新型压电双晶片式惯性旋转驱动机构设计

提出了一种通过机械方式控制压电驱动机构和接触面间摩擦力矩的有序变化,形成以压电双晶片振子为驱动元件的新型压电惯性旋转驱动机构的研究方案．研究了该机构的运动机理,指出通过改变机构向不同方向运动时和支撑面之间的摩擦系数值,可以实现压电驱动机构的定向运动．对机构惯性冲击力矩的产生、摩擦阻力矩的改变形式进行了分析．设计了压电惯性旋转驱动机构,制作了试验样机,并对相关性能进行了测试试验结果证明该机构可以实现预期的运动.     

基于系统相似方法的叠堆型压电驱动器非线性动力学建模及实验研究

根据机械系统与电气系统的相似方法,将叠堆型压电驱动器的非线性电-机械耦合模型完全转换到电气域内,建立了其非线性相似电路模型;给出了非线性相似电路模型中迟滞因子的辨识方法,并对某款商用叠堆型压电驱动器进行了迟滞因子的辨识试验;基于非线性相似电路模型和迟滞因子的辨识结果,对该款叠堆型压电驱动器的非线性特性进行了仿真分析,得到了其非线性位移迟滞回线;仿真结果与试验结果吻合,证明了该建模过程与辨识方法的正确性。该建模方法在电气域内对叠堆型压电驱动器电-机械耦合特性及非线性迟滞特性进行描述,建模过程物理意义清晰且简单实用,对于研究压电驱动器的动态特性及控制算法具有实际意义。     

新型惯性压电驱动机构的设计与初步实现

提出通过机械方式控制压电驱动机构和支撑面之间摩擦力的有序变化，形成有规律的新型惯性压电驱动机构．分析了机构的运动机理，建立了动力学模型，利用Matlab对机构进行了运动学仿真，设计并制作了驱动机构样机，对驱动机构动态特性进行了仿真分析和试验对比研究．两者结果吻合较好，表明采用简单的对称波形信号能驱动机构运动，直线驱动器最高速度可达1mm／s，最高步长分辨率为20nm，最大承载能力为1000g．     

尺蠖型压电直线驱动器的运动稳定性分析

为了深入研究尺蠖型压电驱动器的性能，分析了尺蠖型压电直线驱动器的工作原理，研究了直线动子对驱动器性能的影响．通过实验方法分析了钳位机构调整前后对钳住稳定性的影响．采用驱动器输出单步位移的步距失稳系数和驱动电压与输出位移拟合曲线斜率和截距偏差率的方法评价尺蠖型压电直线驱动器的运动稳定性．经实验测试发现驱动器的步距失稳系数与驱动电压关系密切，当驱动电压较高时，驱动器具有较好的步距稳定性．驱动器的驱动电压与输出位移拟合曲线斜率和截距偏差率分别为1．8％和9．07％，说明所开发的驱动器具有很好的运动稳定性．     

面向微量试剂分配的压电叠堆泵

微量、快速、精确的试剂分配是生物、制药等领域不可或缺的技术手段.研制了以压电叠堆为驱动器实现高精度、微量化和自动化试剂分配的压电叠堆泵样机.研究了压电叠堆泵的结构、工作原理及加工装配过程.实验研究了不同的输入信号对压电叠堆泵性能的影响和压电叠堆泵的输出流量及压力与输入电压、频率的关系,并将该样机与喷嘴装配在一起组装成试剂泵进行试剂分配实验,研究了试剂泵输出流量及微滴体积与输入电压、频率的关系.测得该压电叠堆泵输出流量的重复精度可达到77.42 μL,喷嘴直径为0.5 mm时试剂泵进行试剂分配的液滴体积为16.09 μL,重复精度为0.29 μL,实现了微量、快速、精确的试剂分配.     

压电喷墨驱动器特性研究及参数优化

目的 研究压电驱动器结构参数对其驱动性能的影响,并对其结构进行优化,为进一步研究压电喷墨的喷射特性奠定基础.方法 总结近年来压电喷墨印刷技术的研究现状,利用有限元数值模拟软件Comsol Multiphysics建立压电驱动器的数值模型,分析压电薄膜PZT、SiO2振动板和Parylene保护层这3个部分的结构尺寸对压电驱动器位移的影响规律,并且利用正交试验方法确定压电驱动器主要部件的最优尺寸.结果 压电驱动器的结构尺寸对其振幅有较大影响,不同的结构组合可以得到不同的压电驱动器位移.在压电薄膜与振动板宽度之比为0.7,振动板宽度为140μm,保护层厚度为0.7μm,振动板厚度为0.9μm,压电薄膜厚度为1μm时,驱动器位移达到最大.结论 通过对压电驱动器的结构尺寸进行优化,可使驱动器位移达到最大,从而使其驱动性能最优.     

新型压电式直线驱动器的研究

介绍了采用带压电元件、圆弧缺口杠杆和双平行四边形弹簧的多级放大一体化结构的新型压电式直线驱动器的研究。实验表明：该直线驱动器的最大行程为４００μｍ，最大输出力为５０Ｎ，可控精度小于０．５μｍ，频带宽为１００Ｈｚ，动作频率为５０Ｈｚ（对应最大行程）。该直线驱动器的特点是驱动力大、可控精度高、响应快、可直接用于ＮＣ机床、机器人装配、活塞加工数控系统的精密直接驱动。     

新型压电陶瓷驱动器的特性分析

讨论了一种基于压电陶瓷的新型叠堆驱动器,并阐述了其工作原理,推导出该驱动器的力学性能公式。基于压电陶瓷材料的机电耦合特性,运用ANSYS有限元软件对此驱动器进行了数值分析,研究了其驱动性能,分析结果表明,其输出位移和输出力均与输入电压呈线性关系,在较低电压下可获得较大变形量,且具有良好的动态响应特性。该叠堆压电驱动器结构简单、尺寸小、成本低,通过输入电压即可实现位移控制,可作为较好的自适应控制驱动器应用于智能摩擦阻尼器的驱动装置。     

腔高对压电液压驱动器性能的影响

为满足大行程、高输出力精密驱动及振动控制的需求,设计了压电叠堆隔膜泵驱动的压电液压驱动器并进行了试验.利用实际液体可压缩的特性,建立了压电液压驱动器理论分析模型,分析了液体体积模量以及压电泵腔高对其输出性能的影响规律.结果表明,其他结构参数确定时压电液压驱动器输出能力随液体体积模量的减小而降低,并存在最佳腔高使其输出能力最大.利用尺寸为4 mm×4 mm×80 mm的压电叠堆制作了泵腔直径30 mm、高度分别为0.3 mm、0.6 mm、0.8 mm、1.0 mm、1.3 mm的压电泵,用于驱动尺寸为20×100 mm3的液压缸.以水为工作介质,在电压150 V、频率60～400 Hz条件下测试了驱动器的输出速度及驱动力.工作频率为300 Hz时,腔高0.6 mm(最佳值)时的输出速度为13.2 mm/s,分别为腔高0.3 mm和1.3 mm时的1.1倍和2.28倍;工作频率为80Hz时,腔高0.3 mm(最小腔高)时的驱动力为105 N,是腔高1.3 mm时驱动力的2.3倍,说明选取合理的泵腔高度可有效提高驱动器的输出性能.     

基于电流控制的压电陶瓷驱动器

为了解决电压控制型压电陶瓷驱动器驱动压电陶瓷时存在的迟滞、蠕变和带宽窄的问题，设计了基于电流控制的压电陶瓷驱动器，利用压电陶瓷致动器位移与其所带电荷量间的线性关系，该驱动器通过控制压电陶瓷的充电电流和时间控制其位移量．在此基础上，提出了以分辨率换取稳定性的动态保持控制方法，采用该电流型驱动器，实现了开环下对压电陶瓷致动器的稳定、快速、高精度定位．实验结果表明，该驱动器驱动行程为10μm的压电陶瓷时，满行程带宽大于1．5kHz，重复定位精度小于4nm（0．4％）．     

电磁辅助压电致动器设计开发与性能测试研究

传统的压电致动器,受限于压电致动的小行程,通常只能测量较小的范围。研发了一种电磁辅助压电致动器,同时具备电磁式致动器长行程与压电式致动器高分辨率的特点,该致动器包含可动件、导引槽、挠性件、电磁铁、压电元件以及控制电路。首先调整挠性可调预压装置并设定电磁铁电流,使得电磁致动力处于最大静摩擦力与动摩擦力之间;再利用压电组件所产生的微震动,控制可动件与导引槽之间的接触情况在静摩擦与动摩擦之间切换,从而完成长行程(10mm)且高分辨率(1.5μm)的往复运动。实验结果表明该致动器具备出色的定位能力。     

新型人工中耳压电振子设计

提出利用压电叠堆作砧骨激励式人工中耳的振子,并利用中耳-压电叠堆耦合力学模型对该压电叠堆振子进行辅助设计。该模型基于一无任何听力损伤病史的成年志愿者的左耳,利用CT扫描和逆向成型技术建成。其可靠性通过与实验对比加以验证。最终设计的压电振子只需要10.5 V的有效驱动电压,便可以对镫骨激起相当于鼓膜处90 dB声压激励的振幅。该振子在频率为1 kHz的单伏电压驱动工况下,能耗仅为0.03 mW,满足人工中耳低电压、低能耗的要求。     

All-fiber Q-switched operation of thulium-doped silica fiber laser by piezoelectric microbending

We demonstrate an all-fiber Q-switched laser operation in the 2 μm region on the basis of a dynamic periodic microbend and pulsed-pump configuration. A single-mode thulium-doped silica fiber is pumped by 1.6 μm-band laser diodes, and the dynamic loss is introduced in the fiber ring resonator by the periodic microbend that is electrically controlled with a piezoelectric actuator. When the voltage-off period of the piezoelectric actuator is set at 20 μs for the pump power of 120 mW, the output pulse power is measured by 420 mW with a pulse width of 1.3 μs.     

Piezoelectric pseudo-shear mode actuator made by L-shape joint bonding

A new type of pseudo-shear mode piezoelectric actuator is described which uses a particular bonding design on a multilayer piezoelectric ceramic stack. In this actuator, long thin rectangular surface electroded PZT piezoelectric sheets are stacked and epoxy bonded at alternate ends. The poling directions in the sheets are selected such that a common potential difference applied to the plates produces alternate lengthening and contraction through the action of d₃₁ and thus a cumulative displacement over the whole length of the effectively folded ceramic. The rectangular stack of plates thus shears over to produce a substantial shear angle, hence the title of pseudo-shear mode actuator. In this paper, a new higher strength bonding for the anchoring of the alternate ends is discussed, and shown to permit the generation of large unloaded surface displacements and a high blocking force.     

Microdisplacement characteristics and microstructures of functionally graded piezoelectric ceramic actuator

In this work, we report a functionally gradient piezoelectric ceramic actuator with sandwiched structure prepared by the powder metallurgical method. The functional gradients of piezoelectric activity and dielectric activity vary inversely across the thickness of the actuator. Such functional gradients are obtained by interdiffusion reaction between a high piezoelectric composition [Pb(Zr,Ti)O₃/PZT] and a high dielectric composition (PbNi_1/3Nb_2/3O₃/PNN). The bending displacement at the free end of the PNN/PZT functionally graded piezoelectric ceramic actuator was approximately 20 m when 1.4-kV/mm electric field was applied. The grain morphology and compositional distribution across the actuator section and the microstructures of the sandwiched layer were investigated by scanned electron microscopy equipped with energy-dispersive spectroscopy, transmission electron microscopy, and selected area electron diffraction patterns, respectively.     

Lead-free piezoelectric-metal-cavity (PMC) actuators

A piezoelectric piezoelectric-metal-cavity (PMC) actuator was reported previously that can exhibit a large flexural displacement. In this paper, a lead-free piezoelectric ceramic was used as a driving element of the PMC actuator. Bi(0.5)(Na(0.725)K(0.175)Li(0.1))(0.5)TiO3 (abbreviated as BNKLT) is a soft-type piezoelectric ceramic with good piezoelectric properties at room temperature. Both the electrical and mechanical properties of the BNKLT PMC actuator were measured. With good piezoelectric coefficients and low density, the BNKLT ceramic has the potential to be used as the driving element of the lead-free actuator.     

Fabrication and experimental characterization of d31 telescopic piezoelectric actuators

A popular and useful piezoelectric actuator is the stack. Unfortunately with this type of actuation architecture the long lengths normally required to obtain necessary displacements can pose packaging and buckling problems. To overcome these limitations, a new architecture for piezoelectric actuators has been developed called telescopic. The basic design consists of concentric shells interconnected by end-caps which alternate in placement between the two axial ends of the shells. This leads to a linear displacement amplification at the cost of force; yet the force remains at the same magnitude as a stack and significantly higher than bender type architectures. This paper describes the fabrication and experimental characterization of three different telescopic prototypes. The actuator prototypes discussed in this paper mark a definitive step forward in fabrication techniques for complex piezoceramic structures. Materials Systems, Inc. has adapted injection molding for the fabrication of net shape piezoceramic actuators. Injection molding provides several advantages over conventional fabrication techniques, including: high production rate, uniform part dimensions, uniform piezoelectric properties, and reduced fabrication and assembly costs. Acrylate polymerization, developed at the University of Michigan, is similar to gelcasting, but uses a nonaqueous slurry which facilitates the production of large, tall, complex components such as the telescopic actuator, and is ideal for the rapid manufacture of unique or small batch structures. To demonstrate these fabrication processes a five tube telescopic actuator was injection molded along with a very tall three tube actuator that was cast using the acrylate polymerization method. As a benchmark, a third actuator was built from off-the-shelf tubes that were joined with aluminum end-caps. Each prototype's free deflection behavior was experimentally characterized and the results of the testing are presented within this paper.     

Theoretical calculations and performance results of a PZT thin film actuator

High piezoelectric coupling coefficients of PZT-based material systems can be employed for actuator functions in micro-electro-mechanical systems (MEMS) offering displacements and forces which outperform standard solutions. This paper presents simulation, fabrication, and development results of a stress-compensated, PZT-coated cantilever concept in which a silicon bulk micromachining process is used in combination with a chemical solution deposition (CSD) technique. Due to an analytical approach and a finite element method (FEM) simulation for a tip displacement of 10 /spl mu/m, the actuator was designed with a cantilever length of 300 /spl mu/m to 1000 /spl mu/m. Special attention was given to the Zr/Ti ratio of the PZT thin films to obtain a high piezoelectric coefficient. For first characterizations X-ray diffraction (XRD), scanning electron microscopy (SEM), hysteresis-, current-voltage I(V)and capacitance-voltage C(V)-measurements were carried out.