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薄膜润滑 5

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Piezoelectric film-actuated motion platform with high resolution

HUA Shunming, ZHANG Hongzhuang, CHENG Guangming, FAN Zunqiang, LIU Jianfang

《机械工程前沿（英文）》 2008年第3卷第3期页码 265-269 doi: 10.1007/s11465-008-0041-2

摘要： A piezoelectric film-actuated motion platform with high resolution, which can run in two directions within a horizontal plane, is presented. On the basis of the analysis of the working principle of a stick-slip mechanism, a mathematical model describing its dynamic behavior is set up and simulated. Experiments of the motion performance and carrying ability on the prototype are conducted. Results show that this type of platform has advantages including a simple structure, small volume, light weight, stable step length, and large traveling range. When the driving voltage is less than 30 V, step error is less than 0.5 ?m. The carrying ability of the platform is terrific and about 7–8 times its weight.

关键词： mathematical stick-slip mechanism piezoelectric film-actuated analysis terrific

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Preload characteristics identification of the piezoelectric-actuated 1-DOF compliant nanopositioning

Ruizhou WANG, Xianmin ZHANG

《机械工程前沿（英文）》 2015年第10卷第1期页码 20-36 doi: 10.1007/s11465-015-0328-z

摘要：

Packaged piezoelectric ceramic actuators (PPCAs) and compliant mechanisms are attractive for nanopositioning and nanomanipulation due to their ultra-high precision. The way to create and keep a proper and steady connection between both ends of the PPCA and the compliant mechanism is an essential step to achieve such a high accuracy. The connection status affects the initial position of the terminal moving plate, the positioning accuracy and the dynamic performance of the nanopositioning platform, especially during a long-time or high-frequency positioning procedure. This paper presents a novel external preload mechanism and tests it in a 1-degree of freedom (1-DOF) compliant nanopositioning platform. The 1-DOF platform utilizes a parallelogram guiding mechanism and a parallelogram load mechanism to provide a more accurate actual input displacement and output displacement. The simulation results verify the proposed stiffness model and dynamic model of the platform. The values of the preload displacement, actual input displacement and output displacement can be measured by three capacitive sensors during the whole positioning procedure. The test results show the preload characteristics vary with different types or control modes of the PPCA. Some fitting formulas are derived to describe the preload displacement, actual input displacement and output displacement using the nominal elongation signal of the PPCA. With the identification of the preload characteristics, the actual and comprehensive output characteristics of the PPCA can be obtained by the strain gauge sensor (SGS) embedded in the PPCA.

关键词： nanopositioning preload characteristic packaged piezoelectric ceramic actuator compliant mechanism

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Development of a redundant anthropomorphic hydraulically actuated manipulator with a roll–pitch–yaw spherical

《机械工程前沿（英文）》 2021年第16卷第4期页码 698-710 doi: 10.1007/s11465-021-0646-2

摘要： The demand for redundant hydraulic manipulators that can implement complex heavy-duty tasks in unstructured areas is increasing; however, current manipulator layouts that remarkably differ from human arms make intuitive kinematic operation challenging to achieve. This study proposes a seven-degree-of-freedom (7-DOF) redundant anthropomorphic hydraulically actuated manipulator with a novel roll–pitch–yaw spherical wrist. A hybrid series–parallel mechanism is presented to achieve the spherical wrist design, which consists of two parallel linear hydraulic cylinders to drive the yaw/pitch 2-DOF wrist plate connected serially to the roll structure. Designed as a 1R PRRR-1S PU mechanism (“R”, “P”, “S”, and “U” denote revolute, prismatic, spherical, and universal joints, respectively; the underlined letter indicates the active joint), the 2-DOF parallel structure is partially decoupled to obtain simple forward/inverse kinematic solutions in which a closed-loop subchain “R PRR” is included. The 7-DOF manipulator is then designed, and its third joint axis goes through the spherical center to obtain closed-form inverse kinematic computation. The analytical inverse kinematic solution is drawn by constructing self-motion manifolds. Finally, a physical prototype is developed, and the kinematic analysis is validated via numerical simulation and test results.

关键词： hydraulic manipulator inverse kinematic redundant design spherical wrist

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Research on applications of piezoelectric materials in smart structures

Jinhao QIU, Hongli JI

《机械工程前沿（英文）》 2011年第6卷第1期页码 99-117 doi: 10.1007/s11465-011-0212-4

摘要：

Piezoelectric materials have become the most attractive functional materials for sensors and actuators in smart structures because they can directly convert mechanical energy to electrical energy and vise versa. They have excellent electromechanical coupling characteristics and excellent frequency response. In this article, some research activities on the applications of piezoelectric materials in smart structures, including semi-active vibration control based on synchronized switch damping using negative capacitance, energy harvesting using new electronic interfaces, structural health monitoring based on a new type of piezoelectric fibers with metal core, and active hysteresis control based on new modified Prandtl-Ishlinskii model at the Aeronautical Science Key Laboratory for Smart Materials and Structures, Nanjing University of Aeronautics and Astronautics are introduced.

关键词： piezoelectric materials vibration control energy harvesting structural health monitoring piezoelectric hysteresis

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Present situation and classification of piezoelectric pump

Fang YE, Shouyin WANG, Wei CHENG, Qixiao XIA, Jianhui ZHANG,

《机械工程前沿（英文）》 2009年第4卷第4期页码 420-429 doi: 10.1007/s11465-009-0052-7

摘要： According to the present classification method for a piezoelectric pump, this paper reviews the development and present situation of piezoelectric pumps in the latest 30 years and finally puts forward a new classification. A volumetric piezoelectric pump, which belongs to traditional volumetric pumps, can be divided into a piezoelectric pump with or without valves. A new valveless piezoelectric pump nowadays becomes a hot issue in scientific research. It is constructed by using no-moving-part valves, which can induce positive flow resistance and negative flow resistance different, and in which the inlet and outlet are connected all the time. New forms of piezoelectric pumps, different from traditional ones, are only at the stage of conception and principle, and no practical application has been reported.

关键词： piezoelectric pump development and present situation new classification method valveless piezoelectric pump new forms of piezoelectric pump

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Robust isogeometric topology optimization for piezoelectric actuators with uniform manufacturability

《机械工程前沿（英文）》 2022年第17卷第2期 doi: 10.1007/s11465-022-0683-5

摘要： Piezoelectric actuators have received substantial attention among the industry and academia due to quick responses, such as high output force, high stiffness, high accuracy, and precision. However, the design of piezoelectric actuators always suffers from the emergence of several localized hinges with only one-node connection, which have difficulty satisfying manufacturing and machining requirements (from the over- or under-etching devices). The main purpose of the current paper is to propose a robust isogeometric topology optimization (RITO) method for the design of piezoelectric actuators, which can effectively remove the critical issue induced by one-node connected hinges and simultaneously maintain uniform manufacturability in the optimized topologies. In RITO, the isogeometric analysis replacing the conventional finite element method is applied to compute the unknown electro elastic fields in piezoelectric materials, which can improve numerical accuracy and then enhance iterative stability. The erode–dilate operator is introduced in topology representation to construct the eroded, intermediate, and dilated density distribution functions by non-uniform rational B-splines. Finally, the RITO formulation for the design of piezoelectric materials is developed, and several numerical examples are performed to test the effectiveness and efficiency of the proposed RITO method.

关键词： piezoelectric actuator isogeometric topology optimization uniform manufacturability robust formulation density distribution function

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Optimal design of a linkage–cam mechanism-based redundantly actuated parallel manipulator

《机械工程前沿（英文）》 2021年第16卷第3期页码 451-467 doi: 10.1007/s11465-021-0634-6

摘要： A redundantly actuated parallel manipulator (RAPM) with mixed translational and rotational degrees of freedom (DOFs) is challenged for its dimensionally homogeneous Jacobian modeling and optimal design of architecture. In this paper, a means to achieve redundant actuation by adding kinematic constraints is introduced, which reduces the DOFs of the end-effector (EE). A generic dimensionally homogeneous Jacobian is developed for this type of RAPMs, which maps the generalized velocities of three points on the EE to the joint velocities. A new optimization algorithm derived from this dimensionally homogeneous Jacobian is proposed for the optimal design of this type of RAPMs. As an example, this paper presents a spatial RAPM involving linkages and cam mechanisms. This RAPM has 4 DOFs and 6 translational actuations. The linkage lengths and the position of the universal joints of the RAPM are optimized based on the dimensionally homogeneous Jacobian.

关键词： redundant actuation parallel manipulator linkage–cam mechanism Jacobian optimal design

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Novel precision piezoelectric step rotary actuator

LIU Jianfang, YANG Zhigang, ZHAO Hongwei, CHENG Guangming

《机械工程前沿（英文）》 2007年第2卷第3期页码 356-360 doi: 10.1007/s11465-007-0062-2

摘要： A novel piezoelectric (PZT) precision step rotary actuator was developed on the basis of PZT technology. It adopts the principle of bionics and works with an inside anchoring/loosening of the stator and a distortion structure of the uniformly distributed thin flexible hinge to solve problems such as ineffective anchoring/loosening, low step rotary frequency, small travel, poor resolution, low speed and unsteady output. The developed actuator is characterized by high frequency (30 Hz), high speed (380 μrad/s), large travel (>270º), high resolution (1 μrad/step), and work stability. It greatly improves the ability to drive the existing PZT step rotary actuator. The new actuator can be applied in the field of micromanipulation and precision engineering, including precision driving and positioning and optics engineering.

关键词： developed stability ineffective anchoring/loosening technology piezoelectric

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A valveless piezoelectric pump with novel flow path design of function of rectification to improve energy

《机械工程前沿（英文）》 2022年第17卷第3期 doi: 10.1007/s11465-022-0685-3

摘要： Existing valveless piezoelectric pumps are mostly based on the flow resistance mechanism to generate unidirectional fluid pumping, resulting in inefficient energy conversion because the majority of mechanical energy is consumed in terms of parasitic loss. In this paper, a novel tube structure composed of a Y-shaped tube and a ȹ-shaped tube was proposed considering theory of jet inertia and vortex dissipation for the first time to improve energy efficiency. After verifying its feasibility through the flow field simulation, the proposed tubes were integrated into a piezo-driven chamber, and a novel valveless piezoelectric pump with the function of rectification (NVPPFR) was reported. Unlike previous pumps, the reported pump directed the reflux fluid to another flow channel different from the pumping fluid, thus improving pumping efficiency. Then, mathematical modeling was established, including the kinetic analysis of vibrator, flow loss analysis of fluid, and pumping efficiency. Eventually, experiments were designed, and results showed that NVPPFR had the function of rectification and net pumping effect. The maximum flow rate reached 6.89 mL/min, and the pumping efficiency was up to 27%. The development of NVPPFR compensated for the inefficiency of traditional valveless piezoelectric pumps, broadening the application prospect in biomedicine and biology fields.

关键词： composite tube valveless piezoelectric pump rectification energy efficiency

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Analysis of suitable geometrical parameters for designing a tendon-driven under-actuated mechanical finger

Francesco PENTA,Cesare ROSSI,Sergio SAVINO

《机械工程前沿（英文）》 2016年第11卷第2期页码 184-194 doi: 10.1007/s11465-016-0385-y

摘要：

This study aims to optimize the geometrical parameters of an under-actuated mechanical finger by conducting a theoretical analysis of these parameters. The finger is actuated by a flexion tendon and an extension tendon. The considered parameters are the tendon guide positions with respect to the hinges. By applying such an optimization, the correct kinematical and dynamical behavior of the closing cycle of the finger can be obtained. The results of this study are useful for avoiding the snap-through and the single joint hyperflexion, which are the two breakdowns most frequently observed during experimentation on prototypes. Diagrams are established to identify the optimum values for the tendon guides position of a finger with specified dimensions. The findings of this study can serve as guide for future finger design.

关键词： tendon-driven fingers mechanical finger design under-actuated mechanical systems

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Boundary conditions for axisymmetric piezoelectric cylinder

Baosheng ZHAO, Di WU, Xi CHEN

《机械工程前沿（英文）》 2013年第8卷第4期页码 401-408 doi: 10.1007/s11465-013-0272-8

摘要：

For axisymmetric piezoelectric cylinder, the reciprocal theorem and the axisymmetric general solution of piezoelasticity are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all orders for the cylinder of general edge geometry and loadings. A decay analysis technique developed by Gregory and Wan is converted into necessary conditions on the end-data of axisymmetric piezoelectric circular cylinder, and the rapidly decaying solution is established. The prescribed end-data of the circle cylinder must satisfy these conditions in order that they could generate a decaying state within the cylinder. When stress and mixed conditions are imposed on the end of cylinder, these decaying state conditions for the case of axisymmetric deformation of piezoelectric cylinder are derived explicitly. They are then used for the correct formulation of boundary conditions for the theory solution (or the interior solution) of axisymmetric piezoelectric cylinder. The results of the present paper enable us to establish a set of correct boundary conditions, most of which are obtained for the first time.

关键词： solid and structures the axisymmetric deformation the piezoelectric circular cylinder the refined theory Bessel’s Function

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Comparison between four piezoelectric energy harvesting circuits

Jinhao Qiu, Hao Jiang, Hongli Ji, Kongjun ZHU

《机械工程前沿（英文）》 2009年第4卷第2期页码 153-159 doi: 10.1007/s11465-009-0031-z

摘要： This paper investigates and compares the efficiencies of four different interfaces for vibration-based energy harvesting systems. Among those four circuits, two circuits adopt the synchronous switching technique, in which the circuit is switched synchronously with the vibration. In this study, a simple source-less trigger circuit used to control the synchronized switch is proposed and two interface circuits of energy harvesting systems are designed based on the trigger circuit. To validate the effectiveness of the proposed circuits, an experimental system was established and the power harvested by those circuits from a vibration beam was measured. Experimental results show that the two new circuits can increase the harvested power by factors 2.6 and 7, respectively, without consuming extra power in the circuits.

关键词： energy harvesting piezoelectric materials synchronized switching

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Performance analysis of piezoelectric bimorph generator

KAN Junwu, TANG Kehong, ZHAO Hongwei, SHAO Chenghui, ZHU Guoren

《机械工程前沿（英文）》 2008年第3卷第2期页码 151-157 doi: 10.1007/s11465-008-0039-9

摘要： In this paper, the theoretical model and simulation of the performance of a piezoelectric (PZT) bimorph generator is introduced. The generator consists of two piezoelectric plates bonded on a substrate metal plate. For an effective electromechanical coupling coefficient (EECC) and the generated energy, the analytical formulae are established with the thickness ratio and the Young’s modulus ratio as variables. After giving correlative material parameters, the EECC and generated energy can be computed. The results show that there is a optimal thickness ratio for a piezoelectric bimorph generator to achieve the maximum EECC and electrical energy. The EECC and generated energy decrease with an increase of the Young’s modulus ratio. In addition, the influence of mechanical source on electrical energy generation and power output is also considered.

关键词： piezoelectric bimorph substrate addition PZT mechanical

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Spectral element modeling based structure piezoelectric impedance computation and damage identification

Zhigang GUO, Zhi SUN

《结构与土木工程前沿（英文）》 2011年第5卷第4期页码 458-464 doi: 10.1007/s11709-011-0133-7

摘要： This paper presents a numerical simulation study on electromechanical impedance technique for structural damage identification. The basic principle of impedance based damage detection is structural impedance will vary with the occurrence and development of structural damage, which can be measured from electromechanical admittance curves acquired from PZT patches. Therefore, structure damage can be identified from the electromechanical admittance measurements. In this study, a model based method that can identify both location and severity of structural damage through the minimization of the deviations between structural impedance curves and numerically computed response is developed. The numerical model is set up using the spectral element method, which is promised to be of high numerical efficiency and computational accuracy in the high frequency range. An optimization procedure is then formulated to estimate the property change of structural elements from the electric admittance measurement of PZT patches. A case study on a pin-pin bar is conducted to investigate the feasibility of the proposed method. The results show that the presented method can accurately identify bar damage location and severity even when the measurements are polluted by 5% noise.

关键词： PZT piezoelectric impedance optimization spectral element damage identification

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Low crosstalk switch unit for dense piezoelectric sensor networks

Lei QIU, Shenfang YUAN,

《机械工程前沿（英文）》 2009年第4卷第4期页码 401-406 doi: 10.1007/s11465-009-0047-4

摘要： Structural health monitoring (SHM), on the basis of piezoelectric (PZT) sensors and lamb wave method, is efficient in estimating the state of monitored structures. Furthermore, to monitor large-scale structures, dense piezoelectric sensor networks are required, which usually contain many piezoelectric sensor pairs called actuator-sensor channels. In that case, considering the few data acquisition channels especially in the data acquisition board with a high sampling rate and limited quantity of signal amplifiers used in an integrated computer system, a switch unit is adopted to switch to different channels. Because of the high frequency and power of the lamb wave excitation signal, there exists a crosstalk signal in the switch unit. A large crosstalk signal is mixed into the response signal so that the on/off-line signal processing task is difficult to achieve. This paper first analyzes the crosstalk signal phenomenon, describes its production mechanism, and proposes a method to reduce it. Then a 24-switch channel low crosstalk switch unit based on a digital I/O board PCI7248 produced by Adlink technology is developed. An experiment is implemented to validate it. Its low crosstalk characteristics make it promote the real application of the SHM based active lamb wave method. Finally, a general software program based on LabVIEW software platform is developed to control this switch unit.

关键词： structural health monitoring (SHM) piezoelectric (PZT) sensor networks switch unit crosstalk signal