压电陶瓷振荡器

本文叙述用压电陶瓷滤波器制作的振荡器。根据实测的压电陶瓷三端滤波器幅频特性和相频特性,且根据反馈振荡器起振条件和平衡条件,若用压电陶瓷三端滤波器作为反馈振荡器中的反馈网络,则反馈振荡器中放大器的输入信号与输出信号的相位关系可以是同相,也可以相差180°。环境温度在24～55℃变化时,实测压电陶瓷振荡器的频率稳定度约在10~(-5)/℃数量级,电源电压在11.5～12.5V变化时,其频率稳定度均为10~(-4)/V数量级,其性能优于RC振荡器和LC振荡器,且电路简单,体积小,调试方便,失真小,用于产生单一频率的低频信号是极其可取的方案。     

Stick-Slip Tower-Shaped Piezoelectric Actuator

Since stick-slip actuators present the advantage of allowing long displacements(several centimeters or even more)at a high speed with an ultra high resolution(5nm),a new type of stick-slip piezoelectric actuator is proposed to attain sub-nanometer positioning accuracy.The actuator is composed of a slider and a tower-shaped stator using forced bending vibration in y-z plane to generate tangential vibration on the top of the driving foot.When excited by the sawtooth input voltage,driving foot of the stator is able to generate a tangential asymmetrical vibration on the top,and the slider is thus pushed to move.A prototype and its testing equipment are fabricated and described.Following that,the testing of vibration mode and mechanical characteristics as well as stepping characteristics are conducted.Experimental results show that under the condition that the sawtooth input voltage is400VP-Pand the pre-pressure is 6N.Velocity of the actuator reaches its maximum 1.2mm/s at the frequency of 8000 Hz and drops to its minimum 35nm/s at the frequency of 1Hz.When the excitation signal is the single-phase sawtooth stepping signal,the tower-shaped actuator can directionally move forward or backward step by step.And when excited by the sawtooth stepping signal with 1Hz and 300VP-Pduring 1cycle(200ms),the actuator has a minimum stepping distance of 22 nm.     

多片压电双晶片并联驱动器的设计

针对微型无人机在受到外界干扰时通过自适应控制来实现飞行的稳定性设计了一种多片压电双晶片并联驱动的新型驱动器.用功率放大器和频谱分析仪分别对驱动器的在空载和带栽情况下的静态特性和动态特性进 行了测试,分析比较了在不同负载下单片压电双晶片和双片压电双晶片组成的驱动器的驱动能力,测得了双片 压电双晶片并联驱动器的输出位移和驱动电压之问的传递函数.实验结果表明:该驱动器不仅可以实现位移放 大,而且可以通过多片压电双晶片并联补偿驱动器的输出力,为设计新型压电双晶片驱动器提供了新的思路,同 时为压电双晶片驱动器的自适应控制提供了参考.     

压电智能结构的实验研究

在复合材料表层铺设压电元件，利用压电元件能够实现力学量和电学量之间相互转化的独特性能，可将其用作传感器和驱动器，赋予材料和结构传感及动作的能力。本研究的压电材料采用锆钛酸铅压电陶瓷，基体材料采用玻璃纤维－环氧树脂复合材料，与外部信号采集和控制系统结合，构成了智能结构实验系统。本文对这一系统的损伤诊断和损伤主动控制功能进行了实验研究。该结构一方面可对冲击、过载等可能造成损伤的原因进行监测，并诊断裂缝、连接松动等损伤的产生和位置，另一方面还可自适应地驱动结构中的压电驱动器，改善结构应力状态，防止损伤的扩展。     

Simulation Analysis and Experiment on Piezoelectric Cantilever Vibrator

Piezoelectric cantilever bimorph vibrator is the core component of piezoelectric inertial actuators.Piezoelectric cantilever bimorph vibrator with lumped mass at the end is studied,and a dynamic model is constructed by the proposed method of transforming symmetric electrical signal excitation to equivalent harmonic force excitation.Combining the theory and test,the single-degree-of-freedom damp vibration system consisting of the vibrator is analyzed and the full response is provided.Dynamical system modeling and simulation are conducted by software Matlab/Simulink.The output response of deflection,velocity,acceleration,driving force are solved using the input signal of equivalent harmonic force.Based on the data of theory,simulation and experiments,the deflection of vibrator is analyzed and compared under the excitation of sine wave signal.Result shows that the dynamic deflection results of vibrator from theory,simulation and experiments agree well with each other.The proposed modeling and analysis approaches of the single-degree-of-freedom damp vibration system consisting of the vibrator,have some reference significance for further research of piezoelectric inertial actuators.     

横观各向同性压电矩形薄板的非线性振动

由于压电材料在航空航天轻形结构动力控制中的广泛应用，压电结构的非线性机理成为工程界急需解决的问题。为了拓广压电结构的理论基础，本文对于横观各向同性压电矩形薄板，给出了大挠度条件下的应变位移关系，利用Hamilton原理导出了压电矩形簿板的非线性振动方程，并用双重Fourier级数展开和Galerkin方法获得四边简支压电矩开薄板非线性自由振动的解析解，分析了材料参数和几何参数对振动特性的影响。     

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.     

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%.     

自调谐宽频带压电振动发电机的改进

压电振动发电机使无线传感器网络实现能量自给。然而,压电振动发电机仅在与外界振源共振时才得到较高的能量转换效率。为此提出一种改进的自适应频率调谐的压电振动发电机,利用同步开关刚度控制电路改变结构固有频率,使之趋近于激励频率,是一种控制简单、控制效果好的半主动控制方法。在建立系统机电模型基础上,推导了开关控制电路相关公式,并根据系统特点运用基于梯度法的模型参考自适应控制方法。实验结果与理论分析结果一致,改变调频系数,结构固有频率相对变化率可以达到5.1%,且在一定频率调节范围内可以实现自供能。     

Test on an Optimized Cylindrical Non-contact Piezoelectric Actuator

An optimization design for the cylindrical non-contact piezoelectric actuator is presented after analyzing the acoustic radiation pressure and acoustic viscous force.By adding the specific microstructure on the rotor to alter the near-field sound effect and maximize the use of high intensity acoustic field induced by the stator to drive the rotor,the rotor speed is increased.The finite element analysis of the acoustic field induced by a variety of rotors with different structures is conducted,A prototype is manufactured,the speed-test system for the actuator is built,and the driving characteristics are measured.The results suggest that the rotation speed of the rotor can reach 4 167r/min,which demonstrates that the driving characteristics of cylindrical non-contact piezoelectric actuator are successfully improved using the optimization method proposed.     

Release Method of Microobjects Based on Piezoelectric Vibration

A release method of microobjects is presented based on the piezoelectric vibration.To achieve an effective release,the piezoelectric vibration is added to overcome adhesion force happened in the microoperation.This technique employs inertia force to overcome adhesion force,thereby achieving 90%repeatability with a releasing accuracy of 4± 0.5μm,which was experimentally quantified through the manipulation of 20—80μm polystyrene spheres under an optical microscope.Experimental results confirmed that this adhesion control technique was independent of substrate.Theoretical analyses were conducted to understand the releasing mechanism.Therefore,the micromanipulation system proved to be effective for active releasing of micromanipulation.A novel gripper structure with triple finger is devised.In the design,three cantilevers are considered as the end effectors of the fingers,driven by piezoelectric ceramic transducer(PZT).Tungsten tipped probes are used to pick and place the micro objects.     

压电类智能梁元的力学特性及最优控制

本文分别从压电的传感器和驱动器的力学和电磁学特性入手,详细地描述了带有反馈装置的表面铺设传感器和驱动器的智能梁的力学特性,给出了其微分方程;同时,根据有限元理论,推导了智能梁离散系统的动态微分方程及能量方程在理论分析的基础上,对反馈装置带来的控制力进行优化分析,尽可能地提高了驱动器的使用效率。     

功能梯度压电材料反平面断裂问题研究

基于三维弹性理论和压电理论，导出了材料系统在横观各向同性平面内梯度分布的压电体的状态方程；进而对材料系数按指数函数规律分布的半无限大压电体中的反平面裂纹问题进行了求解；利用Fourier变换给出了半无限大压电体中位移、应力的形式解；并求得了裂纹尖端的应力强度因子及电位移强度因子，分析了不同材料系数及几何因素对它们的影响。     

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.     

Self-Sensing Test Method for the Temperature of Piezoelectric Stacks

A self-sensing test method for the temperature of piezoelectric stack,based on the high correlation between the static capacitance and the stack temperature,is proposed in order to construct a self-sufficient methodology of temperature measurement. Firstly,a theoretical model of static capacitance of the piezoelectric stack under preload was set up,and the influence of preload on the static capacitance was analyzed. Secondly,the correctness of the model was verified by static capacitance test experiments under various preloading conditions. Finally, the temperature measurement experiments at low-temperature stage for two kinds of piezoelectric stacks,namely the lowtemperature-resistant piezoelectric stack and conventional piezoelectric stack, were conducted under various preloading conditions using a polynomial fitting method. The results,which validate the accuracy of the test method,show that the maximum temperature deviations of the two kinds of piezoelectric stack are 3.9 ℃ and 2.8 ℃,respectively,when the preload force is close to the specified value. The test method uses the piezoelectric stack itself as a temperature sensor,which does not require additional equipment for temperature sensing,so that the space and equipment cost could be economized. And the test for static capacitance is concise and convenient,which indicates that in the cooling process,a concise and efficient test of the temperature of the piezoelectric stack could be realized so as to grasp the current temperature change in time.     

双程机电耦合效应对压电层合板机电响应的影响

基于一阶剪切变形理论和压电方程,推导了压电层舍板本构方程,得到一个双程压电-机械耦合的有限元模型,它可以对具有任意分布的表面粘贴式或嵌入式压电传感器和驱动器的复合材料层合板的机电响应进行分析。所得算例的计算结果与文献中的实验结果或ANSYS分析结果非常吻合,也显示了在压电传感器有信号输出时,单程压电-机械耦合的有限元模型所存在的误差。     

面向驱动格尼襟翼应用的压电悬臂梁位移分析

为了设计格尼襟翼的驱动机构,本文对压电悬臂梁自由端的位移及其影响参数进行了研究。采用EulerBernoulli悬臂梁模型给出了压电悬臂梁自由端的位移表达式,并采用有限元法研究了压电悬臂梁的基体厚度和压电片的布置位置等参数对悬臂梁自由端位移的影响。通过两种方法分析了压电悬臂梁自由端的位移变形,研究结果表明,通过解析法和有限元法分别计算得出的压电悬臂梁自由端的位移最大误差不超过3.6%。在其他条件一定的情况下,减小基体厚度、将压电片布置于悬臂梁根部以及选择合适的压电材料能够使自由端获得相对较大的位移。由于压电悬臂梁的位移不能满足格尼襟翼的驱动要求,需采用放大机构进一步放大自由端位移。     

周期分布压电纤维复合材料平面问题研究

为了探索压电纤维复合材料中局部应力场的分布规律和准确预测其有效刚度,基于复变函数理论和线性压电理论,得到了含周期分布压电纤维复合材料平面问题的半解析解.根据单胞内基体和夹杂所占区域的几何特点,分别给出复势函数的级数形式,这些复势函数在基体与夹杂的相邻界面上应满足连续性条件,在单胞的外边界应满足周期性边界条件和远场加载条...     

Electroaeroelastic Modeling and Analysis for Flow Energy Piezoelectric Harvester

An electroaeroelastic model for wind energy harvesting using piezoelectric generators is presented.The flow field is mapped in detail.The force which the fluid flow exerts on the generator is formulated.The output voltage levels generated from the mechanical strain within the piezoelectric elements are determined.An analytical model is developed with consideration of the interactions between the fluid,solid and electric.Various analytical results are obtained,such as flow velocity contour and pressure contour for the flow,moving trajectories,stress contour and output voltage of the harvester.A prototype is fabricated and tested.The simulation result is close to the experimental result.The model developed in this paper can predict the performance and behavior of different energy harvesters.And it also can be used as a design tool for optimizing the performance of the harvester.     

压电固体作动筒及其在结构中的应用

建立了大位移压电固体作动筒（Ｐｉｅｚｏｅｌｅｃｔｒｉｃ ｉｎｄｕｃｅｄ ｓｔｒａｉｎ ａｃｔｕａｔｏｒ, ＰＺＴ ＩＳＡ）的动力学模型。探讨了压电固体作动筒在结构应用中的力学驱动模型,研究了压电作动筒和结构之间的驱动传递关系,以及在结构应用中获得最大输出位移和最大作用力的匹配关系;研究了利用压电作动筒驱动直升机伺服襟翼的一种初步构想以及机械放大机构,用于替代现有的液压装置,对旋翼进行主动减震降噪。同时在不同的频率及负载下,对压电作动筒的驱动性能进行了实验,并作了讨论。结论表明：利用压电作动筒作为直升机伺服襟翼控制的驱动器件,可以实现对伺服襟翼的主动变形及振动控制。