Papers by Keyword: LIPCA

Abstract: In this study, a high performance peristaltic micropump has been developed and investigated. The micropump has three cylinder chambers which are connected through microchannels and two normally closing active membrane valves at inlet/outlet for high pumping pressure performance. A circular shaped miniature LIPCA has been developed and manufactured for actuating diaphragms. In this LIPCA, a 0.1mm thickness PZT ceramic is used as an active layer. As a result, the actuator has shown to produce large out-of-plane deflection and consumed low power. During the design process, a coupled field analysis was conducted to predict the actuating behavior of a diaphragm. The actuator behavior was investigated both theoretically and experimentally. In addition, MEMS technique was used to fabricate the peristaltic micropump. Judging from experimental flow rate and pumping pressure results, the present peristaltic micropump has higher performance than the same kind of micropump developed elsewhere.

Abstract: In this paper, the pumping performance of a piezoelectric micropump is simulated with commercial finite element analysis (FEA) software COMSOL Multiphysics 3.2a. The micropump is composed of a 4-layer piezo-composite actuator (LIPCA), a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, structural domain and fluid domain are coupled in the simulation. Water flow rates are numerically predicted for geometric parameters of the micropump. Based on this study, the micropump is optimally designed to obtain its better pumping performance.

Abstract: The applicable bending moment equation of LIPCA is necessary even though the fiber layer ply orientation is changed. The aim of this research is to evaluate the relationship between the total effective moment (ME) and Bernoulli-Euler bending moment (M) when the ply orientations of unidirectional CFRP, which is one of the various laminate configurations in LIPCA, are changed. Since the related previous equation between the performance stroke range (h) and the radius of curvature (ρ) was just applicable to the CFRP ply orientation [0], it will be modified using these results. The related modified equation, which has nothing to do with the various CFRP ply orientation, is also suggested and compared with the previous equation.

Abstract: This paper presents a mechanical design of biomimetic fish robot using the Lightweight Piezo-Composite Actuator (LIPCA). We have designed a mechanism for converting actuation of the LIPCA into caudal fin movement. The linkage mechanism consists of rack-pinion and four-bar linkage systems. Two kinds of caudal fins are fabricated such that the shapes resemble subcarangiform and ostraciiform caudal fin shape, respectively, and then attached to the linkage system. The swimming test using 300 Vpp input with 1 Hz to 3 Hz frequency was conducted to investigate the effect of tail beat frequency and shape of caudal fin on the swimming speed. The maximum swimming speed was reached when the device was operated at its natural swimming frequency. At the natural swimming frequency of 1.016 Hz, maximum swimming speeds were 1.267 cm/s and 1.041 cm/s for ostraciiform and subcarangiform caudal fin, respectively. The Strouhal numbers, which are a measure of thrust efficiency, were also calculated in order to examine thrust performance of the present biomimetic fish robot.

Abstract: Research on piezoelectric unimorph actuators has been intensively increased during the past decade due to the wide applications of this actuator type in aerospace, vibration control, biomimetic robots, artificial muscles… Most analyses focused on the design performance with load-free actuating condition. Loading performance has not been considered adequately yet though in real application the actuators always work under certain carrying load. This paper introduces the measuring system, the experimental setup and presents the observed loading performance of the actuators with center load. Two typical kinds of piezoelectric unimorph actuator, LIPCA-C3 and THUNDER, are investigated. The numerical analyses are also conducted to illustrate the loading behavior of these devices. Some remarks and suggestions for future research activities are drawn.

Abstract: In this work, behavior of a unimorph piezoceramic actuator, LIPCA (Lightweight Piezo- Composite Actuator) has been numerically and experimentally investigated. By measuring the lateral displacement created by the compressive load, the buckling load of the LIPCA was determined. Under simply supported configuration, the measured buckling load agreed well with the geometrically nonlinear buckling load from the finite element analysis. The measured data shows that the lateral displacement of the LIPCA is significantly increased when the electric field is prescribed to the LIPCA in addition to the compressive load. The measured data was compared with the computed results from the geometrically nonlinear finite element analysis. The numerical simulation agreed well with the measurement for low compressive load and low electric field.

Abstract: This paper presents a design and performance evaluation of a valveless micropump fabricated from polydimethylsiloxane (PDMS) based on molding techniques. A circular lightweight piezo-composite actuator (LIPCA) was successfully developed for the actuating diaphragm of the micropump. The LIPCA is a composite actuator designed and fabricated with piezoceramics in combination with carbon fabric and glass epoxy. Numerical and experimental methods were used to investigate the performance of the circular LIPCA. The LIPCA was glued to a PDMS membrane to form the diaphragm of the micropump. The diaphragm has several advantages, such as high displacement, dome-shaped deformation and geometrically independent actuation profile. The diaphragm based on a LIPCA 9 mm in diameter produces a deflection of 27 μm at the applied voltage of ± 200 V and a frequency of 1 Hz. The micropump has a maximum water flow rate of 0.95 ml/min and a maximum backpressure of 3.8 kPa. The merits of the present micropump are low cost, ease of manufacturing and high level of effectiveness. The proposed LIPCA is proven to be a promising alternative to the conventional piezoelectric actuator used in micropumps.

Abstract: This paper addresses detail design and demonstration of an insect-mimicking flappingwing mechanism composed of LIPCA (Lightweight Piezo-Composite Actuator) and linkage system that can amplify the actuation displacement of LIPCA. The angular amplification of the linkage system can provide various flapping angles by adjusting the actuation point of the LIPCA. The device can generate flapping frequency ranging from 5 to 50 Hz depending on weight of the wing and linkages. Flapping tests using different wing mass, area, and aspect ratio were performed to investigate the flapping performance. The test results were described and compared with the estimation. It was found that changes in wing mass, area, and aspect ratio result in significant variation of natural flapping-frequency.