• 대한전기학회논문지
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• 제39권4호
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• pp.386-392
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• 1990

This paper discribes a sonar-based certainty grid, the probabilistic representation of the uncertain and incomplete sensor knowledge, for autonomous mobile robot navigation. We use sonar sensor range data to build a map of the robot's surroundings. This range data provides information about the location of the objects which may exist in front of the sensor. From this information, we can compute the probability of being occupied and that of being empty for each cell. In this paper, a new method using Bayesian formula is introduced, which enables us to overcome some difficulties of the Ad-Hoc formula that has been the only way of updating the grids. This new formula can be applied to other kinds of sensors as well as sonar sensor. The validity of this formula in the real world is verified through simulation and experiment. This paper also shows that a wide angle sensor such as sonar sensor can be used effectively to identify the empty area, and the simultaneous use of multiple sensors and fusion in a certainty grid can improve the quality of the map.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.724-728
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• 2005

This paper represents a development of a range finder sensor module for indoor 2-D mapping and modified Hough transformation for map building. A range finder sensor module has been developed by using optic PSD (Position Sensitive Detector) sensor array at a low price. While PSD sensor is cost effective and light weighting, it has switching noise and white noise. To remove these noises, we propose a heuristic filter. For line-based map building, also we proposed advanced Hough transformation and navigation algorithm. Some experiments were illustrated for the validity of the developed system.

• 대한전자공학회논문지
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• 제25권3호
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• pp.307-314
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• 1988

The thin, square-diaphragm silicon pressure sensor utilizing shear piezoresistance effect was designed and fabricated and its characteristics were examined. The sensor has only one diffused resistor, whereas conventional full-bridge sensor has four. Sensitivity is somewhat lower but temperature compensation is easier than the latter. The proposed sensor was fabricated with only one p-type diffused resistor of the dimension of 113x85\ulcorner\ulcornerlocated near the center of the edge of the diaphragm. The resistor was at 45\ulcornerwith the edge of the diaphragm. The sensitivity of the sensor was 36\ulcorner/V\ulcornermHg and was linear in the pressure range from 0 to 300 mmHg. The temperature coefficient without temperature compensation was 55 ppm/\ulcorner and it was decreased to about 0.17 mmHg/\ulcorner with compensation in the range from 10 to 60\ulcorner.

• 조명전기설비학회논문지
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• 제25권8호
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• pp.99-105
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• 2011

This paper is about the design of 3-axis magnetic sensor module which detects parking and moving vehicle. For the sensor module, MR Sensor from Honeywell of which maximum measurement range is ${\pm}2$[G] is used. It also consisted of amplifier and sensor filter and fabricated $30{\times}50$[mm] PCB. Fabricated sensor module produced helmholtz coil of which the length is 1.2[m] of 3-axis to know the performance. It installed sensor module at the center and measured the detected magnetic field. In result, 3-axis were detected as 0.2~0.3[mG] and the drift of the fluctuation of magnetic field was stabilized at 0.03[mG] unit. For the performance evaluation of the vehicle detection, after the entry and parking of the vehicle, variation of magnetic field was measured as 0.323~0.695[G] which the average 0.5[G] of the earth magnetic field was the center and the range of variation was confirmed as 0.37[G]. Therefore, the designed magnetic sensor can be used as the vehicle detection sensor module.

• Smart Structures and Systems
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• 제30권4호
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• pp.353-369
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• 2022

In this paper, a new sensor chip with frequency reconstruction range of 2.252 GHz ~ 2.450 GHz is designed and fabricated. On this basis, a self-designed "T-shaped" shell is added to overcome the disadvantage of uneven deformation of the traditional steel shell, and the range of the sensor chip is expanded to 0 kN ~ 96 kN. The liquid metal antenna is used to carry out a step-by-step loading test, and the relationship between the antenna resonance frequency and the pressure load is analyzed. The results show that there is a good linear relationship between the pressure load and the resonant frequency. Therefore, the liquid metal antenna can be regarded as a pressure sensor. The cyclic loading and unloading experiments of the sensor are carried out, and different loading rates are used to explore the influence on the performance of the sensor. The loading and unloading characteristic curves and the influence characteristic curves of loading rate are plotted. The experimental results show that the sensor has no residual deformation during the cycle of loading and unloading. Moreover, the influence of temperature on the performance of the sensor is studied, and the temperature correction formula is derived.

• 로봇학회논문지
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• 제11권3호
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• pp.140-145
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• 2016

In this paper, we fabricate arrayed-type flexible capacitive touch sensor using liquid metal (LM) droplets (4 mm spatial resolution). Poly-4-vinylphenol (PVP) layer is used as a dielectric layer on the electrode patterned Polyethylene naphthalate (PEN) film. Bonding tests between hydroxyl group (-OH) on the PVP film and polydimethylsiloxane (PDMS) are conducted in a various $O_2$ plasma treatment conditions. Through the tests, we can confirm that non-$O_2$ plasma treated PVP layer and $O_2$ plasma treated PDMS can make a chemical bond. To measure dynamic range of the device, one-cell experiments are conducted and we confirmed that the fabricated device has a large dynamic range (~60 pF).

• Journal of Communications and Networks
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• 제14권2호
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• pp.169-178
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• 2012

In this paper, we study the advantages of using range extension cooperative transmission (CT) in multi-hop energy harvesting wireless sensor networks (EH-WSNs) from the network layer perspective. EH-WSNs rely on harvested energy, and therefore, if a required service is energy-intensive, the network may not be able to support the service successfully. We show that CT networks that utilize both range extension CT and non-CT routing can successfully support services that cannot be supported by non-CT networks. For a two-hop toy network, we show that range extension CT can provide better services than non-CT. Then, we provide a method of determining the supportable services that can be achieved by using optimal non-CT and CT routing protocols for EH-WSNs. Using our method and network simulations, we justify our claim that CT networks can provide better services than nonCT networks in EH-WSNs.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1006-1011
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• 1991

In this paper, a neural network estimator which estimates the output of the wide range oxygen sensor is proposed, The neural network estimator is constructed to give the output of the wide range oxygen sensor from rpm, fuel injection time, throttle position, and output voltage of the exhaust gas oxygen sensor. And, using this estimator, PI controller for air-fuel ratio control is designed. Experiment results show that the proposed method gives good results for SONATA engine under light load and constant rpms.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.528-530
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• 2005

In this paper, we present a new and practical method for achieving real-time wavefront measurement, dramatically increasing the resolution, dynamic range of Shack-Hartmann wavefront sensor and improving the wavefront reconstruction quality. In proposal method, a liquid crystal display panel (LCD) for the generation of an array of Fresnel microlenses is use instead of the static microlens array of the conventional Shack-Hartmann type sensor. An off-axis holographic microlens array is designed instead of the normal microlens array to increase the effective array and then the dynamic range. The focus properties of the off-axis lens are studied.

• 한국자기학회지
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• 제23권2호
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• pp.49-53
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• 2013

전류센서는 하이브리드 및 전기자동차의 배터리 충 방전과 모터컨트롤러의 모니터링 시스템에 적용되는 중요한 부품이다. 본 연구에서는 자기코어의 공극에 홀센서를 위치시켜 측정전류에 의해 생성된 자기장을 감지하는 구조를 가진 open loop type의 전류센서를 개발하였다. 코어는 방향성규소강판을 사용하여 제작한 후 공극이 3 mm되게 절단하였다. 공극에서의 자기장 측정을 위하여 GaAs 홀센서를 적용하였다. 개발한 전류센서는 측정범위가 -400~+400 A에서 선형도 0.03 %를 확보하였으며, 온도보상회로를 적용하여 동작온도영역인 $-40{\sim}+105^{\circ}C$에서 전류센서의 온도특성을 향상시켰다. 전류센서의 동특성 향상을 위하여 공기자속를 제어하였다. 주파수대역폭 측정은 $40A{\cdot}turn$, 100 Hz~100 kHz의 사인파형으로 측정하여 100 kHz의 대역폭을 갖는 것으로 평가되었으며, 반응속도는 $40A{\cdot}turn$의 5 kHz 구형파로 측정하여 $2{\mu}s$ 이하의 성능을 갖는 것으로 측정되었다.