行波型超声电机速度测控系统的研究

研制了一种行波超声电机速度的计算机测试控制系统。实验结果表明，该控制系统可以准确测试本中心研制的φ45mm压电行波型超声电机的启动关断性能，并解决了压电行波型电机由于长时间运转发热产生谐振频率漂移导致电机转速下降的问题，能进行频率跟踪，从而保持电机转速的稳定。     

宏微压电驱动器的电源设计与试验

针对超声电机与压电微驱动器对驱动电源的要求,设计出一种既能驱动超声电机又能驱动压电微驱动器的驱动电源,该驱动电源由可调变压器、半桥模块及以高性能数字信号处理(DSP)芯片TMS320F28335为核心的控制器组成。该电源驱动超声电机时,电源输出相位差、频率均较大范围连续可调的二相超声频率交流电;驱动压电驱动器时,电源输出较大范围连续可调的直流电。对行波型旋转超声电机及钹型压电驱动器的系列驱动试验表明该电源能同时满足超声电机和压电驱动器的驱动要求。     

真空度对环形行波超声马达驱动特性的影响

超声马达是一种适合于真空环境中工作的理想驱动器,但其在真空下的特性研究较少。利用真空试验机和超声马达特性模拟实验台,分别在常压、低真空和高真空下测试了无磁型和普通型环形行波超声马达的转速和转矩特性。结果表明,两台超声马达的转速和转矩均随环境压强减小而减小;在真空下,普通型超声马达的负载特性较常态下差,无磁型超声马达负载特性受真空度影响较小,且优于普通型超声马达的负载特性。运用声悬浮和摩擦学理论初步分析了产生此现象的原因。     

新型锥壳形旋转超声电机的研究

该文提出了一种新型锥壳形旋转行波超声电机,该锥壳形超声电机振子的三阶弯曲振动模态可以将面内、外弯曲振动结合起来,实现新型振动模式的行波驱动。利用有限元软件确定了振子结构尺寸、三阶弯曲振型及频率并制作了原理样机,对原理样机振动特性及输出性能进行了测试。测试结果表明,当激励电压峰峰值为240 V,谐振频率为27.53 kHz时,空载时超声电机最高转速为85.8 r/min,堵转力矩为441 mN·mm。     

压电叠堆驱动式超声电机设计

该文研究了拟发挥压电叠堆大输出力的特点,并提出了一种压电叠堆驱动的超声电机。电机定子由压电叠堆与金属弹性体结构组成,定子在交变激励信号下产生行波振动,并通过摩擦耦合驱动转子旋转输出。该文制作了样机,并搭建了实验平台。测试结果表明,电机转速与驱动电压呈正相关关系。当驱动电压峰-峰值为310 V时,电机最大输出转速为42.55 r/min,输出扭矩为0.8 N·m。     

基于DDS的超声电机驱动电源

传统的行波超声电机驱动电源通常只能固定相位差调频率或固定频率调相位差，不能全面的满足行波超声电机控制的要求。文章提出了一种新的方案，这种新的超声电机驱动电源，能产生两相可调频率，可调相位差及幅度的正弦信号。运用作者新的方案，解决了以往超声电机驱动电源只能调电压和调频率的缺点，而同时运用三种手段对超声电机进行调整，使各种型号的超声电机都能调整到一个良好的工作状态，从而提供对超声电机进行精确控制的基础。     

机器人的超声电机驱动及其控制研究

研究了超声电机在机器人中应用的可行性，探讨了行波超声电机（USM）的调速机理和调相伺服特性；引入了调相驱动的实现方法。针对超声电机驱动特点，在机器人动力学分析基础上，研究了动力学模型的线性化和解耦问题，提出了PD控制与前馈补偿相结合的机器人位置的控制方法。     

行波超声电机移动系统的动态研究

在仿真的基础上优化设计行波超声电机驱动系统，满足控制系统对高频驱动信号的变频、变压、变相位差的要求，利用驱动逆变电路的拓扑结构实现柔性控制以解决超声电机的驱动问题如电机结构的不平衡、两相逆变驱动电路的不平衡所造成的行波质量问题，在系统行波形成层面上控制振动参量，使驱动系统在一定范围内满足电机动态控制的要求。     

小型同步发电机组电压转速综合控制器设计

电力系统的稳定性主要取决于电机组转速和电压的响应特性,转速和电压相互作用对两者进行综合控制非常必要。为进一步提高小型同步发电机组的综合自动化水平,提出了一种集机组保护、励磁控制、调速控制、并网控制、温度巡检等功能于一体的小型同步发电机组电压转速综合控制器。该控制器以MSP430F2274为主处理器,CPLD为辅助控制器,使整个综合控制器具有功耗低、灵活可靠、适应性强的特点。     

旋转行波超声电机最优预压力的研究

为提升旋转行波超声电机输出性能,研究其在不同负载下的最优预压力,针对TRUM-70H超声电机进行了理论计算和实验验证。建立超声电机动力学模型,分析了预压力对超声电机机械特性的影响;以TRUM-70H超声电机为对象,分析其最优预压力与负载力矩间的关系;搭建超声电机多功能测试平台,验证理论推导结果,并指出误差存在的原因;根据研究结论,提出超声电机装配时应根据负载选用预压力。结果表明,预压力和负载力矩对超声电机转速的影响存在耦合关系;在超声电机有效工作范围内,最优预压力值与负载力矩近似呈线性正相关;装配时根据实际负载需求设定超声电机预压力,可提高其输出效率。     

Adjustable speed control of ultrasonic motors by adaptive control

The driving principle of the ultrasonic motor (USM) is different from those of the electro-magnetic type motors. Some mathematical models for the USM have been reported; however, these models are very complex to apply for speed control of the USM. Therefore, the speed controllers have been designed using PI controllers or fuzzy controllers and it is necessary to develop a simple and convenient mathematical model for the USM in order to achieve a high-performance speed control. In this paper, a mathematical model for the USM is proposed which is simple and useful for speed control. The speed controller is designed based on the model using adaptive control theory. Adaptive control is attractive for control of the USM because the speed characteristics of the USM vary with drive conditions. The application of this control scheme to speed control for the USM is attempted first. The effectiveness of proposed control is demonstrated by experimental     

Fuzzy adaptive model-following position control for ultrasonicmotor

A fuzzy adaptive model following mechanism for the position control of a traveling-wave-type ultrasonic motor (USM) is described in this study. Since the dynamic characteristics of the USM are difficult to obtain and the motor parameters are time varying, fuzzy adaptive control is applied to design the position controller of the USM for high-performance applications. The driving circuit for the USM, which is composed of a high-frequency boost DC-DC chopper, a two-phase series-loaded resonant inverter and an inner speed loop, is built first. Next, the control algorithm for fuzzy adaptive control is discussed. Then, a simple linear position control loop is designed and augmented by the model-following error-driven fuzzy adaptive mechanism to reduce the influence of parameter variations. The effectiveness of the proposed controller is demonstrated by some experimental results     

Speed control of ultrasonic motors using neural network

The ultrasonic motor (USM) is a newly developed motor, and it has excellent performance and many useful features, therefore, it has been expected to be of practical use. However, the driving principle of USM is different from that of other electromagnetic-type motors, and the mathematical model is complex to apply to motor control. Furthermore, the speed characteristics of the motor have heavy nonlinearity and vary with driving conditions. Hence, the precise speed control of USM is generally difficult. This paper proposes a new speed-control scheme for USM using a neural network. The proposed controller can approximate the nonlinear input-output mappings of the motor using a neural network and can compensate the characteristic variations by on-line learning using the error backpropagation algorithm. Then, the trained network finally makes an inverse model of the motor. The usefulness and validity of the proposed control scheme are examined in experiments     

A fuzzy neural network controller for parallel-resonant ultrasonicmotor drive

A newly designed driving circuit for the traveling-wave-type ultrasonic motor (USM), which consists of a push-pull DC-DC power converter and a current-source two-phase parallel-resonant inverter, is presented in this study. Moreover, since the dynamic characteristics of the USM are difficult to obtain and the motor parameters are time varying, a fuzzy neural network (NN) controller is proposed to control the USM drive system. In the proposed controller, a fuzzy model-following controller is implemented to control the rotor position of the USM, and an online trained NN with variable learning rates is implemented to tune the output scaling factor of the fuzzy controller. To guarantee the convergence of tracking error, analytical methods based on a discrete-type Lyapunov function are proposed to determine the desired variable learning rates. From the experimental results, accurate tracking response can be obtained by the proposed controller, and the influences of parameter variations and external disturbances on the USM drive also can be reduced effectively     

Rotary ultrasonic motor driven by a disk-shaped ultrasonic actuator

A rotary ultrasonic motor, including a disk-shaped ultrasonic actuator and a rotor, is developed, and the characteristics of the motor, including speeds, torques, output powers, and efficiencies, against various preload forces, voltages, and frequencies are investigated. The actuator is developed on a thin piezoelectric buzzer with three fixed screws and driven by a single-phase electrical power source. Here, the buzzer is composed of a nickel-alloy disk and a piezoceramic disk, and the screws are individually arranged at 90/spl deg/, 120/spl deg/, and 150/spl deg/ arc locations on the nickel-alloy disk. An optimal driving point of the actuator for driving the rotor in both clockwise (CW) and counterclockwise (CCW) directions is located at a point on the 90/spl deg/ arc edge region, and the CW and CCW directions are controlled by the frequency of the electrical power source. In doing so, the principle, construction, and driving mechanism of the actuator are first expressed. Then, the principle is verified according to vibration mode analysis with ANSYS simulation. The ANSYS simulation concerns the numerical model, structure, and mesh analysis as well. Moreover, a driving and measuring system, including an ac power supply system and a system that measures speed and twist forces, is constructed to evaluate the performance of the actuator and motor.     

一种基于虚拟仪器的超声电机通用电源

介绍了一种用于超声电机的多频、宽带、具有自恢复保护电路的通用驱动电源.该电源采用高频高压功率放大器,可输出两路峰-峰值200 V的电压,频率可高达300 kHz;采用LabVIEW虚拟仪器技术,输出频率、幅值、相位都可调的正弦波、方波、三角波等波形;与传感器结合,该电源易于构成控制电路.     

一种转子位置传感器无刷直流电机速度检测方法

本文提出了一种利用转子位置传感器发出的信号测量无刷直流电机（BLDC）转速的方法,并设计了相应的转动方向测定电路和数字PI速度控制器模块。通过利用比例积分控制器计算半个转动周期内的两次连续测量值,结合提出的转动方向测定电路和数字PI速度控制器,可以得出具有双倍测量频率的转子转动周期的准确值。最后将提出的方法在FPGA平台进行了实现,并与真实数据的对比表明,该算法在无换向器直流电机上可以获得具有高精度及高频率的速度测量值（每转动1周至少测量6次）。     

Fuzzy neural networks for identification and control of ultrasonicmotor drive with LLCC resonant technique

This paper demonstrates the applications of fuzzy neural networks (FNNs) in the identification and control of the ultrasonic motor (USM). First, the USM is derived by a newly designed high-frequency two-phase voltage-source inverter using LLCC resonant technique. Then, two FNNs with varied learning rates are proposed to control the rotor position of the USM. The USM drive system is identified by a fuzzy neural network identifier (FNNI) to provide the sensitivity information of the drive system to a fuzzy neural network controller (FNNC). A backpropagation algorithm is used to train both the FNNI and FNNC on-line. Moreover, to guarantee the convergence of identification and tracking errors, analytical methods based on a discrete-type Lyapunov function are proposed to determine the varied learning rates of the FNNs. In addition, the effectiveness of the FNN-controlled USM drive system is demonstrated by experimental results. Accurate tracking response can be obtained due to the powerful on-line learning capability of the FNNs. Furthermore, the influence of parameter variations and external disturbances on the USM drive system can be reduced effectively     

Control of a 2-DOF ultrasonic piezomotor stage for grommet insertion

The treatment of a common disease called “Otitis Media with Effusion (OME)” involves the surgeon inserting a grommet in the eardrum to bypass the Eustachian tube for draining fluid when medication fails. In this paper, a novel device for myringotomy and grommet insertion is first designed and introduced. Due to the advantages of high precision and fast response, a 2-DOF ultrasonic piezomotor (USM) stage is chosen to provide the motion sequences of the device, especially a precise path tracking during the grommet insertion. This paper briefly presents the mechanical design of the device and the configuration and control of the 2-DOF USM stage. The model of the USM consisting of a linear and nonlinear term is built. A PID controller is used as the main controller and tuned with the help of LQR technique. Since there are nonlinear dynamics caused by friction and hysteresis existing in the system, a nonlinear compensation including a sign function and sliding mode control is designed to reject the nonlinearity. Moreover, a decoupling controller is designed to eliminate the coupling effects between the two USM stages. The experimental results show that the LQR-assisted PID controller with compensation can achieve very good system performance and the decoupling controller can further improve the performance.