Papers by Keyword: Actuator

Abstract: The advantages of micromachining over conventional fabrication include precise dimensional control, integration of on-chip circuits and potential low cost owning to batch processing. Fabrication microspeaker for hearing instrument application using MEMS technology is challenging because of certain critical requirements, including their small size, low driving voltage, high output sound pressure level, flat frequency response and low energy consumption. A small in size, lightweight, and low cost microspeaker is demanded for application such as cellular phones and hearing aids. The device consist of two part; first parts is a micromachined polyimide membrane as the sound generating plate, where thevoice coil placed on the top of membrane, and the coil is a single loop voice coil. The second part is back plate permanent magnet. The disc permanent magnet bonded on acoustic hole plate is Neodymium-Iron-Boron (NdFeB) with magnetization of 1.45 T, diameter 1.6 mm, and thickness 0.8 mm. The fabrication process and performance of the first result device is discussed, and the thickness of electroplated single loop voice coil copper 10 mm and acoustic hole bonded together. The total size of the microspeaker chip is 5 mm x 5 mm x 1.5 mm, polyimide membrane thickness 2 mm.

Abstract: This paper proposes a noncontact magnetic suspension of an iron ball using a flux path control mechanism. In this system, the suspension force is generated by a disk-type permanent magnet, and controlled by varying the angle of the permanent magnet that is driven by a rotary actuator. In this paper, first, the suspension principle is explained, and the prototype is introduced. Second, the characteristics of this system are examined by some basic experimental results. Third, a model is created, and the numerical simulation is carried out. Finally, the suspension experiments are succeeded using the prototype, and the results are shown and discussed.

Abstract: As a novel functional composite material, orthotropic piezoelectric composite material has been developed into various transducers used in the non-destructive technology and the structural health monitoring in aviation engineering, mechanical engineering, and civil engineering. In this study, the configuration and the mechanics-electric coupling property were described. A concept of the orthotropic ratio was proposed to derive the optimal length-to-width ratio of an actuator made of the orthotropic piezoelectric composite material. From the optimal length-to-width ratio, an optimal design method of the type 1-1 actuator, made of the orthotropic piezoelectric composite material, was advised. The mechanics-electric property of the type 1-1 actuator of orthotropic piezoelectric composite material designed by this approach was simulated with the software COMSOL under different actuating voltages. The modeling results were validated by experiments. It was evident that the results of numerical simulation were good agreement with that of experiments.

Abstract: In this paper, the different applications of piezoelectric material (PZT) are surveyed such as: actuators, motors, transformers, sensors, and benders. The operation concept, advantages and disadvantages of these types are explained, that drive the suitable application of them. Moreover, the electrical and mechanical features of piezoelectric material are presented. These features are dynamic behavior, operation voltage, maximum force, and temperature effect. There are different piezoelectric material types such as ferroelectric materials and ferroelectric polymers that are presented and a comparison between them is achieved.

Abstract: Mathematical models predicting the behaviour of IMPCs (Ionic Polymer-Metal Composites ) were built and their validity was verified computationally as well as experimentally. A transfer function associating the applied input voltage with the IPMC tip displacement was derived based on results obtained by vibration analysis. Employing the derived transfer function, three mathematical models, based on feed forward, feedback and two-degree-of-freedom models, were formulated. Computational and experimental verification of these models revealed that the feedback and two-degree-of-freedom models were capable of high performance in controlling the bending of an IPMC.

Abstract: A coupled system of a magnet and magnetic fluid is used as a piston in a U-tube. Applying reciprocating travelling magnetic field produces reciprocating motion of the coupled system. In this study, vibration properties of the coupled system are investigated experimentally. Three types of vibration mode of the coupled system appear and the mode depends on the frequency and intensity of travelling magnetic field and the shape of the magnet. Basically the coupled system follows the travelling magnetic field in the range of low frequency, while the system cannot follow the travelling field when the frequency of the travelling magnetic field is high. However, when the magnet is sphere or short cylinder, the other type of vibration appears in the range of low frequency and the coupled system intermittently tracks the travelling magnetic field.

Abstract: Prestrain affects the performance of dielectric elastomer actuators so much that rare actuators is used before pre-stretching. In this article, the author made a series of circular actuators with acrylic VHB4910 and graphite mixture electrodes, and performed contrast experiments, under non-prestrain, uniaxial prestrain and equibiaxial prestrain, respectively, to figure out the changing of area strain against prestrain. Result of experiment indicates that the film actuator obtains the highest output strain while applying equibiaxial prestrain. An optimum prestrain ratio of actuators, in this research, occurs between 150%~200% under equibiaxial prestrain condition. This result has practical value in the future design and use of dielectric elastomer actuators.

Abstract: A novel hybrid-electromagnetic actuator with the permanent magnet is designed, by which the operating component can realize the to-and-fro driving movement by changing the current direction of its control coil and it is more convenient to use for active vibration control. The electromagnetic force of the actuator is theoretically calculated by equivalent magnetic circuit and by the finite element respectively. Finally the characteristic of its rigidity and damping in an active vibration isolation system are analyzed, and it is indicated that they are not only related to its structure parameters，but also to the parameter of controller.

Abstract: After obtaining a way to fabricate IPMC actuator with palladium electrodes, the deformation of IPMC actuator behavior is evaluated under various solvents, various temperatures, and various frequencies of input voltages. By using the non-electrolytic plating method to obtain IPMC actuator, it is found that as the increase of the ionic radius the bending response of IPMC actuator becomes predominant from the experimental observation. When the electric field across its cross section is unloaded, IPMC actuator shows a large back relaxation under high temperature. In the experiment of the frequency response of the input voltage, IPMC actuator shows a good response to various frequencies from 0.1 to 6.0 Hz in which the resonant peak is observed at 5.5 Hz.

Abstract: A power actuator based on a great volume expansion on hydrogenation of hydrogen storage alloys (HSAs) has been developed. The actuator has a bimorph structure consisting of Pd-Ni alloy and Cu-plating to convert the volume change into bending motion. The techniques to control the bending and rotation motions of the actuator were investigated by adjusting alloy composition, shape and the amount of hydrogen absorbed in the HSA. It is found that Pd-Ni alloy actuators exhibit a cyclic bending motion on hydrogen absorption and desorption cycles and the bending behavior can be controlled by controlling the hydrogen pressure. When a ribbon shaped actuator was deformed into the “L” shape on the transverse section, a rotation motion was observed without modifying the basic bimorph structure of the actuator.