Papers by Keyword: Piezoelectric Actuator

Abstract: This paper demonstrates the feasibility of using piezoelectric actuators in controlling flow-induced vibration of a lightweight composite wing structure. Vibration characteristics of the composite wing model were predicted analytically against the air flow speed and the results were compared with experimental results from wind tunnel tests. Vibration control tests were successfully accomplished using positive position feedback (PPF) controller and the real-time operating deflection shapes of the composite wing were measured using 3D optical motion capture system.

Abstract: The compliant mechanisms are mechanical devices which provide smooth and controlled motion guidance due to the deformation of some or all of the components. In this paper an original compliant minigripper is designed and analyzed. An experimental prototype of the compliant minigripper was developed. It is characterized by a compact design and easy connection to the piezoelectric actuator that amplifies the input displacement.

Abstract: A 6-DOF monolithic nanopositioning stage is developed for three coordinate measuring machines (CMM) with nanometer resolution. The stage consists of a monolithic flexure hinge mechanism, six piezoelectric actuators and six fiber-optic displacement sensors. A mathematical model of the constraint optimization problem is presented. Based on the solution of the optimization problem, the final design of the 6-DOF stage is also presented. The numerical analysis on static and dynamic behavior of the stage is done by using the finite element method. The experimental results of the performance of the 6-DOF stage are presented.

Abstract: A functionally gradient piezoelectric actuator based on PbNi1/3Nb2/3O3-PbZrO3-PbTiO3 (PNN-PZ-PT) system was prepared. The cantilevered actuator consists of a high piezoelectric & low dielectric layer, a low piezoelectric & high dielectric layer and a thin middle diffusion layer. Frequency dependences of impedance were measured from 100Hz to 3MHz. The resonance modes were characterized. A number of low frequency modes were observed and identified as bending resonance. The dimension dependence of resonance frequency of bending resonance was investigated. The results of the measurement were compared with calculated values. There is a good agreement between the determined resonance frequencies and calculated values.

Abstract: A kind of experimental platform for in-situ nanoindentation and scratch test has been developed, which has high resolution of displacement and can be used to carry out nanoindentation and scratch test. The precision driven element composing of flexure hinges and piezoelectric actuator was analyzed, which was used to realize indenter’s precision motion. The components, working principle and performances of testing platform were introduced. The calibration experiments of loading and displacement sensors were carried out, and it showed loading and displacement sensors had high linearity and stability. The indentation experiments were carried out on a kind of glass. The experimental results showed proposed testing platform had good reproducibility and scheme was feasible. The research work will provide theoretical foundation and key technologies for nanomechanics test, and has theoretical significance and application value to materials science, micro-electronics, precision optics and biomechanics, etc.

Abstract: In order to improve the accuracy of position for the machine, a micro-displacement stage is deigned based on piezoelectric actuator and flexible hinge. The structure of the flexible hinge is analyzed reasonably. With the hybrid method of feedforward and digital PID control, the control process of the micro-displacement stage can be corrected and compensated. It is indicated by experiment that the maximum stroke of the micro-displacement stage is , and the position accuracy is , which can meet the requirement of precision and ultra-precision machining.

Abstract: Combining the constitutive equation of piezoelectric ceramic with elastic-dynamical equations and coupling theory of FEM, the finite element control equation for piezoelectric actuator is established. Detailed calculation of the electro-mechanical coupling field parameters is made by the SP1 type longitudinal-bending vibrator and results show it can be used for the transparent calculation for piezoelectric intellectual structure and avoid the black box operation in FEM software. The model lays the foundation to develop the special program for piezoelectric actuator and to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power.

Abstract: This paper presents the results of an experimental investigation on the use of piezoelectric materials as a technique for monitoring the growth of defects in structures. The method consists of exciting the structure with piezoelectric actuators while recording the electromechanical responses from sensors placed close to the defect. The piezoelectric sensors detect the damage growth or an incipient defect by monitoring changes in the dynamic strain field, induced by the piezoelectric actuator, near the defect. This technique was evaluated through experiments using an aluminum frame structure. Results show that the piezoelectric active method is capable of detecting small changes in defect depth.

Abstract: In this paper, we describe a mcromanipulate mechanism used the converse piezoelectric effects, The micro-step mechanism based on converse piezoelectric effects is designed. Alternative signals programming from the computer is driving the piezo actuator by means of a dynamic power. The micro step motion of the the micro-step mechanism is realized used the electrostrictive effect and alternative clamping the guide staff, the position of Micro-step Mechanism is precise controlled.Micro gripper that actuated by piezoelectric cantilever was developed for the need of micro parts assembly.

Abstract: The purpose of this paper is to investigate the optimal placement of piezoelectric actuator for active vibration control of smart structure. The structures can be described in the modal space based on the independent modal space control method and dynamic equations derived from finite element model. The modal damping ratios are derived from modal equations and an optimal target is given by maximizing the modal damping ratios. Accumulation method is adopted to the optimization calculation. Simulations are carried out for active vibration control of a conical shell with distributed piezoelectric actuators. Control effects proved the validity of the optimal method above by compared with the non-optimal results. The optimal method in this paper gives a useful guide for quantity optimization of actuators to piezoelectric structures.