric ultrasonic motor, which consists of one rotor and two stators, was proposed in this paper. In order to match the resonance frequencies of longitudinal vibration and torsional vibration excited in the stators, a symmetrical structure was adopted in design of the motor. A so-called mass matching method, namely adding two rings to the outside circumference of the two stators respectively, was used to adjust the resonance frequencies of these two vibrations. A finite element model was developed using ANSYS software for the purpose of analyzing the resonance frequencies of longitudinal vibration and torsional vibration as well as the function of the adjusting rings. The results show that the resonance frequency of torsional vibration varies with the position of the ring, but the resonance frequency of longitudinal vibration changes little. By means of adjusting the mass and the position of the rings, the first order resonance frequency of longitudinal vibration is coincided with that of torsional vibration and the value is 20.75kHz. An experimental prototype motor was fabricated according to the analytical results and its performance is in agreement with the theoretical predictions. The speed of motor reaches the maximum 92r/min at the working frequency 19.0kHz.     

复合型USM压电扭振子设计及其特性分析

介绍利用国产压电材料设计纵扭复合型超声波电机(USM)压电扭振子的理论和制造工艺,主要内容包括:压电材料的选取,压电扭振子的结构,根据等效电路推导出电机扭转振动模式的谐振频率方程,以及扭振子尺寸计算公式;根据实验总结了压电扭振子的制造工艺、黏接及其注意问题.并利用阻抗频谱分析仪测试了按上述理论设计的压电扭振子的频率特性.结果表明:设计理论、黏接剂的选择以及加工方法是合理可行的.据此研制的样机最大输出力矩已达10 Nm以上.     

双振子自走型直线超声电机的研究

设计了一种双振子自走型直线超声电机,电机的定子由2个同轴的对称布置的弯曲摇头型振子和中部带细颈的柔性振动块组成.2个振子的弯曲振动会激励出中间振动块的摇头振动,使驱动头上的质点产生椭圆运动轨迹,与导轨摩擦接触产生自走直线运动.测量得到定子上振动块的局部弯曲共振频率为20 792Hz,定子的弯曲共振频率约为40 420Hz.仿真发现,以振动块的局部弯曲共振模态作为工作模态能够得到更大的振幅.实验结果表明,在该模态频率下,电机可以提供较大的驱动速度,发热很少,较长时间工作仍旧稳定可靠,故被选作工作模态.在40 420Hz附近电机能够驱动,但是振子发热严重,不易稳定工作.当两相驱动信号的频率为20.8kHz、相位差为90°、驱动信号电压的峰峰值为138V时,电机的驱动速度达到598mm/s,电机的最大驱动力达到1.94N.     

基于粒子群的压电结构多目标同步优化控制

为了分析压电智能结构振动主动控制中结构与控制的耦合特性,克服现用优化算法的复杂性,以压电智能梁结构为研究对象,运用粒子群优化方法对传感器与作动器分布和反馈控制增益进行同步优化.选用储存能量和控制能量最小以及振动衰减最快的多重性能指标作为优化目标函数,找出了针对特定振动模态下的最佳贴片位置与控制增益,分析了压电片长度和数量对控制效果的影响.运算结果表明,与传统遗传算法相比,粒子群具有编程简单、计算量小、收敛速度快等优点.仿真结果显示,基于粒子群同步优化后的结构振动控制效果明显,验证了该方法的可行性.     

基于精细积分的压电层合板有限元分析及振动控制

文章基于三阶剪切变形理论,建立了压电复合材料层合板有限元单元模型,利用Hamilton原理推导了压电层合板结构的动力学方程,通过引入精细积分方法,利用所建立的单元对压电层合板结构进行了振动分析;基于精细积分给出了线性二次最优控制的Riccati方程的求解方法,设计了线性二次最优控制律以抑制压电层合板结构的振动。实例证明,与其它有限元模型进行比较的结果显示所建立的模型具有足够的精度,文中推导的线性二次最优控制Riccati方程的计算方法可行,对板结构的振动控制有效。     

A novel traveling wave ultrasonic motor using a bar shaped transducer

A novel traveling wave ultrasonic motor was proposed. The structure of the motor is rather simple and different from the conventional traveling wave ultrasonic motors. Its production processes are very convenient. It is composed of a stator constituted with a ring and a bar shaped transducer and two cone shaped rotors. The rotors were pressed on inner surface of the ring by means of a pre-pressure system. The bar shaped transducer has a sand- wich-like configuration,where two sets of piezoelectric element are bolted. One set excites a longitudinal vibration of the bar, and the other set excites a flexural vibration of the bar. The ring＇s traveling wave excited with the longitudinal vibration and the bending vibration of the bar transducer was simulated with FEM （finite element method）. The prototype of the motor was made and investigated experimentally for its performance. Its maximum torque and rotating speed are 0.25 N · m and 50 r/min, respectively.     

平板形单振子多自由度压电马达

对提出的一种平板形单振子多自由度压电马达进行了理论设计和试验研究。利用梁函数组合法,计算了压电马达的工作模态频率,得出了布置于马达压电振子表面的各凸起之间间距的设计依据;提出凸起的尺寸应使其一阶弯曲振动频率与整个压电振子工作频率一致,给出了各凸起尺寸的选取原则。根据设计理论,制作了马达样机,对样机的运动能力进行了试验测试。结果表明:马达工作模态频率的理论计算结果接近于实测值;当驱动电压为90V、频率为45kHz时,马达绕矩形板压电振子长度方向轴向的转速为45.6r/min。     

新型压电输送振子振动模态有限元分析

利用ANSYS有限元分析软件,对用于行波型超声物料输送装置的压电输送振子进行了模态分析,讨论了压电输送振子结构参数对振动模态的影响,为压电输送振子进一步的结构参数修改提供了指导,为行波型超声物料输送装置的设计奠定了基础。     

A ring type standing wave ultrasonic motor using cantilever type longitudinal transducers

The disadvantages of classic ring type ultrasonic motor were analyzed.To obtain large mechanical output power,a ring type standing wave ultrasonic motor using cantilever type longitudinal transducers was proposed.There are four pairs of cantilevers on one side of the ring,and four PZT ceramics are set between each pair of cantilevers.A screw fastened the PZT ceramics and cantilevers together to form a longitudinal transducer.The bending vibration mode of the ring is excited by the stretching vibration of the PZT ceramics.Thus,linear simple harmonic motions are achieved at the particle on the teeth.And the driving force is the frictional force between rotor and stator.The working principle of the proposed motor was analyzed.The ring and the longitudinal transducer were designed with FEM.The sensitive parameters of resonant frequency of the transducer and ring could be gained with modal analysis.The longitudinal vibration modal of transducer and bending vibration modal of ring were degenerated,and the motion trajectories of nodes on the teeth were analyzed.The results of this paper could guide the development of this new type of motor.     

基于压电堆的网壳振动智能控制研究

利用压电材料的压电效应机理,设计出一种压电主控作动杆件,分析其工作原理和设计方法.然后利用模糊智能控制进行仿真,将其应用于网壳结构振动智能控制分析中,结果表明压电主控作动杆可有效地减小结构的加速度和位移响应,为其在桁架结构中的应用打下良好的基础.     

贴片式纵弯复合激励圆筒超声电机

为了有效提高贴片式环形行波超声电机的机械输出性能,利于超声电机的小型化和微型化,研制了一种贴片式纵弯复合激励圆筒超声电机,电机利用d33工作模式和d31工作模式,由单臂变幅杆和一个环形换能器构成,且变幅杆和换能器采用一体结构．在对电机的工作原理进行分析的基础上,利用ANSYS软件完成了电机的设计和仿真,实现了两个振动模态的特征频率简并,并采用多普勒激光测振仪对样机进行了振动测试,测试结果与仿真结果基本一致．样机的机械输出特性测试表明,样机的最大转速为268r／rain,最大输出力矩为1．1N·m．     

Effect of thickness of friction material on contact state of ultrasonic motor

Performances of ultrasonic motor (USM) considerably depend on contact state between stator and rotor.Based on an electric contact method,the effects of thickness of single homogeneous friction material...