• Journal of Sensor Science and Technology
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• v.22 no.3
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• pp.191-196
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• 2013

A particulate matter sensor fabricated by MEMS process is proposed. It is developed to accommodate Euro6 on-board diagnostics regulation for diesel automobile. In the regulation, emission of diesel particulate matter is restricted to 9 mg/km. Particulate matter sensor is designed to use induced charges by charged particulate matter. To increase sensitivity of the sensor, groove is formed on sensor surface because wider surface area generates more induced charges. Sensitivity of the sensor is measured 10.6 mV/(mg/km) and the sensor shows good linearity up to 15.7 mg/km. Also its minimum detectable range is about 0.25 mg/km. It is suitable to detect failure of a diesel particulate filter which should filter particulate matter more than 9 mg/km. For removing accumulated particulate matter on the sensor which can disturb normal operation, platinum heater is designed on the backside of the sensor. The developed sensor can sense very low amount of particulate matter from exhaust gas in real-time with good linearity.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.114-121
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• 2017

This paper describes the design and fabrication of a three-axis force sensor with parallel plate beams (PPSs) for measuring the calf force while a patient with a walking assist robot is walking. Current walking assist robots can't measure the weight of the patient's leg and the robot's leg which required for robot control. So, the three-axis force sensor in the calf link is designed and manufactured, it is composed of a Fx force sensor, a Fy force sensor and a Fz force sensor. The three-axis force sensor was designed using by FEM(Finite Element Method), and fabricated using strain-gages. The characteristics experiment of the three-axis force sensor was carried out respectively. The test results indicated that the repeatability error and the non-linearity error of three-axis force sensor was less than 0.04% respectively. Therefore, the fabricated three-axis force sensor in the calf link can be used to measure the patient's calf force in the walking assist robot.

• Progress in Medical Physics
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• v.13 no.1
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• pp.44-50
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• 2002

CsI(T1) single crystal was grown in a Bridgman growing apparatus, which has the diameter of 11 mm and the mole ratio of 0.001 mol%. Radiation sensors were made with CsITl)crystal and two photodiodes, and measured spectroscopic characteristics and linearity for gamma-ray and X-ray. The energy resolution of CsI(T1) radiation sensor has been measured with $^{22}$ Na, $^{137}$ Cs and $^{60}$ Co gamma standard sources. Also output linearity of CsITl) sensor was measured for diagnostic radiation region. The energy resolutions of CsI(T1) radiation sensor for 0.511MeV gamma-ray from Na-22 source, 0.662MeV from Cs-137 source, and 1.17MeV and 1.332MeV from Co-60 source were 13.2%, 8.3%, 6.7%, and 5.1% respectively. Also the output linearity up to 80mAs current for 60kVp, 80kvp, 100kVp, 120kVp tube voltages has been studied.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.3
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• pp.226-232
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• 2016

This paper describes the design of a smart three-axis force sensor for measuring forces Fx, Fy and Fz. The smart three-axis force sensor is composed of a three-axis force sensor, a force-measuring device, housing and a cover, where the three-axis force sensor and the force-measuring device are inside the housing and the cover. The measuring device measures forces Fx, Fy and Fz from the three-axis force sensor, and calculates the resultant force using the measured forces, and then sends the resultant force and forces to a PC or other controller using RS-485 communication. The repeatability error and the non-linearity error of the smart three-axis force sensor are less than 0.03%, and the interference error of the sensor is less than 0.87%. It is thought that the sensor can be used for measuring forces in a robot, automatic systems and so on.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.524-529
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• 2016

We describe the design and fabrication of a two-axis force/torque sensor with parallel-plate beams (PPBs) and single beams for measuring force and torque in hip-joint rehabilitation exercise using a lower rehabilitation robot. The two-axis force/torque sensor is composed of an Fz force sensor and a Tz torque sensor, which detect z direction force and z direction torque, respectively. The two-axis force/torque sensor was designed using the FEM (Finite Element Method) and manufactured using strain gages. The characteristics experiment of the two-axis force/torque sensor was carried out. The test results show that the interference error of the two-axis force/torque sensor was less than 0.64% and the repeatability error and the non-linearity of the two-axis force/torque sensor were less than 0.03%. It is thought that the developed two-axis force/torque sensor could be used for a lower rehabilitation robot.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.154-157
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• 2003

Precision displacement of less than a few nm resolution was measured in real-time using fiber optic EFPI sensor. The novel method for real-time processing of analyzing EFPI output signal was developed and verified. Linearity in the mean values of interferometric light intensity among adjacent fringes was shown, and the sinusoidal approximation algorithm that estimates past and coming fringe values was verified through the linearity. Real-time signal processing program was developed, and the intensity signal of the EFPI sensor was transformed to the phase shift with this program. The resolution below 0.4 ~ 10 nm in the displacement range of $0 ~ 300\mu\textrm{m}$ was obtained by reducing the photodetector noise using low-pass filter and signal averaging. The nano-translation stage with a Piezo-electric actuator and the EFPI sensor system was designed and tested. This stage successfully reached to the desired destination in $15\mu\textrm{m}$ range within 1 nm accuracy.

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.194-201
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• 2015

The current sensor is used in industrial devices and power utilities. Core materials of these current sensors are divided into mainly two groups as silicon steel and fermalloy. Silicon steel has a wide saturation bandwidth but low sensitivity during low-current, whereas permalloy has a short saturation bandwidth but high sensitivity during low-current. In this paper, laminated silicon steel and permalloy by equal ratio is proposed to improve the linearity and saturation of current sensor. It is proved that the proposed core material has larger bandwidth than fermalloy as well as higher sensitivity than silicon steel. When comparing simulation results by FLUX 3D, the proposed method has also better performance than the previous core materials.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.2
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• pp.82-87
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• 2017

This paper presents performance improvement of CO gas sensor signal conditioner for early fire warning system. The warning system is based on the CO sensor and its advanced signal conditioning modules network that employ electochemical gas sensor. The electochemical has advantage of having a linear output and operating with a low consumption and fast response. This electrochemical gas sensor contains a gas membrane and three electrodes(working, counter, reference electrode) in contact with an electrolyte. To use a three-electrode sensor, a voltage has to be applied between the working and the reference electrode according to the specification of the sensor. In this paper, we designed these requirements that should be considered in temperature compensation algorithm and electrode measurement of CO sensor modules by using advanced signal conditioning method included 3-electrode. Simulation and experimental results show that signal conditioner of CO sensor module using 3-electrode have a advantage linearity, sensitivity and stability, fast response etc..

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.1
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• pp.89-98
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• 2002

Optical current sensor and optical voltage sensor modules were designed and fabricated to improve measurement error and insulation in automatic power distributor By using Faraday effect, optical current sensor with an $\alpha$-iron core was designed and fabricated to minimize current induction of the other phase and was optimized to maintain linearity. Optical voltage sensor was fabricated owing to the pockets effect and adopted spatial electric field type because of small room in an automatic power distributor. To connect a distributor with an external terminal for signal processing, optical multi connector was designed, fabricated and tested for coupling loss and gas leakage. The linearity of optical current sensor for applied current maintains variation of smaller than 2.5% for applied current range from 20A to 700A. The linearity of optical voltage sensor was smaller than 1% for appling voltage from 6.6kV to 19.8kV. Since the measured characteristics are good, these devices can be considered as being applicable in practice.

• Journal of Power System Engineering
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• v.21 no.5
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• pp.71-78
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• 2017

The purpose of this study is to propose the basic data for the development of a sensor capable of simultaneously measuring the liquid-level, concentration and temperature of a urea tank using ultrasonic and electrical conductivity sensors for diesel vehicles with a urea-SCR system. It was found that the liquid-level of the urea tank using the ultrasonic sensor showed a good linearity with the actual liquid-level, and the urea concentration maintained good linearity in the range of 32.5 wt% to 10 wt%. It was an effective measurement of urea concentration to use the electrical conductivity sensor in the temperature range of $-10{\sim}22^{\circ}C$ and to use the ultrasonic sensor at $22^{\circ}C$ or more. Simultaneous measurement of concentration, liquid-level and temperature of the urea tank will be possible by attaching the electrical conductivity sensor and the ultrasonic sensor (split-type) to one sensor together.