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Abstract: Optical disc drives (ODDs) such as CD, DVD and HD-DVD are cheaper and more distributable than solid-state memories and hard disc drives (HDDs). In the era of mobile environment, ultra-slim ODDs have been studied and developed to show the feasibility of mobile application. This paper is a study on miniaturization of an optical pickup actuator, one of key components for ultra-slim ODDs. A newly configured actuator which is targeted to be installed in 5mm height ODDs is presented in this work. In order to reduce the height of the optical pickup actuator, a novel structure of suspension is developed by arranging Ω-shaped plate-suspension at both sides of a moving part in same plane. Also, the reduction of unwanted resonance peak, which is one of main issues in optical pickup actuators, is attempted. The presented structure of suspension is optimized by finite element analysis in terms of linearity and damping characteristic that reduces the unwanted resonance such as the rolling, pitching modes. The electromagnetic circuits, which generate driving forces, are arranged for high sensitivity and the reduction of the unwanted resonances. Developed actuator is tested to confirm stable frequency response characteristics in focusing and tracking directions as well as low tilt characteristics. In addition, the actuator is mounted on a DVD pickup system and optical signal from this optical pickup is detected. This reveals the feasibility as an information storage for mobile devices. [Copyright &y& Elsevier]

Abstract: Several advanced technologies are introduced in automotive applications. Higher energy density and dynamic performance are demanding new and cost-effective actuator structures. Magnetostriction (MS), change in shape of materials under the influence of an external magnetic field, is one of the advanced technologies. Good understanding of specific design constrains is required to define and optimize a magnetostrictive actuator. This paper presents parametrical analysis with magnetic simulation of a magnetostrictive actuator. Proposed actuator has been designed, and the performance has been evaluated on experimental rig. Strain, elongation of the shaft, of 1000ppm at 10A and a blocked force over 4500N has been achieved with shaft of 8mm diameter, made of Terfenol-D. Furthermore, the effect of pre-stress of the Terfenol-D shaft has been evaluated experimentally. The study shows that excellent features can be obtained by magnetostrictive materials for many advanced applications. [Copyright &y& Elsevier]

Abstract: Nonlinear vibrations of piezoelectric/elastic/piezoelectric sandwich beams submitted to active control are studied in this paper. The proportional and derivative potential feedback controls via sensor and actuator layers are used. Harmonic balance method and the Galerkin procedure are adopted. A complex amplitude equation governed by two complex parameters is derived accounting for the geometric nonlinearity and piezoelectric effects. The nonlinear frequency and loss-factor amplitude relationships with respect to the gain parameters are obtained. The feedback effects are analyzed for small and large vibration amplitudes of sandwich beams. The frequency response curves are presented and discussed for various gain parameters. [Copyright &y& Elsevier]