• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1413-1418
• /
• 2003

In this study, the topology optimization is applied to the design of a piezoelectric microactuator satisfying the specific mean transduction ratio(MTR). The optimization problem is formulated to minimize the difference between the specified and the current mean transduction ratio. In order to analyze the response of the piezoelectric-structure coupled system, both the structural and the electric potential are considered in the finite element method. The optimization problem is resolved by using Sequential Linear Programming(SLP) and the results of test problems show that the design of a piezoelectric microactuator with specified mean transduction ratio can be obtained.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.2
• /
• pp.206-213
• /
• 2004

In this study, the topology optimization is applied to the design of a piezoelectric microactuator satisfying the specific mean transduction ratio(MTR). The optimization problem is formulated to minimize the difference between the specified and the current mean transduction ratio. In order to analyze the response of the piezoelectric-structure coupled system, both the structural and the electric potential are considered in the finite element method. The optimization problem is resolved by using Sequential Linear Programming(SLP) and the results of test problems show that the design of a piezoelectric microactuator with the specified mean transduction ratio can be obtained.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.173-173
• /
• 2000

This paper discusses a observer based discrete-time controller design and presents a modified control structure for dual-stage hard disk drive systems using piezoelectric microactuator(MA). In plant modeling, dynamic coupling between VCM and MA is not considered. Each controller is organized independently and designed using pole placement. Simulation result shows that 4th-order controller achieves about 3kHz servo bandwidth and 0.22msec of 2% settling time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.11a
• /
• pp.232-236
• /
• 2000

To provide model parameters for servo control system design, dynamic characteristics of a piezoelectric microactuator for hard disk drive(HDD) were investigated. At first frequency response characteristics was measured and a second order model was proposed. Here the amplitude dependent dynamic characteristics such as low frequency gain and damping ratio were studied. In addition, the load current and equivalent impedance of the piezoelectric actuator were measured by varying excitation voltage and frequency. At last, the super-harmonic resonance of the piezoelectric actuator was discussed.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.49 no.9
• /
• pp.495-501
• /
• 2000

This paper presents a method to minimize the initial deflection of a multi-layer piezoelectric microactuator without loosing its piezoelectric deflection performance required for light modulating micromirror devices. The multi-layer piezoelectric actuator composed of PZT silicon nitride and platinum layers deflects or buckles due to the gradient of residual stress. Based on the structural analysis results and relationship between process conditions and mechanical properties we have modified the fabrication process and the thickness of thin film layers to reduce the initial residual stress deflection without decreasing its piezoelectric deflection performance. The modified designs fabricated by surface-micromachining process achieved the 77% reduction of the initial deflection compared with that of the conventional method based on the measured micromechanical material properties is applicable to the design refinement of multi-layer MEMS devices and micromechanical structures.

• Steel and Composite Structures
• /
• v.41 no.6
• /
• pp.805-820
• /
• 2021

In this research, the buckling and free vibration of three-phase carbon nanotubes/ fiber/ polymer piezoelectric nanocomposite face sheet sandwich microbeam with microsensor and micro-actuator surrounded in elastic foundation based on modified couple stress theory (MCST) is investigated. Three types of porous materials are considered for sandwich core. Higher order (Reddy) and sinusoidal shear deformation beam theories are employed for the displacement fields. Sinusoidal surface stress effects are extracted for sinusoidal shear deformation beam theory. The equations of motion are derived by Hamilton's principle and then the natural frequency and critical buckling load are obtained by Navier's type solution. The determined results are in good agreement with other literatures. The detailed numerical investigation for various parameters is performed for this microsensor-microactuator. The results reveal that the microsensor-microactuator enhanced by increasing of Skempton coefficient, carbon nanotubes diameter length to thickness ratio, small scale factor, elastic foundation, surface stress constants and reduction in porous coefficient, micro-actuator voltage and CNT weight fraction. The valuable results can be expedient for micro-electro-mechanical (MEMS) and nano-electro-mechanical (NEMS) systems.

• Proceedings of the KIEE Conference
• /
• 1989.07a
• /
• pp.345-348
• /
• 1989

A small linear incremental device, which is called a microworm, is introduced, and this paper explains working principle, design considerations and theoritcal force analysis of the microworm. A fluid control microvalve and a piezoelectric motor as an application of the microworm are explored for feasibility.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.25 no.12
• /
• pp.2002-2008
• /
• 2001

Nonlinear vibration characteristics of a piezoelectric-type micro actuator used for hard disk drives are experimentally studied. The nonlinear characterisitics include hysteresis, superharmonic resonance, jump phenomenon, and shifting of natural frequencies. The vibration modes and frequencies of the commercial actuator of the Hutchinson's Magnum series are measured using a laser vibrometer. From harmonic excitation to the PZT acturator, we observe interesting hysteresis patterns with 3 times input frequency. It is shown that the micro actuator has the typical 3 times superhamonic resonances coupled to the first torsional and sway modes of the suspension.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.4 no.4
• /
• pp.39-47
• /
• 2005

In this paper, a novel high power micropump using active check valves in place of conventional passive check valves employed at the inlet and outlet ports is presented. It actively controls open/close motion of check valves using piezoelectric actuator for expansion/contraction of pump chamber. A prototype micropump having an effective size of $17mm{\times}8mm{\times}11mm$ is fabricated. Frequency-dependent flow rate characteristics, bi-directional flow characteristics and load characteristics are experimentally investigated using a timing control method for valve closing motion. From the obtained experimental results, it is ascertained that optimal values of the phase shift compared to the voltage to drive pump chamber are $15^{\circ}$ for inlet check valve and $195^{\circ}$ for outlet. Based on the obtained results, a sheet-type active shuttle valve that has a unified valve-body for inlet and outlet check valves is proposed. A micropump with an effective size of $10mm{\times}10mm{\times}10mm$ is fabricated and the basic characteristics are experimentally investigated.