• 대한기계학회논문집A
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• 제26권12호
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• pp.2687-2694
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• 2002

A precision displacement measuring system is proposed, which can detect the 3-DOF translational motions of precision positioning devices. The optical system, which is composed of two diode-laser sources and two quadratic PSDs, is adapted to detect the position of the spherical reflector usually mounted on the platform of positioning devices. Each of the laser beams from diode-laser sources is reflected at the highly reflective surface of the sphere; hence, the 3-dimensional position of the sphere causes the directional change of the reflected beams, which is detected by the PSDs. In this paper, we define the relationships between the output values of the two PSDs and the 3-DOF translational motions of the sphere. Based on a deduced measurement model, we perform measurement simulation and evaluate the performance of the proposed measurement system: linearity, sensitivity, measuring range, and measurement error. The results show that the proposed measuring method is very useful for the measurement of the precision displacement of 3-DOF micro motions.

• 동력기계공학회지
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• 제15권1호
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• pp.72-77
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• 2011

The handling ability of containers at the terminal strongly depends on the performance of the cargo handling system such as RTGC(Rubber Tired Gantry Crane). This paper introduces a new guide line position measurement method using a camera for the RTGC which plays a important role in the harbor area. Because the line tracking is the basic technique for control system design of RTGC, it is necessary to develop a useful and reliable measurement system. If the displacement and angle of the RTGC relative to a guide line as trajectory to follow is obtained, the position of RTGC is calculated. Therefore, in this paper, a camera-based measurement system is introduced. The proposed measurement system is robust against light fluctuation and cracks of the guideline. This system consists of a camera and a PC which are installed at the lower side of the RTGC. Two edges of the guide line are detected from an input image taken by the camera, and these positions are determined in a Hough parameter space by using the Hough transformation method. From the experimental results, high accurate standard deviations were found as 0.98 pixel of the displacement and 0.24 degree of the angle, including robustness against lighting fluctuation and cracks of the guide line also.

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.688-693
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• 2007

The INS/GPS integration system is designed by employing an adaptive filter that can estimate the measurement noise variance using the residual of the filter. To verify the efficiency of the proposed loosely-coupled INS/GPS integration system, simulation is performed by assuming that GPS information has large position errors. Simulation results show that the proposed integration system with the adaptive filter is more effective in estimating the position and attitude errors than those with the Extended Kalman Filter.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.63-63
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• 2000

This paper is about the method to improve the IDGPS system using receiver which is not aligned to GPS time. Transmitted data between server and user is constructed in PDDM of IS-801 rule. Pseudorange is overflowed in case of using receiver unaligned GPS time. And satellite position is miscalculated because earth rotating effect is not corrected. To solve this problem, when Pseudorange measurement is over the maximum range, the Pseudorange measurement is reset. And after the rough user position and transmit time is calculated, the precise Pseudorange measurement is calculated.

• 한국전문물리치료학회지
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• 제16권3호
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• pp.1-8
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• 2009

It is important to find the effective position for cough and sputum clearance in respiratory physical therapy. The purpose of this study was to compare the changes in peak expiratory flow (PEF), forced expiratory volume in 1 second ($FEV_1$), and peak cough flow (PCF) related to functional level and measurement position in patients with Duchenne muscular dystrophy. Twenty one subjects were classified into three functional levels, and measurements was undertaken in three different measurement positions (upright sitting, $45^{\circ}$ reclining and supine). Vitalograph PEF/FEV DIARY was used to measure PEF and $FEV_1$, and Ferraris Pocket Peak was used to measure PCF. Mixed two-way analysis of variance and Bonferroni post-hoc test were used for statistical analysis. The results of the study were as follows: 1) Significant main effects for measurement position were found. 2) PEF was the highest in upright sitting, followed by $45^{\circ}$ reclining, and supine in order. 3) $FEV_1$ in upright sitting and $45^{\circ}$ reclining were significantly greater compared with that in supine. 4) PCF in upright sitting and $45^{\circ}$ reclining were significantly greater compared with that in supine. 5) No significant main effects for functional level were found in PEF, $FEV_1$, and PCF. 6) No significant functional level by measurement position interactions were found in PEF, $FEV_1$, and PCF. Therefore, it is concluded that upright sitting and $45^{\circ}$ degree reclining positions are recommended for effective cough and sputum clearance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.964-968
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• 2007

The measurement of floor impact sound have been standardized in KS 2810-1 and 2. The height of receiving microphones position is specified in the standard as 1.2m which is almost half height of apartment rooms as a listening position. In this study, receiving positions are investigated by measuring the distribution of sound pressure levels at 792 receiving microphone positions in the standard testing building. Standard impact sources, tapping machine and impact ball, are driven on the center position in the source room where is located at the above floor. It was found that the distribution of sound pressure levels in the receiving room indicates significant deviation at different frequencies there is more than 5dB drop at 63Hz but 2dB rise at 125Hz at a height of 1.2m when the impact ball is driven, in the other case of a generating tapping machine there is more than 2dB rise at 125Hz at a height of 1.2m due to room modes.

• 실천공학교육논문지
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• 제10권2호
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• pp.119-124
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• 2018

IMU(Inertial Measurement Unit) 센서의 가속도와 각속도를 이용하여 거리측정을 하고 측정값을 이용하여 사용자가 원하는 실내공간에 적용하여 사용자 혹은 디바이스가 실내공간을 인식하는 교육용 장비를 소개한다. 본 교육장비를 이용해서 다양한 위치 인식 및 추적 알고리즘을 학습할 수 있고 창의적 공학설계 작품을 구현할 수 있다. IMU 센서의 데이터 값을 $I^2C$(Inter-Integrated Circuit)을 통해 MCU(microcontroller unit)에 전송하고 필터와 연산방식을 통해 데이터 값을 처리 후 실내 위치 인식 알고리즘을 통해 위치인식을 한다. 그리고 무선통신을 이용하여 처리된 값을 송수신하여 사용자가 인식하도록 설계한다. 본 교육 장비를 이용하여 "IMU센서를 이용하여 이동거리를 산출과 데이터 값을 이용한 가상공간 구현 및 인식"의 사례를 소개하고 그 설계를 기반하여 다양한 창의적 공학설계 적용에 대해서 논한다.

• 한국해양공학회지
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• 제12권2호통권28호
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• pp.121-129
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• 1998

A quantitative non-contact multi-point measurement system is proposed to the measurement of three-dimensional movement of floating vessels by using digital image processing. The instantaneous three-dimensional movement of a floating structure which is floating in a small water tank is measured by this system and its three-dimensional movement is reconstructed by the measurement results. The validity of this system is verified by position identification for spatially distributed known positional values of basic landmarks set for the camera calibration. It is expected that this system is applicable to the non-contact measurement for an unsteady physical phenomenon especially for the measurement of three-dimensional movement of floating vessels in the laboratory model test.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.619-625
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• 1997

In this paper, we show that the rotor position of the bifilar-wound hybrid stepping motors for the closed-loop drives is detected by the phase current measurement. We propose an instantaneous phase current equation, which is the function of electrical angle, by modeling the stepping motor including motor driving circuits. We also analyze the relationship between phase current and rotor position from the computer simulation results. We show that the information about the rotor position is obtained from the phase current amplitude and its derivatives at the instance of ${\pi}/2$ electrical angle of excitation voltage.

• 드라이브 ㆍ 컨트롤
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• 제17권4호
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• pp.8-14
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• 2020

Intelligent devices using ICT technology have been introduced in the field of construction machinery to improve productivity and stability. Among the intelligent devices, Machine Guidance is a device that provides real-time posture, location, and work range to drivers by installing various sensors, controllers, and satellite navigation systems on construction machines. Conversely, the efficiency of equipment that requires location information, such as machine guidance, will be greatly reduced in buildings, and tunnels in the GPS blind spots. Thus, the other high-precision positioning technologies are required in the GPS blind spot zone. In this study, we will develop a relative position measurement system that provides precise location information such as construction machinery and robots in a local area where the GPS reception is difficult. A relative position measurement system tracks a marker in the form of a sphere installed on a vehicle by using the image base tracking technology, and measures the distance and direction information to the marker to calculate a position.