• 로봇학회논문지
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• 제6권1호
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• pp.42-48
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• 2011

It is very important for a mobile robot to recognize and model its environments for navigation. However, the grid map constructed by sonar sensors cannot accurately represent the environment, especially the narrow environment, due to the angular uncertainty of sonar data. Therefore, we propose a map building scheme which combines sonar sensors and IR sensors. The maps built by sonar sensors and IR sensors are combined with different weights which are determined by the degree of translational and rotational motion of a robot. To increase the effectiveness of sensor fusion, we also propose optimal sensor arrangement through various experiments. The experimental results show that the proposed method can represent the environment such as narrow corridor and open door more accurately than conventional sonar sensor-based map building methods.

• 로봇학회논문지
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• 제2권1호
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• pp.71-79
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• 2007

We propose and develop Home Security robot system based on Sensor Network (HSSN) configured by sensor nodes including radio frequency (RF), ultrasonic, temperature, light and sound sensors. Our system can acknowledge security alarm events that are acquired by sensor nodes and relayed in the hop-by-hop transmission way. There are sensor network, Home Security Mobile Robot (HSMR) and Home Server(HS) in this system. In the experimental results of this system, we presented that our system has more enhanced performance of response to emergency context and more speedy and accurate path planning to target position for arriving an alarm zone with obstacle avoidance and acquiring the context-aware information.

• 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.

• International journal of advanced smart convergence
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• 제6권3호
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• pp.59-64
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• 2017

A wireless sensor network is a network in which nodes equipped with sensors capable of collecting data from the real world are configured wirelessly. Because the sensor nodes are configured wirelessly, they have limited power such as batteries. If the battery of the sensor node is exhausted, the node is no longer usable. If more than a certain number of nodes die, the network will not function. There are many wireless sensor network protocols to improve energy efficiency, among which LEACH Protocol is a typical example. The LEACH protocol is a cluster-based protocol that divides sensor space into clusters and transmits and receives data between nodes. Therefore, depending on how the cluster is structured, the shape of the energy cow may decrease or increase. We compare the network lifetimes of the existing LEACH protocols and the three types of protocols that have been improved using fuzzy methods for cluster selection.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권9호
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• pp.443-448
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• 2006

Non-contacting capacitive sensor based on Thompson-Lampard theorem have been fabricated and characterized for measuring of 때 order displacements. To overcome disadvantages of the existed capacitive sensors of parallel plate type with 2-electrodes and 3-electrodes, the developed new sensor was designed to have 4-electrodes with a constant gap of 0.2mm between the electrodes. Two of the electrodes were used as a high potential electrode and a low one, the other two electrodes were used as guard electrodes. These electrodes were made from copper using RF sputtering system on a sapphire plate with diameter 17 mm and thickness 0.7 mm. This sensor can be used for measuring the distance not only between the sensor and metallic target connected to ground potential but also non-metallic target without ground connection.

• 한국정밀공학회지
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• 제22권8호
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• pp.42-49
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• 2005

Our purpose is to develop a precision magnetic displacement sensor that has sub-micron resolution and small size probe. To achieve this, we first have tried to establish mathematical models of a magnetic sensor in this paper. The inductance model that presents basic measuring principle of a magnetic sensor is based on equivalent magnetic circuit method. Especially we have concentrated on modeling of magnetic flux leakage and magnetic flux fringing. The induced model is verified by experimental results. The model, including the magnetic flux leakage and flux fringing effects, is in good agreement with the experimental data. Subsequently, based on the augmented model, we will design magnetic sensor probe in order to obtain high performances and to scale down the probe.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.393-397
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• 1996

A stewart platform-based force/torque sensor with 6 elastic legs was designed and manufactured Kinematic design parameters were determined so that the force/torque sensor might have the isotropic force/torque properities. In a force/torque analysis, it was used the solution of forward kinematics by linearization of the solution of the inverse kinematics. The performance of te force/torque sensor was investigated by measurement experiments. The gravity compensation was conducted to reduce the force and torque effects by the weights of the upper plate, joints and other sensor parts.

• 센서학회지
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• 제25권3호
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• pp.161-172
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• 2016

The use of a chemical sensor array can help discriminate between chemicals when comparing one sample with another. The ability to classify pattern characteristics from relatively small pieces of information has led to growing interest in methods of sensor recognition. A variety of pattern recognition algorithms, including the adaptive radial basis function network (RBFN), may be applicable to gas and/ or odor classification. In this paper, we provide a broad review of approaches for various types of gas and/or odor identification techniques based on RBFN and drift compensation techniques caused by sensor poisoning and aging.

• 분석과학
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• 제28권1호
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• pp.8-16
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• 2015

We prepared a novel electrochemical gas sensor (EG sensor) based on interdigitated electrode (IDE) coated with vinyl ionic liquids (ILs) as electrolyte and Pt-Ru-Mo/MWNT electrocatalysts for occurring redox-active of CNCl gas. The vinyl ILs such as 1-butyl-3-(vinylbenzyl)imidazolium chloride, $[BVBI]^+Cl^-$, and 3-hexyl-1-vinylimidazolium bromide, $[HVI]^+Br^-$, were synthesized by $SN_2$ reaction in order to use electrolyte. The Pt-Ru-Mo/MWNT electrocatalysts were also prepared by one-step radiation-induced reduction of metal ions in the presence of MWNTs as supports. The fabricated EG sensor with vinyl ILs electrolyte was evaluated through optical microscopy (OM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The prepared EG sensor is clearly detected over 2.0 ppm CNCl gas and is exhibited a liner relationship between current and concentration over a region of 10-100 ppm.