• Smart Structures and Systems
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• 제20권6호
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• pp.729-737
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• 2017

Piezoelectric composite laminates are a powerful material system that offers vast options to improve structural behavior. Successful design of piezoelectric adaptive structures and testing of control laws call for highly accurate, reliable and numerically efficient numerical tools. This paper puts focus onto linear and geometrically nonlinear static and dynamic analysis of smart structures made of such a material system. For this purpose, highly efficient linear 3-node and 4-node finite shell elements are proposed. Both elements employ the Mindlin-Reissner kinematics. The shear locking effect is treated by the discrete shear gap (DSG) technique with the 3-node element and by the assumed natural strain (ANS) approach with the 4-node element. Geometrically nonlinear effects are considered using the co-rotational approach. Static and dynamic examples involving actuator and sensor function of piezoelectric layers are considered.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2392-2394
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• 2005

This paper presents a tuneable bandstop resonator with two possible configurations, it can be used to tune its center frequency, or it can be used to tune its bandwidth. The tuneable bandstop resonator has potential application in microwave communications receivers, where it can be used to tune out interfering signals. The proposed resonator is comb actuated, where the resonator's displacement produces different values of frequency or bandwidth, this is achieved by decoupling electromagnetic energy from a main transmission line. The proposed fabrication process for the resonator is by anodic bonding pyrex glass and tow resistivity silicon, where the comb resonator structure is patterned by deep reactive ion etching (DRIE). This paper presents the resonator and actuator design in both configurations, as well as the fabrication process intended for its development.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.804-806
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• 2003

In these days the Vacuum Circuit Breaker(VCB) is used in most medium voltage level because VCB has merits of simple structure, long life, free maintenance and environment friendly characteristics. Most of VCBs adopt mechanical spring drive mechanism to operate vacuum interrupter, but this mechanism is composed of many components and needs frequent maintenance works. In this paper, we study about the VCB drive mechanism with Permanent Magnet Actuator (PMA). Design methods and design flows about PMA are presented. The magnetic equivalent circuit is used for elementary and detailed design to determine the size of PMA. Finite Element Method (FEM) analysis is performed to evaluate the behavior characteristics of PMA in both static and transient state. Finally we manufacture sample PMA and verify FEM analysis through experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.15-18
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• 1996

In the case of need for reciprocating motion, the study for application of Linear Oscillating Actuator(LOA) is being accomplished. LOA is the simpler and more efficient than other linear apparatus using the rotary motor because LOA produce the thrust force without any converter such as cam, clutch, rack, pinion and belt, etc. We designed the flat moving core type LOA and manufactured for trial. This paper shows the structure and dynamic characteristics of LOA.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1189-1196
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• 2001

When fluid flows at high speed over an open cavity, large acousitc pressure is produced by fluid/structure interaction at the downstream edge of the cavity. The goal of this paper is suggestion of effective control method to suppress the noise generated from cavity and numerically simulation of active control. The cavity instability mechanism is simulated and a close-loop control algorithm is implemented. The effects of the actuator and some control function are discussed. The compressible Navier-Stokes equations are solved with the high-order and high-resolution numerical schemes to precisely simulate the interaction between flow and acoustic. The results show that noise is effectively suppressed with the control method suggested in this paper.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.674-679
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• 2000

This research is concerned with the modeling technique and active vibration controller design for slewing smart structures. When cantilever beam rotates about axes perpendicular to the undeformed beam's longitudinal axis, it experiences inertial loading. Hence, the beam vibrates from the initial stage of slewing, In this paper, the analytical model for a single slewing flexible beam with surface bonded piezoelectric sensor and actuator is developed using the Hamilton's principle with discretization by the assumed mode method. It is found from experiments that the theoretical model lacks the frictional effect. The frictional effect is incorporated into the equations of motion by employing the coupling factor. Theoretical and experimental results show problems arising in modeling and controller design.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.249-255
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• 2000

The design and test of an magnetostrictive linear motor(MLM) that operates based on self-moving cell concept is presented. The moving cell is composed of Terfenol-D linear actuator and a ring structure, and a cell train is constructed by connecting two cells in series. Since this motor uses the stroke of Terfenol-D actuators and friction force of the cells, it can essentially produce long stroke and large force. The overall performance of the MLM was measured in terms of speed and force. The pushing force is directly related with the friction force. This work is a proof-of-concept stage and investigation is necessary for realistic application.

• Smart Structures and Systems
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• 제16권1호
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• pp.27-46
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• 2015

Active surface adjustment of cable net structures is becoming significant when large-size cable net structures are widely applied in various fields, especially in satellite antennas. A general-duty adjustment method based on active cables is proposed to achieve active surface adjustment or surface profile reconfiguration of cable net structures. Piezoelectric actuators and voice coil actuators are selected for constructing active cable structures and their simplified mechanical models are proposed. A bilevel optimization model of active surface adjustment is proposed based on the nonlinear static model established by the direct stiffness method. A pattern search algorithm combined with the trust region method is developed to solve this optimization problem. Numerical examples of a parabolic cable net reflector are analyzed and different distribution types of active cables are compared.

• Advances in robotics research
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• 제1권1호
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• pp.1-19
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• 2014

Microgripper is an essential device in the micro-operation system. It can convert other types of energy into mechanical energy and produce clamp movement with required chucking force, which enables it a broad application prospect in the domain of tiny components' processing and assembly, biomedicine and optics, etc. The performance of a microgripper is dependent on its power supply, type of drive, mechanism structure, sensing components, and controller. This paper presents a state-of-the-art survey of recent development on flexure-based microgrippers. According to the drive type, the existing microgrippers can be mainly classified as electrostatic microgripper, electrothermal microgripper, electromagnetic microgripper, piezoelectric microgripper, and shape memory alloy microgripper. Additionally, some different mechanisms, sensors, and control methods that are used in microgripper system are reviewed. The key issue of how to choose those components in microgripper system design is also addressed.

• 로봇학회논문지
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• 제14권3호
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• pp.186-190
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• 2019

When problems occurred in the unstable and/or extreme terrain environment, formal field-driving robots were unable to provide any other options such as the transformation of the wheel and body structure, and so on. For such reason, this paper proposed a novel type of integrated wheel mechanism that can be operated as a conventional driving wheel mode and hybrid wheel-leg mode in order to be negotiated in an unstable terrain environment. The mechanical effect of the proposed variable wheel mechanism was analyzed considering the geometric constraint and power requirement of the actuator for the transformation. In addition, we designed and manufactured the prototype of field-driving robot, which reliably control the variable wheel shape. Finally, the effectiveness of the variable wheel mechanism was verified by preliminary experimental approach.