가스 센서모듈 및 센서보정시스템 개발

박철영(Cheol-Young Park),임병훈(Byung-Hun Lim),류정탁(Jeong-Tak Ryu) 한국산업정보학회 2010 한국산업정보학회논문지 Vol.15 No.2

센서는 센서네트워크와 같은 다양한 센서시스템에 응용되고 있는 핵심부품이다. 그러나 센서는 온도에 따른 출력특성과 비선형성을 가지기 때문에 개발이 쉽지 않다. 이러한 문제점을 해결하기 위해서는 센서의 보정과정이 필요 하지만 현재의 센서보정과정에서는 많은 보정시간과 비용을 요구하고 있다. 그러므로 보정시간과 비용을 최소화할 수 있는 보정시스템 개발이 필요하다. 본 논문에서 CO 및 CO₂ 센서모듈 개발과 현재의 보정방법에서의 문제점들을 해결할 수 있는 다수센서보정시스템을 제안한다. 제안하는 시스템은 센서모듈, 시스템보드 및 모니터링프로그램 등으로 구성되며 보정은 최소자승법을 기반 한 회귀분석 방법을 사용한다. 제안한 보정시스템의 구성 및 실험결과에 대해 소개하고 결과를 바탕으로 시스템의 유효성을 검증한다. Sensor is a key element in various fields of applications such as sensor networks. However, they could not be easily developed because of several factors such as temperature dependence of output characteristics and/or nonlinearity. Calibration of sensor is also needed to solve these problems. Conventional calibration process required a lot of time and expenses. Therefore, it is important to develop sensor systems which can shorten development time and minimize expense. In this paper, we develop CO and CO₂ Sensor modules and propose a multiple sensor calibration system to resolve problems of conventional calibration process. A proposed system is composed of sensor module, system board and monitor program. Regression analysis method based on the least mean squares is used for calibration. We introduced the structure of calibration systems and experimental results. Calibration results can be used to confirm the effectiveness of the proposed system.

멀티모달 센서 시스템용 유전자 알고리즘 보정기 및 PnP 플랫폼

이재학(Jea Hack Lee),김병수(Byung-Soo Kim),박현문(Hyun-Moon Park),김동순(Dong-Sun Kim),권진산(Jin-San Kwon) 한국전자통신학회 2019 한국전자통신학회 논문지 Vol.14 No.1

본 논문은 PnP(plug and play) 기술을 지원하는 멀티모달 센서 플랫폼을 제안하였다. PnP 기술은 센서 모듈이 연결이 되면 자동으로 인식하여 응용프로그램을 사용하여 손쉬운 센서 제어를 제공한다. 멀티모달 플랫폼을 검증하기 위해, 펌웨어 를 사용하여 센서를 실험하였다. 센서 모듈이 연결되면 펌웨어는 센서 모듈을 인지하여 센서 데이터를 읽는다. 따라서, PnP 기술 지원을 통해 소프트웨어 설정 없이 자동으로 센서를 연동할 수 있게 된다. 측정한 센서 데이터는 다양한 왜곡에 의해 오류를 가지고 있다. 따라서, 본 논문은 다항식 계산을 통해 센서의 오류를 보상하고자 한다. 다항식 보상기의 계수를 찾기 위해 유전자 알고리즘 방식을 사용하였다. 실험결과 악조건에서 97%의 오류를 제거하였다. 또한, 제안하는 플랫폼은 다양한 프로토콜의 센서를 지원하기 위해 UART, I2S, I2C, SPI, GPIO를 지원한다. This paper proposes a multimodal sensor platform which supports plug and play (PnP) technology. PnP technology automatically recognizes a connected sensor module and an application program easily controls a sensor. To verify a multimodal platform for PnP technology, we build up a firmware and have the experiment on a sensor system. When a sensor module is connected to the platform, a firmware recognizes the sensor module and reads sensor data. As a result, it provides PnP technology to simply plug sensors without any software configuration. Measured sensor raw data suffer from various distortions such as gain, offset, and non-linearity errors. Therefore, we introduce a polynomial calculation to compensate for sensor distortions. To find the optimal coefficients for sensor calibration, we apply a genetic algorithm which reduces the calibration time. It achieves reasonable performance using only a few data points with reducing 97% error in the worst case. The platform supports various protocols for multimodal sensors, i.e., UART, I2C, I2S, SPI, and GPIO.

드론 탑재 복합센서의 매핑 정확도 분석: 데이터 취득 환경에 따른 사전 캘리브레이션 여부를 중심으로

전일서 ( Ilseo Jeon ),함상우 ( Sangwoo Ham ),이임평 ( Impyeong Lee ) 대한원격탐사학회 2021 大韓遠隔探査學會誌 Vol.37 No.3

드론 매핑 시스템은 재난 피해 조사, 국토 환경 모니터링, 건설 공정 모니터링 등 여러 분야에 응용 가능하다. 드론에 장착된 다양한 개별 센서를 통합하여 활용하려면 시간동기화 등 여러가지 절차가 필요했다. 최근, 영상 센서와 GPS/INS가 함께 내장된 복합센서가 다수 출시되었다. 복합센서는 여러 가지 센서 데이터를 내부적으로 통합하여, 위치/자세를 영상 파일에 바로 태깅하여 제공한다. 이러한 복합센서를 드론 매핑 시스템에 활용하려면 매핑 정확도를 확인해 볼 필요가 있다. 이에 본 연구에서는 다양한 데이터 취득 환경과 사전 캘리브레이션 여부를 중심으로 복합센서의 매핑 정확도를 확인하였다. 첫째, 매핑 정확도가 지상기준점의 개수에 따라 어떻게 변하는지 살펴보았다. 지상기준점 개수가 2개일 때부터 총 RMSE가 1 m 이상에서 약 60 cm로 40 cm가량 줄어드는 것을 확인할 수 있었다. 둘째, 데이터 취득 상황과 사전 캘리브레이션 여부에 따른 매핑정확도를 확인하였다. 지상기준점이 있는 경우에는 개수가 적을지라도 사전 캘리브레이션의 영향이 크지 않은 것을 확인할 수 있었다. 영상의 중복도가 충분하지 않을 때는 사전 캘리브레이션 하는 것이 정확도 개선에 영향을 주는 것을 확인할 수 있었다. 지상기준점이 없는 경우에는 카메라, 탑재체 모두 사전 캘리브레이션 하는 것이 정확도를 개선시키는데 영향이 있음을 확인하였다. 본 연구를 기반으로, 향후 복합센서를 이용한 드론 매핑 수행 시 데이터 취득 조건에 따라 지상기준점 측량과 캘리브레이션 과정을 효율화 하는데 기여할 것으로 기대한다. Drone mapping systems can be applied to many fields such as disaster damage investigation, environmental monitoring, and construction process monitoring. To integrate individual sensors attached to a drone, it was essential to undergo complicated procedures including time synchronization. Recently, a variety of composite sensors are released which consist of visual sensors and GPS/INS. Composite sensors integrate multi-sensory data internally, and they provide geotagged image files to users. Therefore, to use composite sensors in drone mapping systems, mapping accuracies from composite sensors should be examined. In this study, we analyzed the mapping accuracies of a composite sensor, focusing on the data acquisition area and pre-calibration effect. In the first experiment, we analyzed how mapping accuracy varies with the number of ground control points. When 2 GCPs were used for mapping, the total RMSE has been reduced by 40 cm from more than 1 m to about 60 cm. In the second experiment, we assessed mapping accuracies based on whether pre-calibration is conducted or not. Using a few ground control points showed the pre-calibration does not affect mapping accuracies. The formation of weak geometry of the image sequences has resulted that pre-calibration can be essential to decrease possible mapping errors. In the absence of ground control points, pre-calibration also can improve mapping errors. Based on this study, we expect future drone mapping systems using composite sensors will contribute to streamlining a survey and calibration process depending on the data acquisition circumstances.

Evaluation of Robot Calibration Performance based on a Three Dimensional Small Displacement Measuring Sensor

Hoai-Nhan Nguyen,Hee-Jun Kang(강희준) 제어로봇시스템학회 2014 제어·로봇·시스템학회 논문지 Vol.20 No.12

There have been many autonomous robot calibration methods which form closed loop structures through the various attached sensors and mechanical fixtures. Single point calibration among them has been used for on-site calibration due to its convenience of implementation. The robot can reach a single point with infinitely many configurations so that single point calibration algorithm can be set up and easily implemented relative to the other methods. However, it is not still easy to drive the robots’ sharp edge to its corresponding edge of the fixture. This is error-prone process. In this paper, we propose a 3 dimensional small displacement measuring sensor and a robot calibration algorithm based on this sensor. This method relieves the difficulty of matching two edges in the single point calibration and improves the resulting robot accuracy. Simulated study is carried out on a Hyundai HA06 robot to show the effectiveness of the proposed method over the single point calibration. And also, the resulting robot accuracy is compared with that from 3D laser tracker based calibration to show the dependency of robot accuracy on range of the workspace where the measurement data are collected.

부양형 탄소나노튜브 나노시트를 이용한 pH센서의 제작과 보정

유효봉 ( Hyo Bong Ryu ),최우석 ( Woo Seok Choi ),안태창 ( Tae Chang An ),허준성 ( Joon Seong Heo ),임근배 ( Geun Bae Lim ) 한국센서학회 2013 센서학회지 Vol.22 No.3

In this research, the pH sensor was developed using CNT nanosheet with Nafion coating for the advanced medical sensor such as a blood gas analyzer. The CNT nanosheet was formed by dielectrophoresis and water-meniscus between cantilever-type electrodes. Then, the process of the heat annealing and the Nafion coating was conducted for reducing contact resistance and giving proton selectivity respectively. We measured the response of the pH sensor as the electrolyte-gated CNT-nanosheet field effect transistor. The sensor showed a linear current ratio in a similar range of the normal blood pH. The calibration method was also introduced for decreasing the response variation of between sensors. Coefficient of variance of the pH sensor was decreased by applying the calibration method. A linear relation between the calibrated response of the sensors and pH variance was also obtained. Finally, the pH sensor with a high resolution was fabricated and we verify the feasibility of the sensor by applying the calibration method.

Hybrid Sensor Calibration Scheme for Mobile Crowdsensing–Based City-Scale Environmental Measurements

손승철,이병탁,고석갑,강경란 한국전자통신연구원 2016 ETRI Journal Vol.38 No.3

In this paper, we propose a hybrid sensor calibration scheme for mobile crowdsensing applications. As the number of newly produced mobile devices containing embedded sensors continues to rise, the potential to use mobile devices as a sensor data source increases. However, because mobile device sensors are generally of a lower performance and cost than dedicated sensors, sensor calibration is crucial. To enable more accurate measurements of natural phenomena through the use of mobile device sensors, we propose a hybrid sensor calibration scheme for such sensors; the scheme makes use of mobile device sensors and existing sensing infrastructure, such as weather stations, to obtain dense data. Simulation results show that the proposed scheme supports low mean square errors. As a practical application of our proposed scheme, we built a temperature map of a city using six mobile phone sensors and six reference sensors. Thanks to the mobility of the sensors and the proposed scheme, our map presents more detailed information than infrastructure-based measurements.

저궤도 영상촬영위성 자세제어 센서의 절대 오정렬 보정

윤형주,박근주,임조령,서두천,김희섭,최홍택 한국항공우주학회 2012 한국항공우주학회 학술발표회 논문집 Vol.2012 No.11

본 연구에서는 지구 저궤도상의 고해상도 지상영상 촬영위성의 자제제어 센서와 영상촬영 탑재체 간의 절대 오정렬을 추정하여 보정하는 기법에 대해 다루고 있다. 원하는 지상 목표의 고해상도 영상을 촬영하고, 촬영한 영상의 정확한 위치정보를 추출하기 위해서는 별추적기 센서나 자이로 센서 등의 자세제어 센서의 정확한 정렬정보가 필요하다. 이때 영상을 촬영하는 영상 탑재체의 좌표축에 대한 자세제어 센서의 오정렬을 절대 오정렬이라고 한다. 본 논문에서는 별추적기 센서에서 사용되는 2 차원 평면 영상센서의 자세결정 기법을 응용하여, 1 차원 선형 배열 영상센서를 이용한 영상 탑재체와 자세제어 센서간의 절대 오정렬 정보를 추정하는 기법을 제시하였다. The present study proposes a new method for absolute misalignment calibration of attitude sensors of low-Earth-orbit imaging satellites. In order to accurately point the satellite imaging payload camera to a ground target and to acquire accurate location data from the images, it is indispensable to have accurate absolute alignment data of the attitude sensors, such as star tracker sensors, gyro sensors, etc., with respect to the payload. Applying the conventional attitude determination methods for star tracker sensor with 2-dimensional planar image sensors, the present paper provides a new technique which identifies the absolute misalignment of the attitude sensors relative to the imaging payload which uses a 1-dimensional linear array imaging sensor.

A GPS-IMU-Camera Modelization and Calibration for 3D Localization dedicated to Outdoor Mobile Applications

I.M. Zendjebil,F. Ababsa,J-Y. Didier,M. Mallem 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

3D localization is an important process for many types of applications such as augmented reality or mobile robotics. To achieve this, outdoor applications converge towards using hybrid sensor systems. The combination of different types of sensors tends to overcome the drawbacks of using a single type of sensor and thus increases the robustness and the accuracy. However, the combination of several types of sensors must deal with various problems. Among them, the calibration represents an important step. Indeed, each sensor provides measurements in its own coordinate system. So, we need to convert the measurements provided by each sensor in its own coordinate systems into a reference coordinate system. This process consists in estimating transformations that maps one coordinate system to another. The accuracy of the hybrid sensor depends on the accuracy of this procedure. In our work, we are interested in using three types of sensors: a camera, an inertial sensor (IMU) and a GPS receiver. This hybrid sensor must provide at any time the position and the orientation of the camera point of views w.r.t. the world coordinate system (camera pose). Thus, orientations provided by the IMU and GPS positions must be re-expressed in the camera coordinate system. In this paper, we propose two calibration approaches based on models associated to each pair of sensors. Some results of experiments conducted under real conditions will also be presented.

유닛형 공기조화기 센서의 가상보정 방법 및 적용 특성 분석

윤성민(Sungmin Yoon),김용식(Yong-Shik Kim) 한국태양에너지학회 2018 한국태양에너지학회 논문집 Vol.38 No.6

Since data-driven building technologies have been widely applied to building energy systems, the accuracy of building sensors has more impacts on the building performance and system performance analysis. Various building sensors, however, can have typical errors including a random error (noise) and a systematic error (bias). The systematic error is indicated by the difference between the mean of measurements and their true value. It may occur due to the sensor’s physical condition, measured phenomena, working environments inside the systems. Unfortunately, a conventional calibration method has limitations in calibrating the systematic errors because of the difference between working environments and calibration conditions. In such situations, a novel sensor calibration method is needed to handle various sensor errors, especially for systematic errors, in building energy systems having various thermodynamic environments. This study proposes a building sensor calibration method named Virtual In-situ Calibration (VIC) and shows how it is applied into a real building system and how it solves the sensor errors.

Uncertainty Evaluation of a multi-axis Force/Moment Sensor

Kim, Gab-Soon Korean Society for Precision Engineering 2002 International Journal of the Korean Society of Pre Vol.3 No.3

This paper describes the methods for calibration and evaluation of the relative expanded uncertainty of a multi-axis force/moment sensor. In order to use the sensor in the industry, it should be calibrated and its relative expanded uncertainty should be also evaluated. At present, the confidence of the sensor is shown with only interference error. However, it is not accurate, because the calibrated multi-axis force/moment sensor has an interference error as well as a reproducibility error of the sensor, etc. In this paper, the methods fur calibration and for evaluation of the relative expanded uncertainty of a multi-axis force/moment sensor are newly proposed. Also, a six-axis force/moment sensor is calibrated with the proposed calibration method and the relative expanded uncertainty is evaluated using the proposed uncertainty evaluation method and the calibration results. It is thought that the methods fur calibration and evaluation of the uncertainty can be usually used for calibration and evaluation of the uncertainty of the multi-axis force/moment sensor.