Papers by Keyword: Piezoelectric Actuator

Abstract: To resolve such problems as higher electrode wear and low machining efficiency of micro-EDM, a new piezoelectric self-adaptive micro electrical discharge machining system (PSMEDM), based on inverse piezoelectric effect, was developed in this paper. In this new system, a piezoelectric actuator with high frequency response was applied as the micro feeding system to regulate the discharge gap. The machining mechanism and machining process were elaborated. The paper focus on the planning of PSMEDM process and the electrode wear problem. Special attention is paid on the influence of machining parameters such as open voltage, capacitance, resistance, spindle rotational speed and initial feed speed on machining efficiency by using signal to noise analysis method based on orthogonal experiment.

Abstract: In this research, our research team used the self-designed piezoelectric actuator to achieve the micro/nanometer level precise positioning biaxial piezoelectric actuated stage through the redesign of stage mechanism. A novel piezoelectric actuator structure - 4-9-9-14 piezoelectric actuator is constructed, and it is made of piezoelectric buzzer to drive the stage. The movement of the piezoelectric actuated stage is read and analyzed by means of NI PCI-6115 data acquisition card and LabVIEW software operating in conjunction with a linear encoder. The new consideration of tuning time T_on is used to place of traditional method of changing the magnitude of driving voltage to control the stepping distance of the stage. Under a constant driving voltage, the displacement of the stage increases with time T_on, and the displacement of the stage decreases with time T_on. The aforesaid phenomenon occurs to leftward or rightward movement of the upper stage and forward or backward movement of the lower stage. Given a constant time T_on, the displacement of the stage in motion decreases with the driving voltage, and the displacement of the stage in motion increases with the driving voltage.

Abstract: A novel design of the semi-elliptical motor based on a double-mode type ultrasonic motor is proposed and analyzed in this paper. Due to the simplification, the semi-elliptical piezoelectric motor can be considered as an improvement of the elliptical piezoelectric motor which we have proposed in the past. The composite structure of the stator in the motor is formed by two multilayer piezoelectric actuators clamped in a semi-elliptical elastic body. In the simulation, finite element modeling of the motor is performed. The geometry of the stator has been computed with the help of the finite element analysis. Then, the dimensions of the stator's structure were determined by making the two resonance frequencies close to each other. In the experiments, the impedance and the displacement response are measured and discussed for understanding the characteristics of the linear piezoelectric motor with a semi-elliptical stator. The motor achieved maximum moving speed of 96 mm/s and the maximum output force of 0.64 N when applying a sine wave of 14V_r driving voltage at 21.2 kHz, while the maximum moving speed of 132 mm/s and the maximum output force of 0.88 N can be achieved if applying two signal driving method of the same voltage.

Abstract: The bridge-type displacement amplifier is modeled by the analytical method and finite element method. The analytical relationship between the input displacement and output displacement is established. The analytical model is validated by finite element method. The geometric parameters influence of amplification ratio is studied. The comparison results show that the link length and the link angle influence the amplification ratio dramatically. A small link angle and a large link length is beneficial to the amplification ratio. The finite element method has a more precise simulation results than the analytical method under the circumstance of small link angle and short link length.

Abstract: A simplified smart flexible spatial piezoelectric beam with overall motions is studied in this paper. Considering the geometrically nonlinear effect resulting from curved and twisted deformations, and considering the kinetic energy of the piezoelectric actuator and the coupled terms of deformations in the longitudinal, lateral and transversal directions, and taking into account the coupling of electric performance of piezoelectric material and structure deformation, finally, the Rigid-flexible-electric coupling dynamic model of piezoelectric smart beam is established by infinite element method and Lagrange equation.

Abstract: Piezoelectric actuators (PEAs) have been widely used in micro fabrication. But the hysteresis inherited in PEAs leads to a severe inaccuracy and deteriorated tracking performance. In this paper, a hysteresis observer is designed for PEAs to estimate the hysteresis, mechanical parameter varieties, positioning error and external disturbance. A Bouc-Wen model is associated with a linear second-order mass-damping-spring trio to model the dynamics. An asymptotic sliding surface is selected. Lyapunov stability theory is applied to guarantee the asymptotical stability for the trajectory tracking error. Experiments are conducted to validate the effectiveness of the proposed method. Results show that a satisfied tracking response to a sinusoidal trajectory is achieved, and the positioning errors under a triangle scanning contour are dramatically reduced compared with the traditional SMC.

Abstract: This paper covers the development of two piezoelectric actuators for trailing edge flap control on mach scaled model helicopter rotors. The design, analysis and bench tests of these two actuators are described. Under different voltages and frequencies, their drive performances are tested and compared. Results showed that these two actuators all can effectively drive and control the flaps with each advantages and disadvantages.

Abstract: Piezoelectric actuator has the characteristics of high displacement resolution, fast dynamic response, miniature size and etc. But its inherent hysteresis nonlinear affects its positioning accuracy. This paper analysis the hysteresis nonlinear characteristics of piezoelectric actuator, verifies the effect of hysteresis nonlinear on piezoelectric actuator, and compensate the hysteresis nonlinear characteristics by using the integrated control algorithm of feed-forward control and PI control, which can improve the control precision of the piezoelectric actuator.

Abstract: This paper mainly proposes a chaos particle swarm optimization (CPSO) to estimate the parameters of piezoelectric actuator (PEA), in which Bouc-Wen model is employed to describe the hysteresis phenomenon. By introducing chaotic disturbance to the simple PSO, this method can obtain optimal solution with high calculation efficiency. Finally some experiments are conducted to demonstrate its feasibility and effectiveness.

Abstract: The paper deals with improving the mechanical characteristics of piezoelectric actuators. This type of actuators can be found in many mechatronic systems, but they have a great disadvantage consisting in the small displacements they produce. The paper presents five mechanical structures designed and manufactured to amplify the displacements produced by piezoelectric actuators.