Ultrasonic motors: Their models, drives, controls and applications

In the last decades piezoelectrically driven ultrasonic motors have become alternative actuators to the conventional electromagnetic motors especially for precise and accurate servo positioning applications. Different types of ultrasonic motors have been constructed and manufactured. Several drive systems have been designed, implemented and proposed for these motors. A variety of control techniques have been applied to them. The research given in this study covers bases of the ultrasonic motors. Theoretical background, modeling, drive systems, control techniques and applications of the ultrasonic motors have been introduced. Firstly, the general overview has been given. Then, modeling studies focused on performance estimation and analysis of ultrasonic motors have been examined. Afterwards, drive systems and control techniques of ultrasonic motors have been investigated. Furthermore, an example drive and control system has been presented. This drive system has been designed as to be controlled digitally. In addition, the important industrial and research applications of these motors have been included. The presented study has been arranged as a review of ultrasonic motors. The important points of specifications, models, drive systems and control methods of the ultrasonic motors have been emphasized.     

Digital control for brush DC motor

In home appliances applications the brush DC motor, driven by a chopper, can be controlled by a standard microcontroller. However people often consider the microcontrollers as not suitable for the power environment because of their limited computing speed or noise immunity problems. This paper shows how a cost effective digital motor drive can be designed by combining a chopper and an 8 bits microcontroller: the speed is simply controlled through direct voltage compensation and motor power limitation. The microcontroller implements both motor control and interface functions of the application: it replaces the analog circuits of the conventional motor control. Performances and practical results are given for a 300 W/12000 RPM motor drive     

异步电动机定子磁链与电磁转矩的逆系统解耦控制方法

为了实现脉宽调制电压源型逆变器供电的异步电动机调速系统定子磁链和电磁转矩的动态解耦控制，基于逆系统理论提出了一种新型的解耦控制策略。根据异步电动机调速系统的动态数学模型，证明了其逆系统的存在性，在此基础上得到了逆系统的输入输出方程。把得到的逆系统和异步电动机调速系统相级联，从而将多变量、非线性、强耦合的控制对象解耦成了两个一阶线性子系统，分别称为转矩子系统和磁链子系统，利用线性控制理论对各个调节器进行了设计，实现了定子磁链和电磁转矩对各自参考值的全局渐进跟踪。使用Matlab软件进行了仿真实验，实验结果验证了控制方案的可行性。     

Experimental investigation of input–output characteristics of a travelling-wave ultrasonic motor

Speed, position and load characteristics of the ultrasonic motor is considerably influenced from the input characteristics such as driving frequency, magnitude and phase difference of phase voltages. Input and output characteristics of a traveling-wave ultrasonic motor have been investigated from the experimental point of view in the present study. For this aim, a half-bridge serial-resonance inverter based drive system has been designed and then implemented. The inverter is featured with pulse width modulation and pulse frequency modulation techniques. The frequency, amplitude and phase angle of two-phase sinusoidal output of the driver has been designed to be changed for the control purpose. Then the measuring circuits and tools have been set up to obtain required measurements. Input characteristics such as duty ratio of control signal-dc reference voltage, dc reference voltage-driving frequency and output characteristics such as driving frequency-rotor speed, driving frequency-feedback voltage, phase voltage-rotor speed are obtained from the experiments. Also load characteristics are studied with experiments. Afterwards these characteristics are discussed in details. This study gives a systematical experimental approach in order to demonstrate operating and control principles and characteristics of the travelling-wave ultrasonic motor.     

基于DSP的新颖无刷直流电机控制器设计

利用DSP2812设计了一个无位置传感器电机控制系统,该系统利用三相四开关电路对无刷直流电机(Brushless DC Motor,简称BLDCM)进行驱动,采用了新颖的无位置传感器控制方法和脉宽调制(PWM)方法.最后通过分析和试验证明了该系统的可行性.     

Quick and precise position control of ultrasonic motor using hybrid control

The ultrasonic motor has an excellent level of performance and many useful features, including high torque, low speed, compactness in size, and absence of electromagnetic interference. This motor has an especially large holding torque and a high response characteristic, making it ideal for use as a servomotor. The drive principle of the ultrasonic motor is, however, different from that of electromagnetic motors and its mathematical model has not been developed yet. Its speed characteristics, moreover, vary with the driving conditions. Consequently, it is difficult to control the ultrasonic motor while maintaining performance. In this paper, a position control scheme using adaptive control is proposed. The utility and validity of the proposed control scheme is tested in experiment.     

QUICK AND PRECISE POSITION CONTROL OF ULTRASONIC MOTORS WITH TWO CONTROL INPUTS

ABSTRACT

Ultrasonic motor (USM) has an excellent performance and many useful features. Since this motor is superior in holding torque and high response characteristic, it has been expected to use as position servomotor for small motors.

There have been reported some mathematical models of the ultrasonic motor. however, these models are too complex to apply for control of the motor. Therefore position controllers based on PI control or fuzzy control have been proposed in recent years. It is difficult to control the ultrasonic motor with high-performance using such controllers, thus simple and convenient mathematical model is necessary for precise control.

This paper presents a new position control scheme of ultrasonic motor, it consists of a PI controller and an adaptive controller which compensates the speed characteristic variations with online parameter identification. Moreover, this system controls both driving frequency and phase difference in order to achieve a quick and precise position control. The effectiveness of proposed control.scheme is demonstrated by experiments.     

A Switching Flux-linkage Reference-based Sensorless Method for Switched Reluctance Motor Drives

A switching flux reference estimation based method for sensorless control of switched reluctance motors is proposed in this article. The basic idea of the method is to estimate switching-on and switching-off flux linkage references from the giving switching angles range and measured phase current. Real-time comparing the estimated flux linkage with estimated switching flux references, the driving signals can be obtained for sensorless control and rotor speed estimation. For closed-loop control, switching-off angle is fixed for speed estimation, and switching-on angle is regulated by the speed deviation proportional-integrator controller. The process to estimate the switching flux references is greatly simplified compared with conventional flux/current methods; it is easily implemented and is suitable for low-cost industry applications. To verify the proposed method, experiments were conducted on a 1-kW, 3-phase 12/8 switched reluctance motor. Experimental results show that speed variable performance of the sensorless drive is comparable with that of position sensors.     

基于MACH软件三维雕刻机控制系统设计与实现

以MACH软件和PC为控制平台,通过接口及步进电机驱动电路,输出驱动脉冲,控制小型雕刻机三轴联动。讨论了雕刻机接口电路、可关断PWM直流电机调速电路、基于TB6560步进电机驱动电路设计,并给出部分设计电路及解释。控制系统在雕刻文字和图形的实际应用中,取得了良好效果。     

Speed tracking servo control system incorporatingtraveling-wave-type ultrasonic motor and feasible evaluations

A variety of ultrasonic motors (USMs) have attracted special interest as a new type of actuator in servo motion control systems. For practical applications, the speed servo control system incorporating the ultrasonic motor developed in Japan has some special unique features. However, this system has several significant problems, such as the inherent speed ripple characteristics, the speed regulation characteristics under the condition of applied disturbance load torque, and the speed tracking characteristics. In order to solve these practical problems, some control schemes of ultrasonic-actuated motor systems have been proposed and discussed theoretically, which include fuzzy reasoning control, adaptive control, repetitive learning control, and neural-network-based learning control. However, it is considered that these control strategies mentioned above have not been sufficiently substantiated from a feasible experimental point of view. This paper presents a newly proposed precise speed tracking servo control system using the compact traveling-wave-type ultrasonic motor. Its proposed control scheme is composed of both the driving frequency control loop with the variable-gain strategy and the applied voltage control loop with the speed ripple reduction strategy of the USM. The improved speed characteristics realized by this proposed control system are demonstrated and evaluated in experiments     

Neuro-fuzzy speed tracking control of traveling-wave ultrasonic motor drives using direct pulsewidth modulation

The traveling-wave ultrasonic motor (TWUM) drive offers many distinct advantages but suffers from severe system nonlinearities and parameter variations, especially during speed control. This paper presents a new speed tracking control system for the TWUM drive, which newly incorporates neuro-fuzzy control and direct pulsewidth modulation to solve the problem of nonlinearities and variations. The proposed control system is digitally implemented by a low-cost digital-signal-processor-based microcontroller, hence reducing the system hardware size and cost. Experimental results confirm that the proposed speed tracking controller can offer good steady-state and transient performance.     

Position control of the induction motor using a passivity-basedcontroller

Most position tracking applications employ either DC or permanent-magnet motors. In this paper, an induction motor drive for position control applications is proposed. Such a drive adopts a passivity-based controller which mainly differs from the others because its formulation emphasizes system energy properties and behavior. The controller has simple equations and good robustness without using complex flux observers and the exact knowledge of the motor parameters, as well. The proposed drive has been practically implemented, achieving satisfactory results     

感应电机非线性输出反馈控制变频调速系统

针对以定子电压为控制量的交流感应电机调速系统存在的系统结构复杂、实时计算量大的缺点,提出了一种感应电机的非线性输出反馈控制变频调速方法。该方法依据感应电机的降阶模型,采用非线性输出反馈控制技术设计外环转速与磁链控制器,以滞环比较器作为内环电流跟踪控制器,直接产生PWM信号控制电压源逆变器,驱动感应电机运行,实现了对光滑转速参考信号的渐近跟踪。仿真结果表明该系统不仅具有快速的动态响应性能,而且对负载扰动具有较强的鲁棒性。     

Novel Two-Switch-Based Switched Reluctance Motor Drive for Low-Cost High-Volume Applications

This paper presents a low-cost energy-efficient variable-speed drive for high-volume applications, such as home appliances, fans, and hand tools. A new low-cost power converter is proposed, and the drive system is realized using a two-phase switched reluctance motor and the proposed converter. The motor is capable of self-starting at any rotor position and four-quadrant operation. The converter is unique in that it has two capacitors for the energization of each phase and uses the main phase winding as energy storage for the secondary capacitor C2. The converter employs a single-switch-per-phase configuration, hence requiring only two controllable switching devices in total. The converter is inherently suited for two-phase motors having asymmetric stator phases to realize self-starting and speed reversal. Simple starting and C2 voltage control schemes are presented. This paper describes the analysis, modeling, control algorithm, and design considerations for a prototype drive system. Experimental verification and correlation with simulation results are presented. The proposed drive system offers a low-cost brushless variable-speed drive that is a potential alternative for conventional brush-commutator motors in high-volume applications.     

Textile Applications of Adjustable-Frequency Drives with Digital Ratio Control

The application of digital techniques to program and to process the input signals to adjustable-frequency inverters for the control of rugged ac motors is becoming widespread. It was perhaps inevitable that digital signal control would eventually be combined with the inherently digital adjustable-frequency power inverter to produce systems having high overall line speed accuracy, adjustable ``digital gearing' between sections, locked-in-step acceleration from creep to run speed, and in-train digital jogging. A short introduction to adjustable-frequency motor control is given, and the use of digital techniques for controlling adjustable-frequency inverters to produce digital speed systems is described. Early applications of the first solid-state inverters to synthetic fiber spinning and their continued use is described. Specific current applications of digitally controlled adjustable-frequency speed systems are discussed, and potential applications that demonstrate how the capabilities of such systems can be used to provide economic solutions to many textile industry drive problems are reviewed.     

INVESTIGATIONS ON DYNAMIC BEHAVIOR OF PERMANENT MAGNET BRUSHLESS DC MOTOR DRIVE

ABSTRACT

Permanent magnet brushless dc (PMBLDC) motors are increasingly being used in a wide range of applications such as machine tools, robotics and high precision servo applications. A comprehensive analysis which includes modeling and simulation of PMBLDC motor drive is presented in this paper. A mathematical model of the drive is developed with a view to studying the transient response of current controlled voltage source inverter (VSI) fed PMBLDC motor. The drive system consists of discrete PID(Proportional, integral plus derivative) speed controller, the reference current generator, the position sensor, an inverter and the motor. Each part of the drive system is modeled separately and then integrated to study the dynamic behavior of the drive system. The study also examines the effectiveness of the drive system during starting, load perturbation, speed reversal and dc link voltage fluctuation.     

录像机用伺服电机驱动电路的设计

录像机用伺服电机驱动电路是录像机伺服系统设计中的重要部分.介绍了录像机伺服系统中鼓电机驱动电路、主导轴电机驱动电路设计中使用的专用IC的型号、主要技术特点及应用方法,为录像机伺服系统中电机驱动电路的设计提供了有价值的解决方案.     

Sensorless induction spindle motor drive using fuzzy neural network speed controller

A sensorless induction spindle motor drive using synchronous PWM and dead-time compensator with fuzzy neural network (FNN) speed controller is proposed in this study for advanced spindle motor applications. First, the operating principles of a new type synchronous PWM technique are described in detail. Then, a speed observer based on the model reference adaptive system (MRAS) theory is adopted to estimate the rotor speed. To increase the accuracy of the estimated speed, the speed estimation algorithm is implemented using a digital signal processor. Moreover, since the control characteristics and motor parameters for high speed operated induction spindle motor drive are time-varying, an FNN speed controller is developed to reduce the influence of parameter uncertainties and external disturbances. In addition, the FNN is trained on-line using a delta adaptation law. Finally, the performance of the proposed sensorless induction spindle motor drive system is demonstrated using some simulation and experimental results.     

基于FPGA的自动相机聚焦电机伺服控制系统集成电路(IC)设计与实现

采用现场可编程门阵列(FPGA)实现了自动相机聚焦(AF)镜头模块位置控制电机伺服控制系统集成电路(IC)的全数字控制设计。镜头模块位置控制驱动电机由具有数字伺服驱动的音圈电机(VCM)担任,数字伺服驱动包括数字伺服控制器、数字电流控制器和全桥DC-DC转换器,系统能为高性能、轻质量和超薄型的移动式自动相机的AF镜头模块位置控制提供完整的数字控制方案,使相机的AF镜头模块控制范围在30 ms内可以达到0.6 mm,控制分辨率小于5μm,驱动力峰值为30 mN,输出电流峰值为120 mA。     

Position sensorless control for ultrasonic motors based on input voltage information

This paper presents a method of position sensorless control of ultrasonic motors (USM). The position sensorless control method is useful for reducing the cost and size of drive system. The position estimation method is based on the input voltage information of the ultrasonic motor. The characteristic of input voltage versus rotor position is expressed by a quadratic function which is used to estimate a rotor position based on input voltage information. This estimation method, which uses only the drive voltage of the ultrasonic motor, is a very simple algorithm and shows good estimation ability. The parameters of the quadratic function are adjusted by using the recursive least squares method and are obtained on‐line. Since it can correspond to parameter change, the estimated rotor position shows good agreement with the measured rotor position against load torque and motor temperature changes. Sensorless position control is achieved by using the estimated rotor position instead of the measured rotor position. The validity of the proposed method is confirmed by experimental results. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(1): 57–64, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20626