• Electrical & Electronic Materials
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• v.5 no.3
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• pp.295-301
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• 1992

본 연구는 고분자 압전 재료인 PVDF 필름을 시료로 사용하고 분극 조건을 변화시켜 가며 분극화 시킨후 압전계수를 측정하였다. 또한 X-선 회절 장치와 DSC 장치를 이용하여 결정구조 변화를 조사하였으며 또한 분극에 의해 생성된 결정의 용융특성도 관찰하였다. 분극되지 않은 시료의 용융 온도는 약 175.deg.C 부근에서 나타났으나 분극된 시료는 분극 전압이 증가함에 따라 184.deg.C부근에서 새로운 용융점이 나타나기 시작하였으며 분극 전압이 증가할수록 새로운 용융점이 점차 뚜렷해졌다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.288-289
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• 2011

압전 효과에 기초한 셀룰로오스 압전 종이의 진동센서 응용 가능성을 알아보았다. EAPap (Electroactive paper)은 재생과정과 테입 캐스팅을 이용해 만들었으며, 얇은 적층 필름을 이용해 코팅하였다. EAPap 샘플을 알루미늄 외팔보에 부착하여 진동 실험을 수행하였다. EAPap 센서의 출력을 비교하기 위해 가속도계를 이용하여 보의 응답 특성을 동시에 측정하였으며, 유한요소법을 이용해 보의 동특성을 구하여 비교하였다. EAPap 센서는 주위 환경 노이즈의 영향을 많이 받았는데, 접지와 절연을 통해 이러한 노이즈의 영향을 많이 감소시킬 수 있었으며, 실험결과로부터 EAPap의 진동센서 응용 가능성을 확인하였다.

• Proceedings of the Korean Fiber Society Conference
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• 1991.06a
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• pp.30-31
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• 1991

• 기계와재료
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• v.18 no.4 s.70
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• pp.21-38
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• 2006

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.6
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• pp.1371-1381
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• 1995

A novel hybrid control scheme to actively control the endpoint position of a very flexible single-link manipulator is proposed. The control scheme consists of a motor mounted at the beam hub and a piezofilm actuator bonded to the surface of the flexible link. The control torque of the motor to produce a desired motion is firstly determined by employing the sliding mode control theory on the equation of motion of the rigid link having the same mass as that of the proposed flexible link. The torque is then applied to the flexible manipulator in order to activate the commanded motion. During the motion, undesirable oscillation is actively suppressed by applying a feedback control voltage to the piezofilm actuator. Consequently, the imposed desired position is accomplished. In order to demonstrate high control performances accrued from the proposed method, computer simulations are undertaken by treating both regulating and tracking control problems.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.515-518
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• 2004

파라메트릭 라우드스피커(parametric loudspeaker)는 초음파의 지향성 발생 특성과 발생된 초음파의 비선형 전파 현상을 이용하여 간접적으로 가청음을 발생시키는 기술을 이용한다. 이를 이용하면 소리를 직진 형태로 전파 시킬 수 있기 때문에 원하는 영역에만 음향 신호를 전달할 수 있다. 본 연구에서는 파라메트릭 라우드스피커의 연구 진행 상황을 간략히 살펴보고, 현재 이 분야에서 가장 실용적인 초음파 발생기 방식으로 알려진 압전 필름형 초음파 발생기의 디자인 기술과 이를 적용한 파라메트릭 라우드스피커에 관하여 논한다. 그리고 이러한 스피커 시스템이 실용화되기 위해 해결해야 하는 문제점을 살펴본다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1498-1507
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• 1996

This paper presents a robust control of a smart flexible structure featured by a piezofilm actuator characterizing its light weght and quick response time. A mathematical governing equation for the proposed structure is derived by employing Hamilton's principle and a state space control model is subsequentrly obtained through modal analysis. Uncertain system parameters such as frequency variation are included in the control model. A sliding mode control theroy thich has inherent robustness to systme uncertainties is adopted to design a tracking controller for the peizofilm actuator. Using the output informaiton from the tip deflection sensor, a full-order observer is constructed ot estimate state variables for the system. Tracking performances for desired trajectories of sinusoidal amd step functions are evaluated by undertaking both simulation and experimental works.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.239-247
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• 2005

This paper deals with the development of a contact-type counting device using a piezoelectric polymer film as a sensor. The piezoelectric and vibration characteristics of the film under a bending vibration were investigated theoretically and experimentally. A counting device, which includes filters, an amplifier, an analog-digital converter, and a display, was designed and fabricated. The performance of the piezoelectric polymer sensor was evaluated in the sense of the responses to contact force, contact frequency, and contact speed. The life and the temperature effect were also investigated for the piezoelectric film sensor.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.91-97
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• 2012

Recently, the performances of electrical and electronic devices are improving while the sizes are becoming smaller. As sound-generating systems, the two-dimensional speakers have been developed in place of conventional three-dimensional ones. Piezoelectric materials show the mechanical vibrations due to the voltage applied from outside the materials. The early film speakers had a limitations of output power in that it was not easy to make the conducting macromolecular films on the surfaces of the materials due to the internal chemical properties of materials. We have adopted the corona surface treatment in order to improve the output characteristics by increasing the adhesion of the coating material on to the surface of the center material of piezo film. The results showed the improvement of output power in the wider range of operating frequencies.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.9
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• pp.78-85
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• 2008

Piezoelectric materials have been investigated as vibration energy converters to power wireless devices or MEMS devices due to the recent low power requirements of such devices and the advancement in miniaturization technology. Piezoelectric power generation can be an alternative to the traditional power source-battery because of the presence of facile vibration sources in our environment and the potential elimination of the maintenance required for large volume batteries. This paper represents the new power source which supplies energy device node. This system, called "energy harvesting system", with piezo materials scavenges extra energy such as vibration and acceleration from the environment. Then it converts the mechanical energy scavenged to electrical energy for powering device This paper explains the properties of piezo material through theoretical analysis and experiments The developed system provides a solution to overcome the critical problem of making up wireless device networks.