减小压电陶瓷驱动电源纹波的一种有效方法

为了解决直流放大式压电陶瓷驱动电源在实际应用中存在输出电压纹波较大且幅值随输出电压大小而改变的问题，对其工作原理进行了深入分析，在此基础上提出了采用恒流源代替基在级电路负载的方法。实验表明，这种有效地抑制了电源的纹波及其变化。     

Computational analysis on cymbal transducer

Finite Element Analysis in collaboration with experimental studies was conducted to investigate the effects of dimensional parameters on the performance of the cymbal transducer. ANSYS 5.5 FEM code was used for computational analysis. Cymbal transducers were fabricated with steel and brass endcap materials and piezoelectric ceramic, PZT-5A, as driving elements. Admittance spectrum was measured by using HP4194A Impedance/Gain phase analyzer. Displacement and generative force characteristics of the transducers were tested by using a LVDT sensor. Experimental and calculated results matched quite well. Device diameter and cavity diameter has strong effect on cymbal transducer characteristic. Adjusting the dimensional parameters can extend potential application areas of cymbal transducer.     

Construction of Micro-Patterned Polymer Structures by Piezoelectric Inkjet Printing

It is not simple to accurately deposit minute quantities of polymeric materials by inkjet printing systems. High viscosity, nozzle clogging, agglomeration, precipitation, and uncontrollable drying patterns are serious problems which are frequently encountered in polymer inkjet printing. In this study, we investigated how inkjet printability of polymers correlates with the polymer ink formulations and inkjet process variables. After a systematic study with different variables, various patterns such as dots, cross stripes, and honeycombs were fabricated on flexible polyimide (PI) films and the pattern morphology and spatial distribution of the resulting polymer deposits after solvent drying were characterized.     

The effect of pre-annealing on the microstructure of (K,Na)NbO3 ceramics

The effects of pre-annealing on the microstructure development and piezoelectric properties for 0.95(K_0.5Na_0.5)NbO₃–0.05LiSbO₃ (0.95KNN–0.05LS) ceramics were investigated. The pre-annealing suppressed the abnormal grain growth in both the undoped and Mn-doped 0.95KNN–0.05LS ceramics. The pre-annealed samples possessed smaller abnormal grains, larger matrix grains, and a broader grain size distribution compared to the samples sintered without a pre-annealing step. The pre-annealed samples presented better dielectric and piezoelectric properties, a larger dielectric constant (ε_r) and electromechanical coupling factor (k_p), and a smaller dielectric loss factor (tan δ).     

大功率多层压电陶瓷变压器的新进展

利用新开发成的大功率压电陶瓷材料 ,研制成功了输出功率大于10W以上的大功率多层压电陶瓷变压器 ,其输出效率大于94 % ,升压比为25～30     

Tribological property investigation on a novel pneumatic actuator with integrated piezo actuators

Pneumatic piston–cylinder actuators are commonly used in industry for a variety of automation and robotics applications. In order to suppress leakage, these actuators comprise seal rings which unfortunately introduce friction and affect the positioning accuracy and output force. This article investigates vibrations of the seal generated by integrated piezo actuators to reduce friction force. For this, two piezoelectric stacks are integrated in the cylinder and used to excite vibration modes. This concept was studied in a compact cylinder pneumatic actuator with a bore diameter of 5 mm and a stroke of 10 mm. Dry friction measurement shows a 52% reduction from the original friction force at a driving frequency of 18.29 kHz and vibration amplitude of 0.05 μm. In the wet friction experiments, the friction force can be reduced by 54% from the original wet friction with vibrations at amplitude of 0.04 μm.     

Improving the thickness accuracy of cold rolled narrow strip by piezoelectric roll gap control at high rolling speed

Particularly in fast rolling mills, conventional actuators reach their dynamic limits, when longitudinal thickness variations of the incoming strip shall be reduced with high accuracy by model-predictive roll gap control. Accordingly, the applicability of highly dynamic piezoelectric actuators in combination with electromechanical spindles and a high frequency precision measurement of the thickness in front of the roll gap was examined. Rolling tests in a cold rolling mill for narrow slit strips show that this novel concept is suitable to provide the required dynamic actuation especially at high rolling speed.     

RESEARCH ON THE DYNAMIC PROPERTY OF PIEZOELECTRIC MICRO DISPLACEMENT ACTUATOR FOR BORING ERROR COMPENSATION

The dynamic property of piezoelectric micro displacement actuator (PMDA) is analyzed, especially the mechanical characteristic, lag phase property and hysteresis phenomenon. The influence factors of static and dynamic mechanical characteristics and the lag phase property are analyzed systematically. Three main influence factors of lag phase property are discovered. With comparison to mechanical Coulomb friction, a generalized model of nonlinear hysteresis of PMDA is advanced, based on the essential analysis of nonlinear phenomenon. Finally the application of PMDA in error compensation control system of boring is introduced. A good compensation result is achieved.     

A Novel Quarter-Circular Arc Multi-Direction Piezo electric VEH and Its Theoretical Model

A quarter-circular arc piezoelectric Vibra-tion energy harvester (VEH) based on nonlinear geometry is proposed with both bending moment and torque deformation mode, so it can effectively absorb multi-directional vibration at the same resonance frequency. The theoretical model of quarter-circular arc piezoelectric VEH is established to study the resonance frequency and the output voltage. In order to demonstrate multi-directional performance of the quarter-circular arc VEH, the stress distribution is compared with that of the traditional piezoelectric VEH in multi-direction vibration, and the output voltage of the circular arc piezoelectric VEH are relatively increased 267.26％ in X-direction, 463.18％ in Y-direction, and 17.24％ in Z-direction. The external load is equipped in circuit to measure output power, whose matching resistance is around 21k?, and the maximum output powers are 7.57mW in X-direction, 2.39mW in Y-direction, and 9.93mW in Z-direction.