• 센서학회지
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• 제29권5호
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• pp.312-322
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• 2020

As the use of mobile devices increase, there is public interest in the utilization of the human motion generated mechanical energy. The human motion generated mechanical energies vary depending on the body region, type of motion, etc., and an appropriate device has to be designed to utilize them effectively. In this work, a device based on the principles of triboelectric generation and inertia was assessed in order to utilize the multi-axial mechanical energies generated by human motions. To improve the output performance we confirm the changes in the output that vary with the structural design, the reasons for such changes, and variations in performance based on the parts of the human body. In addition, the level of electrical energy generated based on motion type was measured; a maximum voltage of 30 V and a current of 2 ㎂ were generated. Finally, the proposed device was utilized in LEDs used for lighting, thus demonstrating that multi-axial mechanical energies can be harvested effectively. Based on the results, we expect that the developed device can be utilized as a sensor to detect mechanical energies, to sense changes in motion, or as a generator for auxiliary power supply for mobile devices.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.99-100
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• 2021

In this study, the setting times of concrete was evaluated using the electro-mechanical (EMI) behavior of piezoelectric sensor embedded in the concrete. Penetration resistance test was also performed to compare with EMI sensing technique. As a result, the setting times of concrete can be measured more effectively than penetration resistance test through the EMI sensing technique using the piezoelectric sensor.

• 대한기계학회논문집A
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• 제20권3호
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• pp.891-900
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• 1996

The vision sensor which is based on the optical triangulation theory with the laser as an auxiliary light source can detect not only the seam position but the shape of seam. In this study, a vision sensor using the scanning laser beam was investigated. To design the vision sensor which considers the reflectivity of the sensing object and satisfies the desired resolution and measuring range, the equation of the focused laser beam which has a Gaussian irradiance profile was firstly formulated, Secondly, the image formaing sequence, and thirdly the relation between the displacement in the measuring surface and the displacement in the camera plane was formulated. Therefore, the focused beam diameter in the measuring range could be determined and the influence of the relative location between the laser and camera plane could be estimated. The measuring range and the resolution of the vision sensor which was based on the Scheimpflug's condition could also be calculated. From the results mentioned above a vision sensor was developed, and an adequate calibration technique was proposed. The image processing algorithm which and recognize the center of joint and its shape informaitons was investigated. Using the developed vision sensor and image processing algorithm, the shape informations was investigated. Using the developed vision sensor and image processing algorithm, the shape informations of the vee-, butt- and lap joint were extracted.

• 대한기계학회논문집A
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• 제41권3호
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• pp.187-192
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• 2017

본 논문에서는 탄소나노튜브 전왜성 복합소재(Nano-Carbon Piezoresistive Composite, NCPC)를 기반으로 하며, 3D 프린팅 공정을 활용하여 제작된 압력센서의 개발 진행 연구를 소개하였다. 압력센서의 성능을 향상시키기 위하여 센서전극을 외팔보 형태로 설계하였고 3D 프린팅 공정을 활용하여 소형전극을 제작하였다. 압력을 전기적 저항의 변화로 바꾸는 전왜성 센서의 전극은 2wt%의 다중벽 탄소나노튜브/에폭시 전왜성 복합소재로 제작하였다. 센서는 압력시스템에 용이하게 적용하기 위하여 파이프 플러그 캡에 삽입하여 제작을 하였으며, 실험실 환경에서 압력교정기를 활용하여 실험을 하였다. 외팔보 전극의 압력센서는 16,500kPa까지 선형적인 출력전압 특성을 보였으며, 이는 벌크형 전극의 압력센서 대비 약 200% 압력측정 성능 향상을 보였다.

• 대한기계학회논문집
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• 제17권9호
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• pp.2381-2389
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• 1993

In this paper the design and test results of a dynamic flow rate sensor was reported. This sensor comprises an 2-way cartridge valve as standard hydraulic component and a displacement sensor. Its working principle bases on the linear relationship between the flow rate and the piston displacement of 2-way cartridge valves under constant pressure drop. This principle is well known, however it is not easy to develop a flow rate sensor with the measurement range of 300 1/min, pressure loss of less than 8 bar at 300 1/min, maximum linearity error of less than $\pm$1% and the maximum rising time of 10 ms. This paper describes the design procedure of the flow rate sensor, the improvement procedure of static performance and test method and results of dynamic performance.

• 센서학회지
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• 제26권3호
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• pp.168-172
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• 2017

A nondispersive infrared (NDIR) ethanol gas sensor was prototyped with ASIC implemented thermopile sensor, which included a temperature sensor and two ellipsoidal waveguide structures. The temperature dependency of the two ethanol sensors (with partially blocked and intact structures) has been characterized. The two ethanol gas sensors showed linear output voltages initially when varying the ambient temperature from 253 K to 333 K. The slope of the temperature sensor presented a constant value of 15 mV/K. After temperature compensation, the ethanol gas sensor estimated ethanol concentrations with larger errors of 20 to 25% below 200 ppm. However, the estimation errors were reduced to between -10 and +1 % from 253 K to 333 K above 200 ppm ethanol gas concentration in this research.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.121-126
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• 2005

This paper describes the attributes, performance and development status of a high performance capacitive torque sensor intended for use in a electric power steering (EPS) system. The EPS system is composed of torque sensor, ECU, motor, gears and etc. Among the elements, torque sensor in the steering column is one of the core technologies. The new capacitive torque sensor in this paper is developed differently from working principle and mechanical structure compare to extant torque sensors in market and patent. Based on the result of numerical analysis, a experimental equipment is made which is composed of a test jig and a capacitive sensor and validity of numerical analysis and feasibility of the torque sensor are verified.

• Smart Structures and Systems
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• 제1권2호
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• pp.121-140
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• 2005

This paper presents a systematic investigation of the effect of sensor location on the data quality and subsequently, on the effectiveness of machine health monitoring. Based on an analysis of the signal propagation process from the defect location to the sensor, numerical simulations using finite element modeling were conducted on a bearing test bed to determine the signal strength at several representative sensor locations. The results showed that placing sensors closely to the machine component being monitored is critical to achieving high signal-to-noise ratio, thus improving the data quality. Using millimeter-sized piezoceramic plates, the obtained results were evaluated experimentally. A comparison with a set of commercial vibration sensors verified the developed structural dynamics-based sensor placement strategy. It further demonstrated that the proposed shock wave-based sensing technique provided an effective alternative to vibration measurement, while requiring less space for sensor installation.

• 한국정밀공학회지
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• 제33권4호
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• pp.303-307
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• 2016

The fiber optical temperature sensing device was developed by using a Fiber Bragg Grading (FBG) sensor and a linear transmittance optical filter. The temperature change causes change in the FBG sensor reflectance wavelength and the reflectance wavelength from FBG sensor is transmitted to a linear transmittance filter so that the optical signal value is determined by the wavelength. The temperature can be measured by the optical signal value by passing FBG reflectance wavelength to the linear transmittance filter. Using the developed system, temperature ranges from $10^{\circ}C$ to $50^{\circ}C$ were measured and the measured data were almost linear.

• 대한기계학회논문집A
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• 제39권1호
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• pp.37-43
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• 2015

압전소자(Piezoelectric transducer, PZT)는 구조물의 안정성 평가를 목적으로 하는 구조 건전성 모니터링 기법(Structural Health Monitoring, SHM)의 센서(sensor) 및 구동기(actuator)로 많이 활용되고 있다. 사용되는 센서 및 구동기의 성능을 사전에 파악하고, 잔존수명 및 결함을 탐지하는 센서 자가 진단법은 안정적인 SHM의 결과를 얻기 위해 매우 중요한 절차이다. 본 연구에서는 Admittance 값을 기반으로 한 센서 자가 진단절차를 통하여 압전체 센서의 결함을 탐지하였으며, 센서 진단과정에 영향을 줄 수 있는 접합층 및 온도 등의 영향인자에 대해 실험적 분석을 실시하였다. 분석 결과 Admittance와 온도 및 접착제의 상관관계를 파악할 수 있었으며, admittance를 기반으로 한 센서 자가 진단 절차를 통해 센서의 접착상태와 접착제의 성능평가가 가능함을 검증하였다.