• 한국공작기계학회논문집
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• 제13권5호
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• pp.55-61
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• 2004

Chatter monitoring is also important for realizing an unmanned machining system. while many researches were done on this area, it is still a difficult job to detect very small amplitude amount of chattering. A monitoring system using a capacitive spindle displacement sensor was developed to monitor cutting vibration in turning in this research. The variance of the measured spindle displacement signals using the developed sensor was calculated and utilized to quantify the small vibration in machining. The results were compared with variance obtained using a tool dynamometer. The result showed that the developed system could be utilized in monitoring the subtle changes of cutting vibrations with high sensitivity confidence.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.516-522
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• 2003

Monitoring chattering is also important for realizing an unmanned machining system While many researches were done on this area, it is still a difficult job to detect very small amplitude amount of chattering. A monitoring system using a capacitive spindle displacement sensor was developed to monitor cutting vibration in turning in this research. The variance of the measured spindle displacement signals using the developed sensor was calculated and utilized to quantity the small vibration in machining. The results were compared with variance obtained using a tool dynamometer. The result showed that the developed system could be utilized in monitoring the subtle changes of cutting vibrations with high sensitivity confidence.

• 한국정밀공학회지
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• 제19권12호
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• pp.27-32
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• 2002

The intensity modulated type (reflective method) optical fiber sensor is a well -known method and widely applied to the displacement measurements and other industrial purposes. This type sensor has the advantages of relatively cheap cost, small sensor size and easiness of operation. The sensitivity of the sensor is very dependent of several error terms; the variation in the intensity of the light source and the changes in the surface reflectivity of the object. An optical fiber coupled displacement probe with a new compensation method is presented in this paper. The proposed displacement sensor can measure the displacements of the target surface independent of surface reflectivity error that is caused by the materials and surface processing grade.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1250-1251
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• 2022

Measuring management is an important part of preventing the collapse of retaining walls in advance by evaluating their stability with a variety of measuring instruments. The current work of measuring management requires considerable human and material resources since measurement companies need to install measuring instruments at various places on the retaining wall and visit the construction site to collect measurement data and evaluate the stability of the retaining wall. It was investigated that the applicability of the current work of measuring management is poor at small and medium-sized urban construction sites(excavation depth<10m) where measuring management is not essential. Therefore, the purpose of this study is to develop a laser sensor-based hardware to support the wall displacement measurements and their control software applicable to small and medium-sized urban construction sites. The 2D lidar sensor, which is more economical than a 3D laser scanner, is applied as element technology. Additionally, the hardware is mounted on the corner strut of the retaining wall, and it collects point cloud data of the retaining wall by rotating the 2D lidar sensor 360° through a servo motor. Point cloud data collected from the hardware can be transmitted through Wi-Fi to a displacement analysis device (notebook). The hardware control software is designed to control the 2D lidar sensor and servo motor in the displacement analysis device by remote access. The process of analyzing the displacement of a retaining wall using the developed hardware and software is as follows: the construction site manager uses the displacement analysis device to 1)collect the initial point cloud data, and after a certain period 2)comparative point cloud data is collected, and 3)the distance between the initial point and comparison point cloud data is calculated in order. As a result of performing an indoor experiment, the analyses show that a displacement of approximately 15 mm can be identified. In the future, the integrated system of the hardware designed here, and the displacement analysis software to be developed can be applied to small and medium-sized urban construction sites through several field experiments. Therefore, effective management of the displacement of the retaining wall is possible in comparison with the current measuring management work in terms of ease of installation, dismantlement, displacement measurement, and economic feasibility.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.257-258
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• 2006

This paper presents the displacement sensor based on astigmatic method that has a small measurement range. The sensor has the characteristic that the measuring range is changed easily by exchanging a objective lens or distance between a objective lens and a collimator lens. The measuring range and resolution is evaluated by a laser interferometer.

• 제어로봇시스템학회논문지
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• 제20권12호
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• pp.1267-1271
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• 2014

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.

• 전기학회논문지
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• 제60권10호
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• pp.1959-1965
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• 2011

Measuring the movement of joint angle of human body is very important clinically. Human joint angle displacement can be used to evaluate the degree of disease and disability. Also, we can determine the rehabilitation process with angular information. Conventional methods for measuring angular displacement are many weakness. The purpose of this study is to overcome the limitations of existing equipments by using optical method. For this reason, optical sensor system was used to correlate detected light signal with joint angle. Experimental results of the applied joint model in this study showed that joint angular displacement can be measured by optical signals. The suggested method is simple, durable, small, lightweight, convenient, and cost effective.

• 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.

• 한국건설관리학회논문집
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• 제23권1호
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• pp.64-72
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• 2022

흙막이 공사는 지하굴착을 수행하는 건설공사에서 필수적으로 적용되는 공사 기법으로, 공사 규모와 관계없이 흙막이의 계측관리는 필수적이다. 그러나 굴착깊이 10m 미만에 해당되는 소규모 건축현장(총 공사비 20억 내외)의 경우에는 1) 시공업체의 영세성, 2) 현장관리자의 역량 부족, 3) 계측기기 설치·해체 및 변위분석의 복잡성 등의 문제점으로 인해 흙막이의 계측 관리가 제대로 수행되고 있지 않는 실정이다. 상기 문제점을 해결하는 선행연구 분석 결과, 대부분의 선행연구에서는 값비싼 3D 스캐너를 활용하거나 다수의 계측기기를 설치해야 되는 문제점이 있어 소규모 건설현장에 이를 적용하는 것은 어려운 것으로 분석되었다. 따라서 본 연구의 목적은 하나의 계측기기를 활용하여 흙막이 구조체의 변위를 파악할 수 있는 레이저 센서 기반 흙막이 구조체 변위 계측 시스템의 개념 디자인을 제안하고 개념 디자인에 적용된 요소기술의 변위 인식 성능을 검증하는 것이다. 요소기술은 2D 레이저 스캐너가 선정되었으며, 선정된 2D 레이저 스캐너를 활용하여 개념디자인이 제안되었다. 2D 레이저 스캐너의 변위 인식 검증 결과, 15mm의 변위는 충분히 파악 가능한 것으로 분석되었다. 추후, 제안된 개념디자인이 개발되고 현장에 적용될 경우 소규모 건설현장의 안전사고 저감에 기여할 것으로 분석된다.

• 한국정밀공학회지
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• 제20권12호
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• pp.64-72
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• 2003

This paper presents a small loading and positioning device using VCM (voice coil motor). The developed device consists of a VCM-based linear actuating system, a capacitance displacement sensor and a cantilever deflection sensing system. The trust force of the VCM proportional to applied current moves the column supported on two pairs of parallel leaf springs. The infinitesimal displacement of moved column is detected by capacitance displacement sensor with a resolution of 0.1nm and a repeatability of 1nm. Also, a micro cantilever with known stiffness (200N/m), which is mounted on the end of the column, is used as a force sensor to detect the load applied to a specimen. After the cantilever contacts with the specimen, the deflection of cantilever and the load applied to the specimen are measured by using an optical lever system which consists of a diode laser, a mirror and a PSD (position sensitive detector). In this paper, an experimental system was constructed and its actuator and sensing parts were tested and calibrated. Also, the constructed system was applied to the indentation experiment and the load-displacement curve of aluminum was obtained. Experimental results showed that the developed device can be applied for performing nano indentation.