Working Mechanism of a Kind of Non-resonant Linear Piezoelectric Motor with Flexible Driving End

A non-resonant piezoelectric linear motor with a flexible driving end,which has an extensive working frequency range and good operation stability,is studied theoretically and experimentally.Based on the microscopic vibration characteristics of the motor stator,the longitudinal vibration model is established for the whole motor system.According to the Coulomb friction model and the motor vibration model,the friction mechanism of the nonresonant piezoelectric linear motor is investigated by dynamical analysis of the whole motor system.Furthermore,the vibration characteristics and mechanical output characteristics of the stator are simulated and experimentally studied on the basis of the friction drive mechanism model.Finally,both the simulation and experimental results show that this kind of motor remain stable in the frequency domain from 2.2 kHz to 3.5 kHz and that when the pre-stress is 4 Nand the driving voltage is 90 V,the maximum velocity of the motor is above 4 mm/s and the maximum thrust is nearly 0.5 N.

Novel Linear Piezoelectric Motor for Precision Position Stage

Conventional servomotor and stepping motor face challenges in nanometer positioning stages due to the complex structure, motion transformation mechanism, and slow dynamic response, especially directly driven by linear motor. A new butterfly-shaped linear piezoelectric motor for linear motion is presented. A two-degree precision position stage driven by the proposed linear ultrasonic motor possesses a simple and compact configuration, which makes the system obtain shorter driving chain. Firstly, the working principle of the linear ultrasonic motor is analyzed. The oscillation orbits of two driving feet on the stator are produced successively by using the anti-symmetric and symmetric vibration modes of the piezoelectric composite structure, and the slider pressed on the driving feet can be propelled twice in only one vibration cycle. Then with the derivation of the dynamic equation of the piezoelectric actuator and transient response model, start-upstart-up and settling state characteristics of the proposed linear actuator is investigated theoretically and experimentally, and is applicable to evaluate step resolution of the precision platform driven by the actuator. Moreover the structure of the two-degree position stage system is described and a special precision displacement measurement system is built. Finally, the characteristics of the two-degree position stage are studied. In the closed-loop condition the positioning accuracy of plus or minus 〈0.5 μm is experimentally obtained for the stage propelled by the piezoelectric motor. A precision position stage based the proposed butterfly-shaped linear piezoelectric is theoretically and experimentally investigated.

Linear Piezoelectric Stepping Motor with Broad Operating Frequency

The existing resonant linear piezoelectric motors must operate with high working voltage in resonant condition,resulting in their narrow operating frequency range and poor running stability.Here,with the large displacement output characteristics of piezoelectric stacks,the trajectory at the drive foot of stator is firstly produced with two space quadrature piezoelectric actuators excited by sawtooth wave and square wave.Secondly,the friction drive principle of motor is used to analyze the working mechanisms of the continuous stepping motion.Finally,the motor prototype is designed and experiments are carried out.The experimental result shows that the motor can stably operate within the scope of 350 Hz to 750 Hz.When the excitation voltage is 30 Vand pre-load is 3Nor10 N,the lateral amplitude of the drive foot is approximately 4μm and the stable average interval ranges from3.1μm to 3.2μm with the error rate of 5%—7.5%.

Experiment on a Double-Foot Stepping Piezoelectric Linear Motor

A novel double-foot piezoelectric linear motor is proposed.The kinematic model of the motor under stepping motion is presented.The motor mainly consists of a stator with four piezoelectric stacks,a mover,a holding mechanism,and a preloading mechanism to achieve large stroke with high resolution.Finite element simulations are carried out to analyze the motion characteristics of the motor.A prototype is fabricated and a serial experiments are conducted to validate the feasibility of the motor principle.Experimental results indicate that the motor can move at a speed of 670.22μm/s with a driving frequency of 120 Hz and a voltage of 120 V.The resolution of the proposed motor is 3.6μm while the resolution of the single-step motion is 0.1μm.

Transient Response Model of Standing Wave Piezoelectric Linear Ultrasonic Motor

A transient response model for describing the starting and stopping characteristics of the standing wave piezoelectric linear ultrasonic motor was presented. Based on the contact dynamic model, the kinetic equation of the motor was derived. The starting and stopping characteristics of the standing wave piezoelectric linear ultrasonic motor according to different loads, contact stiffness and inertia mass were described and analyzed, respectively. To validate the transient response model, a standing wave piezoelectric linear ultrasonic motor based on in-plane modes was used to carry out the simulation and experimental study. The corresponding results showed that the simulation of the motor performances based on the proposed model agreed well with the experimental results. This model will helpful to improve the stepping characteristics and the control flexibility of the standing wave piezoelectric linear ultrasonic motor.

A Piezoelectric Friction-Inertial Linear Motor Based on Piezoelectric Single-Crystal Cymbal Displacement Amplification Mechanism

Piezoelectric friction-inertial motor is known for its promise for a long-range and high-resolution motion.The movement of the slider/rotor of the motor is achieved by stick-slip effect.We report a relaxor-based-ferroelectric-single-crystal cymbal actuator and a miniature piezoelectric friction-inertial linear motor(abbreviated as PFILM)fabricated with the cymbal actuator.The cymbal actuator is fabricated with a 10 mm diameter disk of 0.70Pb(Mg_(1/3)Nb_(2/3))O_3-0.30PbTiO_3 single crystal.The displacement of the cymbal actuator increases almost proportionally from 0to 23μm with driving voltage up to 500 V,and the minimal hysteresis is observed.The cymbalPFILM with 20 mm motion range works under driving voltage frequency of ca.100 Hz to ca.5kHz,the fastest speed is obtained with 3.5kHz and the no-load speed is 14mm/s and the maximum thrust force is 98 mN.Compared with a PFILM based on multilayer piezoelectric ceramic,the proposed motor has a larger stroke under DC/quasistatic input voltage in fine motion mode,but a smaller driving force in long-travel mode due to lower resonance frequency.

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.

A Study on the Mode Shape Piezoelectric Motor

In this paper, we try to use the coating of effective electrode surface and change the direction of polarization to design the mode shape piezoelectric motors of the first three modes. We also com-pare the gain of the mode shape piezoelectric motors with respect to the normal shape piezoelectric motor, including rotational speed, loading ability, torque, phase angle conversion and efficiency. According to the results of theoretical and simulation analysis, we have found that the gain of the mode shape piezoelectric stators are larger than the normal shape piezoelectric stator on average. According to the results of experiments, we found that the gain of the rotational speed, loading ability, torque, driving phase angle conversion and efficiency of the mode shape (MS1 - 3) piezoelectric motors are higher than the normal shape piezoelectric motor (NS) under driving condition of the second vibration mode. Also, the gain of the rotational speed and loading ability of the mode shape 2 (MS2) piezoelectric motor are higher than other shapes piezoelectric motors (NS, MS1 and MS3) under driving condition of the second vibration mode. The used maximum rotational speed of the mode shape 2 (MS2) piezoelectric motor is up to 946 rpm under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency, 0o driving phase angle and 13.0 gw net weight. The maximum loading ability and torque of the mode shape 2 (MS2) piezoelectric motor is respectively 451 gw and 0.91 mkgw-m under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency, 0o driving phase angle and 173 rpm rotational speed. And the gain of efficiency (output power) and maximum loading ability (torque) of the mode shape 2 (MS2) piezoelectric motor are respectively 2.28 and 1.54 with respect to the normal shape piezoelectric motor under conditions of 180 Vp-p driving voltage, 10.7 kHz driving frequency and 0o driving phase angle. According to the results of the experiments, we have finally found that the piezoelectric motors (NS and MS1 - 3) can be driven only by the second vibration mode because the stator can produce elliptical motion and allows the rotor to generate orientation rotation. However, the first vibration mode can allow the rotor to be rotated very fast but it can’t make the rotation of the rotor orientation. Furthermore, we also found that the rotor can’t rotate by the third vibration mode because its vibration energy is absorbed by the structure itself, so causing the rotor stagnation.

Power Supply of Macro-Micro Driven Linear Piezoelectric Motor

To investigate a novel macro and micro driven linear piezoelectric motor composed of an ultrasonic motor with macro movement and a piezoelectric actuator with micro movement,a digital signal processing(DSP)based macro and micro power supply is designed,which fits the new linear piezoelectric motor.The power supply comprises a control circuit,a voltage conversion circuit,an amplifier circuit,a half-bridge module,an optical isolatorsdrive circuit,etc,where the DSP of TMS320F28335 is used as the controller.When the linear piezoelectric motor working in a macro driven state,the power supply outputs alternating currents with high frequency and high voltage,which drives the linear piezoelectric motor dynamically at an ultrasonic frequency;while working in the micro driven state,the power supply outputs direct currents with high voltage,which drives the linear piezoelectric motor in micro driven statically.Here a prototype of the macro-micro power supply is designed.After a series of experiments on the power supply with and without loads,the results show that the power supply can drive and control the macro micro driven linear piezoelectric motor,and realizes quick and seamless switch between macro and micro drive.In addition,the power supply can drive and control the ultrasonic motor or piezoelectric ceramic micro actuator individually.The power supply achieves the multiple parameters of output signals adjustable simultaneously and exhibits good control characteristics.

A Study on the Linear Piezoelectric Motor of Mode Shape

In this paper, we want to make a new type linear piezoelectric motor by mode shape coating or effective electrode surface coating. The mode shape is derived from the mechanical boundary conditions of the linear piezoelectric motor. We only have access to the first three modes of formas, the effective electrode surface coating basis, as well as with the linear piezoelectric motor of normal shape do comparison. Next, we will inspect their gain or axial velocity through theoretical analysis, simulation and experiment. According to the results of the theoretical analysis, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much larger than the linear piezoelectric motors of normal shape. However, according to the results of simulation and experiments, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much greater than the linear piezoelectric motors of normal shape, which is about 1.2 to 1.4 times. The linear piezoelectric motor of mode shape 3 has the fastest axial velocity, which is about -48 mm/s and 48 mm/s under conditions of 180 Vp-p driving voltage, 21.2 kHz driving frequency (the third vibration modal), 25 gw loading and the position of loading or mass at x = 5 mm & 45 mm respectively. And its axial velocity is about 1.4 times the linear piezoelectric motor of normal shape under the same conditions. Overall, the mode shape coating helps to enhance the gain or axial velocity of the linear piezoelectric motor.

A Study on the Multiple Composite Piezoelectric Motor

In this study, we major discuss a multiple composite piezoelectric motor. It is made by the base, the multiple composite piezoelectric stator and the preload adjusting module. The multiple composite piezoelectric stator is composed of the base, the first actuating element, the second actuating element and stator. The first actuating element is composed of the longitudinal and the first bending vibration modules, in which the first bending vibration module includes the horizontal and vertical bending vibration modules. And the second actuating element or bending vibration modules, wherein the second actuating element also includes the horizontal and vertical bending vibration modules. In addition, the preload adjusting module includes the limiting element, spring, washer and nut. In order to obtain the best vibration modes of the multiple composite piezoelectric motor, we use the ANSYS code to simulate. And so as to get the better performance and efficiency relate to the previous similar type’s motor under the same driving conditions, we try to use different vibration modules or modes to drive the multiple composite piezoelectric motor, including the longitudinal, the first bending, the second bending and the multiple vibration modules or modes by experiments. According to the results of the simulations and experiments, we found that the multiple composite piezoelectric motor has better rotational speed, loading ability and conversion efficiency of direction relate to the previous similar type’s motor. Where the maximum rotational speed multiple composite piezoelectric motor is up to 600 rpm under conditions of 180 Vp-p driving voltage, 37.8 kHz driving frequency, 00 driving phase angle and 12.1 gw loading. And the maximum loading ability is 2500 gw under conditions of 180 Vp-p driving voltage, 37.8 kHz driving frequency, 00 driving phase angle and 6rpm rotational speed.

A Study on the Composite Type Piezoelectric Motor

This study is to explore a composite type piezoelectric motor. Its main structures include the piezoelectric stator, rotor, the preload adjusting module and shaft. Wherein the piezoelectric stator is made base, the composite type actuating element and stator formed. As the composite type actuating element is set by the axial vibration type actuating element, horizontal bending vibration type actuating element and vertical bending vibration type actuating element formed. The stator is an empty cylinder with a waist and tapered hole. In addition, the rotor is a kind of a hollow cone. It can be through the preload adjusting module to withstand the stator. As the preload adjusting module is set by the limit element, spring, washer and nut formed. While the shaft is a kind of cylinder with screw thread and stopper, it can pass through the piezoelectric stator, rotor and the preload adjusting module, making it a composite type piezoelectric motor. When we provide appropriate driving voltage, frequency, loading and phase angle to the piezoelectric stator, we can let the piezoelectric motor produces rapid rotation. Of course, we can also change through the driving phase angle, to change the direction of rotation of the piezoelectric motor. According to the experimental results, we found that its maximum speed and loading are 480 rpm and 2305 gw under conditions of 180 Vp-p, 35 kHz and 00 driving phase angle. Most importantly, we also found that the composite type piezoelectric motor has a very good conversion efficiency of the driving phase angle.

Novel Traveling Wave Sandwich Piezoelectric Transducer with Single Phase Drive:Theoretical Modeling,Experimental Validation,and Application Investigation

Most of traditional traveling wave piezoelectric transducers are driven by two phase different excitation signals,leading to a complex control system and seriously limiting their applications in industry.To overcome these issues,a novel traveling wave sandwich piezoelectric transducer with a single-phase drive is proposed in this study.Traveling waves are produced in two driving rings of the transducer while the longitudinal vibration is excited in its sandwich composite beam,due to the coupling property of the combined structure.This results in the production of elliptical motions in the two driving rings to achieve the drive function.An analytical model is firstly developed using the transfer matrix method to analyze the dynamic behavior of the proposed transducer.Its vibration characteristics are measured and compared with computational results to validate the effectiveness of the proposed analytical model.Besides,the driving concept of the transducer is investigated by computing the motion trajectory of surface points of the driving ring and the quality of traveling wave of the driving ring.Additionally,application example investigations on the driving effect of the proposed transducer are carried out by constructing and assembling a tracked mobile system.Experimental results indicated that 1)the assembled tracked mobile system moved in the driving frequency of 19410 Hz corresponding to its maximum mean velocity through frequency sensitivity experiments;2)motion characteristic and traction performance measurements of the system prototype presented its maximum mean velocity with 59 mm/s and its maximum stalling traction force with 1.65 N,at the excitation voltage of 500 V_(RMS).These experimental results demonstrate the feasibility of the proposed traveling wave sandwich piezoelectric transducer.

纵扭复合型超声电机定子的非线性动力学特性研究

纵扭复合型超声电机的非线性动力学特性是影响电机运行的稳定性和可靠性的重要因素。基于广义Hamilton能量变分原理、Rayleigh-Ritz假设模态法以及非线性压电本构关系,建立纵扭复合型超声电机定子的非线性动力学模型,采用四阶Runge-Kutta法和Lyapunov指数等方法仿真分析纵向激励下电机定子的非线性振动响应特性。结果表明:电机定子的固有模态频率和实验值误差仅为1.8%,证明了所建立的纵扭复合型超声电机定子的非线性动力学模型的准确性。超声电机具有频率漂移、振幅跳跃等非线性行为特性,而实际工作时通常将定子的共振频率(即λ=1处)作为工作激励频率,此时位于稳定的周期运动区域。通过数值仿真分析得到不同频率激励下系统的发展趋势,以及系统稳定与不稳定运动的参数匹配区间,可为开展纵扭复合型超声电机的非线性动力学特性研究提供参考。

面内驱动旋转超声电机的研究进展

超声电机利用压电陶瓷的逆压电效应和机械共振来获得其运动和力矩,具有响应快速、定位精度好、可直接驱动等诸多优点,在精密驱动、航空航天、生物医学等领域具有独特的应用优势和成功应用,已有成熟产品实现产业化。基于面内振动模态的微小型超声电机是目前相关研究最易于微小型化的一类,在微机电系统领域具有很好的应用潜力和空间。首先,介绍了超声电机的工作原理;其次,针对夹心式换能器定子结构和贴片式定子结构两种类型面内驱动旋转超声电机,从不同的结构形式、输出性能、应用研究方面归纳总结相关研究的新进展和新成果,比较分析了几种电机样机的主要性能;最后,指出需要深入研究和技术突破的几个问题。

同步辐射扫描透射X射线显微成像系统振动的闭环控制方法研究

上海同步辐射光源(Shanghai Synchrotron Radiation Facility,SSRF)扫描透射X射线显微成像(Scanning Transmission X-ray Microscopy,STXM)实验站是国内首个自主研制的STXM实验系统,目前该系统波带片聚焦直接成像分辨率达到15 nm,扫描相干衍射成像方法成像的分辨率达到7.32 nm。系统振动是影响其成像质量的主要因素。本文针对波带片和样品之间系统振动进行详情分析,并提出相应的抑制策略,旨在提升STXM系统的成像质量。采用激光干涉仪和现场可编程门阵列(Field Programmable GateArray,FPGA)技术,从软件层面开发了一种针对STXM中波带片和样品位置稳定性的闭环控制系统。该控制系统在最佳条件下可将STXM系统振动的均方根值(Root Mean Square,RMS)有效控制到4.833 nm,减少至原振动水平的约1/3,为STXM系统的成像质量进一步提升奠定了技术基础。

基于压电电机的光学稳像平台

结合压电电机响应快,定位精度高及控制性能好的特点,设计了一款基于压电电机的光学稳像运动平台。利用COMSOL对电机定子进行有限元仿真,分析了定子的工作原理及响应特性。通过实验测得电机的最佳工作频率及预压力,并分析了响应速度与激励电压、工作频率、预压力之间的关系。采用多种控制方法进行定位测试,利用PID加步进的复合控制模式,实现了误差250 nm内的较高精度定位控制。

A NEW CONTROL METHOD FOR ULTRASONIC MOTOR

A new method for the control of the speed of an ultrasonic motor and its implementation are proposed. The method is merely used by detecting the time when motor′s monitor signal reaches a non zero reference value than a zero one, the direction, in which the driving frequency of the motor should be shifted, can be promptly calculated. With the aid of a CPU and the phase locked frequency doubling technique, the motor can be steadily driven in a wide range of frequency and the optimum frequency can be captured rapidly and precisely. Experiment shows that the above method is available.

贴片式复合模态型直线超声电机的仿真与试验评价

为了实现结构紧凑、低电压驱动、大推力输出以及高精密定位等性能目标,该研究提出了一种贴片式复合模态型直线超声电机。该电机的定子结构采用贴片式压电陶瓷作为激励单元,通过同时激发定子的B 12和B 2两种弯曲振动模态,实现了两个驱动足处的交替椭圆轨迹运动,借此利用摩擦力驱动动子进行直线运动。首先,应用有限元仿真软件COMSOL对定子的模态和频率响应进行了仿真分析。仿真结果表明,定子上两驱动足处能够实现预期的椭圆运动轨迹。随后,加工了电机的定子并进行了导纳测试,验证了有限元仿真的正确性。最后,制作了超声电机的原理样机,并通过一系列试验评估了其输出性能。试验结果表明:在100 Vpp电压和66.58 kHz频率条件下,电机的最大空载速度和最大推力分别达到了82.9 mm/s和0.52 N;在1.2 N的预压力作用下,电机的启动电压死区为12 Vpp;在周期为20的正弦波电压信号下,电机实现了2.1μm的步进位移。该研究为贴片式复合模态型直线超声电机的设计和应用提供了重要的理论与试验依据。

尺蠖式压电陶瓷电机的双模式驱动器开发与研究

尺蠖式压电陶瓷电机具有小尺寸,长行程,纳米级定位和大推力的特性,被广泛应用于集成电路装备和精密运动平台中。然而目前受其驱动器约束,难以实现长行程运动时高精度定位、位移可控和速度可控,因而无法应用到具有高推力、高速度和长行程纳米级精度定位的集成电路7 nm工艺IC芯片检测装备中。提出并开发了一种双模式驱动器,基于电荷效应和应力效应原理分别建立了位移-电压和速度-频率的控制模型。采用滑模控制的方法解决了在双模式驱动器大电压输出时的纹波问题,提高了尺蠖式压电陶瓷电机输出的位移分辨率。通过实验对双模式驱动器进行了硬件性能和控制模式验证,同时验证了尺蠖式压电陶瓷电机的运动特性。