• 센서학회지
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• 제19권3호
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• pp.230-237
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• 2010

In sensor signal conditioning and processing, offset and drift characteristics of an operational amplifier are an important factor when the amplifier is used for a precise sensor signal amplifier. In order to use it in high accuracy, an expensive trimming or a complex compensation circuit is required. This paper presents the improved sensor signal conditioning and processing device for ubiquitous sensor network(USN) application or general purpose by developing a hardware of the circuit for reducing the offset voltage and drift characteristics, and a software for its control and sensor signal processing. We realize better offset voltage and drift characteristics of the signal conditioning circuit using low cost operational amplifiers. The experimental results show that this technique is effective in improving the performance of the sensor signal processing device.

• 센서학회지
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• 제26권2호
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• pp.141-147
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• 2017

A pressure sensor in pulse measurement system is a core component for precisely measuring the pulse waveform of radial artery. A pulse sensor signal that measures the pulse wave in contact with the skin is affected by the temperature difference between the ambient temperature and skin surface. In this study, we found experimentally that the signal changes of the pressure sensors and a temperature sensor were caused by the temperature of the wrist surface while the pressure sensor was contacted on the skin surface for measuring pulse wave. To observe the signal change of the pulse sensor caused by temperature increase on sensor surface, Peltier device that can be kept at a set temperature was used. As the temperature of Peltier device was kept at $35^{\circ}C$ (the maximum wrist temperature), the device was put on the pulse sensor surface. The temperature and pressure signals were obtained simultaneously from a temperature sensor and six pressure sensors embedded in the pulse sensor. As a result of signal analysis, the sensor pressure was decreased during temperature increase of pulse sensor surface. In addition, the signal difference ratio of pressure and temperature sensors with respect to thickness of cover layer in pulse sensor was increased exponentially. Therefore, the signal of pressure sensor was modified by the compensation equation derived by the temperature sensor signal. We suggested that the thickness of cover layer in pulse sensor should be designed considering the skin surface temperature.

• 센서학회지
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• 제32권2호
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• pp.105-109
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• 2023

In this study, we present a power-efficient driving method for gas sensor systems based on the analysis of input signal characteristics. The analysis of the gas sensor output signal characteristics in the frequency domain shows that most of the signal portions are distributed in a relatively low frequency region when extracting the gas sensor signal, which can lead to further performance improvement of the gas sensor system. Therefore, the proposed gas signal extracting technique changes the operating frequency of the read-out circuit based on the frequency characteristics of the output signal of the gas sensor, resulting in a reduction of power consumption at the whole system level. The proposed sensing technique, which can be applied to a general-purpose commercial gas sensor system, was implemented in a printed circuit board (PCB) to verify its effectiveness at the commercial level.

• 로봇학회논문지
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• 제2권3호
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• pp.205-211
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• 2007

In this paper, the prototype of surface EMG (ElectroMyoGram) sensor is developed for the robotic rehabilitation applications, and the developed sensor is composed of the electrodes, analog signal amplifiers, analog filters, ADC (analog to digital converter), and DSP (digital signal processor) for coding the application example. Since the raw EMG signal is very low voltage, it is amplified by about one thousand times. The artifacts of amplified EMG signal are removed by using the band-pass filter. Also, the processed analog EMG signal is converted into the digital form by using ADC embedded in DSP. The developed sensor shows approximately the linear characteristics between the amplitude values of the sensor signals measured from the biceps brachii of human upper arm and the joint angles of human elbow. Finally, to show the performance of the developed EMG sensor, we suggest the application example about the real-time human elbow motion acquisition by using the developed sensor.

• 센서학회지
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• 제23권6호
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• pp.402-408
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• 2014

Heart rate is one of the most important signal to monitor the health condition of the patient or exerciser. Various wearable devices have been developed for the continuous monitoring of ECG signal from human body during exercise. Among these, ECG chest belt has been widely used. However wearing chest belt with ECG sensor is uncomfortable in normal life due to the electrode contact between metal electrodes of ECG sensor and skin of the human body. So we develop the royal healthcare backpack that can measure ECG signal without skin contact by using capacitor-type ECG sensor. The position of the measurement point is critical to collect a clear ECG signal in the capacitive ECG measurement from backpack. Various tests were conducted to find the optimal ECG measurement position which has less noise and could get strong and clear ECG signal during exercise, walking, hiking, mountain climbing and cycling.

• 비파괴검사학회지
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• 제36권6호
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• pp.490-495
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• 2016

펄스와전류탐상에서 탐상 신호는 주로 센서코일에 유도되는 기전력의 시간에 따른 변화를 측정하여 사용되었는데, 최근에는 홀센서(Hall sensor)로 측정한 신호를 사용하는 경우도 많아지고 있다. 본 논문에서는 펄스와전류탐상에서 나타나는 홀센서 신호를 수치적으로 모델링하여 예측하였다. 이를 위해 두께 측정을 위한 탐촉자를 설계하고 먼저 계단입력전류를 사용한 수치해석을 수행하여 홀센서를 사용하였을 경우의 신호를 예측하였다. 또한, 코일을 센서로 사용하였을 경우의 신호도 동시에 계산하였다. 수치모델링 결과로 예측된 홀센서 신호들은 실험 연구를 통해 보고된 신호들과 유사한 형태를 가지고 있음을 확인할 수 있었다. 그리고 피검사체의 두께 변화에 따른 두 신호들의 특성을 분석하고 비교해 본 결과, 홀센서 신호에서는 코일센서 신호에 비해 두께 변화를 판별하기 위한 정보가 더 적게 제공된다는 것을 알 수 있었다. 펄스입력전류를 사용한 경우의 탐상 신호들도 계산해 본 결과, 두 신호 모두 사용된 펄스의 폭이 지난 시간에는 계단입력전류를 사용한 경우의 응답이 반대가 되어 감소하는 형태로 나타난다는 것을 확인할 수 있었다.

• 전기학회논문지
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• 제63권3호
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• pp.409-413
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• 2014

GIS partial discharge that occurred in the UHF band signal is effectively detected by the method to IEC60270 5pc the apparent minimum discharge can be detected over the GIS arrangement of the sensor interior and exterior of the UHF in accordance with the optimized position signal by considering the damping ratio is selected so that the signals can be obtained to be mounted. 362kV, 800kV GIS is installed on the internal and external sensors are UHF band signal attenuation is set by measuring the reference value, but the operation, 170kV case 362kV, 800kV on the basis of the measurement data and to be installed and operated. When 170kV per 1Bay by installing the built-in sensor 1 for detecting a partial discharge signal, But, GIS signal attenuation is large in the case of an internal partial discharge signal is not detected in some cases. Where the attenuation is great UHF signal of the sensor by increasing the quantity of partial discharge signals were acquired to allow relocation. The greater the spacing between the sensor and the sensor is applied simplifies the installation and reduces the cost in terms of maintenance of appropriate optimal position is calculated to detect the partial discharge signal is needed. Thus 170kV GIS signal power attenuation of a partial discharge by measuring the UHF sensor, and by relocating the proper position is calculated in accordance with the sensor signal decay rate and minimize the error of omission in detecting a partial discharge signal was optimized.

• International Journal of Control, Automation, and Systems
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• 제3권3호
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• pp.469-476
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• 2005

Performance of a force-torque sensor is affected significantly by an error signal that is included in the sensor signal. The error sources may be classified mainly into two categories: one is a structural error due to inaccuracy of sensor body, and the other is a noise signal existing in sensed information. This paper presents a principle of 6-axis force-torque sensor briefly, a double-hole structure to be able to improve a structural error, and then a signal conditioning to reduce the effect of a noise signal. The validity of the proposed method is investigated through experimental study, which shows that SIN ratio is improved significantly in our experimental setup, and the sensor can be implemented cheaply with reasonable performance.

• 전기학회논문지P
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• 제66권2호
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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..

• 한국기계가공학회지
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• 제14권5호
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• pp.28-35
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• 2015

This paper introduces a resistance scanning-type flexible tactile sensor for intelligent robots and presents the output characteristics of the sensor via signal processing. The sensor was produced via the lamination method using multi-walled carbon nanotubes (a conductive material), an insulator, and Tango-plus (an elastic material). Analog and digital signal processing boards were produced to analyze the output signal of the sensor. The analog signal processing board was made up of an integrator and an amplifier for signal stability, and the digital signal processing board was made up of an IIR filter for noise removal. Finally, the sensor output for the contact force was confirmed through experiments.