Papers by Author: Xiang Cheng Chu

Abstract: Based on piezoceramic stack actuators, a stage (dimension of 50mm×50mm×11mm) with a symmetric displacement magnifying mechanism is studied in this paper. FEM simulations are carried out to reveal the performance of the micropositioning stage and the amplification radio of the flexure hinge is 4.76. The working mode of the flexure hinge of the stage is also simulated by finite element method, and its natural frequency is 3291Hz. A series of tests about piezoceramic stack actuators have been done, including static, dynamic and temperature tests. The experimental results are identical to the theoretical analysis and give help to the application of piezoceramic stack actuators. It can also help the precise micropositioning stage driven by PZT to achieve higher positioning accuracy and resolution.

Abstract: In this paper, a kind of Mg, Nb co-doped multilayer piezoelectric ceramic is prepared and a non-contact accurate testing method is introduced. Using Pb(Mg1/3Nb2/3)O3- Pb(Ni1/3Nb2/3)O3- Pb(ZrTi)O3 low temperature co-fired ceramics powder and 90/10 Ag-Pb internal electrodes, the sample is prepared with tape casting processing method and low temperature co-fired technique at 960°C. Based on non-contact method, the piezoelectric constant, butterfly curve, and temperature characters are tested. Experiments show that non-contact method is more accurate for d33 testing. The effect of mechanical load on piezoelectric performance is also investigated. Under external mechanical load, switching polarization (Ps) and remnant polarization (Pr) increase respectively. Mechanical load press is also favorable to dominate the temperature rise of the piezoelectric device.

Abstract: A novel model of 3-DOF multilayer PZT micromanipulator is promoted and simulated with finite element analysis method. States under different applied voltages were discussed, including the motion along axis Z and the rotation along axis X and the bisector between X-Y. After analyzing the distribution of stress, we propose some method, which helps to improve the performance of the micromanipulator. We also do some quantificational analysis about the micromanipulator, discovering that the relationship between the displacements of the probe and applied voltages is almost perfectly linear. By comparing the constant D defining the relationship of the displacements of probe tip and applied voltages, the simulation is proved to be correct. Comparing the performance between the single-layer and multi-layer PZT, it shows that the multi-layer PZT can reduce input voltages, whereas can produce the same displacement. Ceramic sample is prepared for further experiment.

Abstract: A novel rotary piezoelectric micro-motor (φ8mm×10mm) is proposed in this paper. Different from the conventional traveling wave ultrasonic motor using piezoelectric ceramic ring, four multilayer co-firing piezoelectric ceramic bulks (2mm×2mm×3mm) are used to generate vibration in the ring type stator. The layout and electric signals applied to the piezoelectric ceramic bulks are designed for the purpose of generating elliptical trajectories on the surface of the stator. The working mode of the prototype motor is simulated by the finite element method, and also measured by the Doppler Laser Vibrometer. The experimental results are in good agreement with simulation, which verifies the effectiveness of the finite element model. The prototype motor is driven at the low voltage of 12V under the frequency of 64.91 KHz.

Abstract: A micro piezoelectric motor with a disk-pivot structure is presented. Different from conventional wobble-type piezoelectric motor using piezoelectric rod or cylinder, piezoelectric disc is used to excite wobble modes and metal cylinder stator is used to amplify the transverse displacement, metal rod rotor is actuated to rotate. The outer diameter of the actuator is 14mm. In this paper, the performances of the motor are characterized, where a high rotation speed and a high toque are obtained. The property of start-up period movement of the motor was studied by a high-speed camera. The toque of the motor was calculated by the property of the start-up movement.

Abstract: This article describes out-of-plane resonant modes of a piezoelectric disc structure. A new type of micro ultrasonic motor using the resonant mode B11 (Bmn, where m is the number of nodal circles, n is the number of nodal diameters) has been studied. The motor is a wobble-type motor. The stator of the motor uses this structure, consisting of a hollow metal cylinder and a piezoelectric ceramic disc bonded with a metal one, which is excited in the vibration mode by two electrical signals. The stator exhibits wobble displacement and transfers rotation to a rod rotor by the cylinder. The behavior of the stator has been simulated by the finite element analysis. The simulation results have been checked with laser scanning by a laser scanning vibrometer. The article closes with the introduction of the new micro ultrasonic motors based on this vibration mode with high rotation speed.

Abstract: The dynamic behavior of a vibration converter of an ultrasonic motor is described using finite element method. Tetrahedral finite elements with three dimensions are formulated with the effects of piezoelectric coupling. And the solution of the coupled electroelastic equations of dynamic motion is presented. The simulated response of the vibration converter is calculated, and shows excellent consistency with experimental results, which proved that finite element modeling is a good approach to optimize piezoelectric apparatus design. A gradual optimized method is employed to ascertain the most compatible structure.

Abstract: Lead zirconate titanate (PZT) thin films with a composition near the morphotropic phase boundary were deposited on silicon wafers by using a modified sol-gel method. Introducing a seeding layer between the interface of PZT film and platinum electrode controlled the texture of PZT films. The lead oxide seeding layer results in highly (001)-textured PZT film, while the titanium dioxide seeding layer results in (111)-textured one. SEM and XRD were used to characterize the PZT thin films. The ferroelectric and piezoelectric properties of the PZT films were evaluated and discussed in association with different preferential orientations.

Abstract: Pb(Zr,Ti)O3 (PZT) thin films have attracted great attention due to their superior ferroelectric, pyroelectric and piezoelectric properties. The epitaxial films on single-crystal substrates are expected to possess enhanced properties compared with polycrystalline films on conventional silicon wafers. We prepared epitaxial PZT films on STO (STO) substrates with different orientation by using a sol-gel method. The preparation parameters were optimized to improve crystallization of the films. Although the films were of the same composition and prepared under the same condition, different crystal phases with corresponding preferential film orientations were formed when the substrate orientation was changed. [001]-oriented tetragonal PZT film was formed on the {100} surface of the STO substrate, whereas [111]-oriented rhombohedral PZT film on the {111} surface.