• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1845-1848
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• 2005

The automatic $CO_2$ welding is a manufacturing process to produce high quality joints for metal and it could provide a capability of full automation to enhance productivity. Despite the widespread use in the various manufacturing industries, the full automation of the robotic $CO_2$ welding has not yet been achieved partly because the mathematical model for the process parameters of a given welding task is not fully understood and quantified. Several mathematical models to control welding quality, productivity, microstructure and weld properties in arc welding processes have been studied. However, it is not an easy task to apply them to the various practical situations because the relationship between the process parameters and the bead geometry is non-linear and also they are usually dependent on the specific experimental results. Practically, it is difficult, but important to know how to establish a mathematical model that can predict the result of the actual welding process and how to select the optimum welding condition under a certain constraint. In this research, an attempt has been made to develop an intelligent algorithm to predict the weld geometry (top-bead width, top-bead height, back-bead width and back-bead height) as a function of key process parameters in the robotic $CO_2$welding. A sensitivity analysis has been conducted and compared the relative impact of three process parameters on bead geometry in order to verify the measurement errors on the values of the uncertainty in estimated parameters.

• Journal of Animal Science and Technology
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• 제45권6호
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• pp.1079-1088
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• 2003

축산기술연구소에서 개발한 액상사료 자동급이기의 성능을 검사하고 이를 이용하여 조기 이유자돈의 사육 가능성을 알아보기 위하여 본 연구를 실시하였다. 포유중인 자돈 60두를 공시하여 대조구 자돈들은 21일령 까지 모돈에게 포유시켰다. 나머지는 생후 7일령에 모돈으로 부터 이유시킨 다음 액상사료 자동급이기를 이용하여 21일령까지 액상사료를 자동으로 인공급여 하였다. 그 이후 모든 자돈을 70일령 까지 단계적으로 같은 가루사료를 급여하였다. 그리고, 미국으로부터 수입되어 사용되고 있는 액상사료 자동급이기를 새로이 개발한 액상사료 자동급이기와 비교하여 사용하였다. 자돈들의 성장과 사료이용, 그리고 설사발생과 소장의 융모 변화 등을 조사하였다. 그 결과는 다음과 같다. 생후 7일에 모돈으로 부터 이유한 다음 액상사료 자동급이기를 이용하여 액상사료를 급여한 자돈들의 21일령 체중은 모두 포유를 지속한 자돈들에 비해 모두 유의하게(P〈0.05) 낮았다(5.55 vs 4.97 & 4.98 kg/head). 그 이후 액상사료 급여 자돈들의 성장이 빨라 70일령에 이르러서는 체중이 모돈으로 부터 포유하였던 자돈들에 비해 오히려 유의적으로(P〈0.05) 증가하는 결과를 보여 주었다(24.82 vs. 30.17 & 29.42 kg/head). 시험 전기간 동안의 일당증체량은(346.7 vs 425.8 & 416.1g/head) 모돈으로 부터 포유한 자돈보다 인공 포유 자돈들이 유의하게 증가하였다(P〈0.05). 사료요구율은 시험 전기간 동안 차이가 없었다(1.67 vs 1.78 and 1.84). 자돈들의 설사발생 빈도에 있어 액상사료 자동급이기 간에 차이가 없었다. 소장의 융모 변화를 비교한 결과 액상사료 인공포유 3일째(10일령) 십이지장 융모 높이가 크게 낮아진 것으로 나타났으나 7일째(14일령) 부터 융모가 회복되는 것으로 나타났다. 공장의 융모높이는 7일째(14일령) 크게 낮아진 것으로 나타났으나 14일째(21일령) 부터 융모가 회복되는 것으로 나타났다. 회장의 융모 높이는 처리간에 어떠한 경향을 보이지 않았다. 축산기술연구소에서 개발한 액상사료 자동급이기(NLRI)와 수입한 액상사료 자동급이기(IALF)에서 자돈 성장의 차이는 보이지 않았다. 이상의 결과 새로이 개발한 NLRI로 생후 7일만에 조기이유 시킨 자돈들도 성공적으로 육성할 수 있음을 보여주었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1202-1205
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• 2005

This paper describes a method for vision-based person identification that can detect, track, and recognize person from video using multiple cues: height and dressing colors. The method does not require constrained target's pose or fully frontal face image to identify the person. First, the system, which is connected to a pan-tilt-zoom camera, detects target using motion detection and human cardboard model. The system keeps tracking the moving target while it is trying to identify whether it is a human and identify who it is among the registered persons in the database. To segment the moving target from the background scene, we employ a version of background subtraction technique and some spatial filtering. Once the target is segmented, we then align the target with the generic human cardboard model to verify whether the detected target is a human. If the target is identified as a human, the card board model is also used to segment the body parts to obtain some salient features such as head, torso, and legs. The whole body silhouette is also analyzed to obtain the target's shape information such as height and slimness. We then use these multiple cues (at present, we uses shirt color, trousers color, and body height) to recognize the target using a supervised self-organization process. We preliminary tested the system on a set of 5 subjects with multiple clothes. The recognition rate is 100% if the person is wearing the clothes that were learned before. In case a person wears new dresses the system fail to identify. This means height is not enough to classify persons. We plan to extend the work by adding more cues such as skin color, and face recognition by utilizing the zoom capability of the camera to obtain high resolution view of face; then, evaluate the system with more subjects.

• 대한인간공학회지
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• 제6권2호
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• pp.19-28
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• 1987

If an error occurs in the automatic mode when the advanced teleoperator system performs a task in hostile environment, then the mode changes into the manual mode. The operation by program and the operation by hyman recover the error in the manual mode. The system resumew the automatic mode and continues the given task. In order to utilize the inverse kinematics as means of the operation by program in the manual mode, Lee and Nagamachi determined the end point of the robot trajectory planning which varied with the height of the task object recognized by a T.V monitor, solved the end point by the fuzzy set theory, and controlled the position of the robot hand by the inverse kinematics and the posture of the robot hand by the operation by human. But the operation by human did take a lot of task time because the position and the posture of the robot hand were separately controlled. To reduce the task time by human, this paper developes an error recovery expert system (ERES). The position of the robot hand is controlled by the inverse kinematics of the cartesian coordinate system to the end point which is deter- mined by the fuzzy set theory. The posture of the robot hand is controlled by the modulality of the robot hand's motion which is made by the posture of the task object. The knowledge base and the inference engine of the ERES is developed using the muLISP-86 language. The experimental results show that the average task time by human the ERES which was performed by the integration of the position and the posture control of the robot hand is shorter than that of the research, done by the preliminary experiment, which was performed by the separation of the position and the posture control of the robot hand. A further study is likely to research into an even more intelligent robot system control usint a superimposed display and digitizer which can present two-dimensional coordinate of the work space for the convenience of human interaction.

• Journal of Biosystems Engineering
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• 제36권1호
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• pp.9-14
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• 2011

This study was carried out to develop a vine crusher for harvesting sweet potato. The experimental two-row vine crusher attachable to agricultural tractor composed of vine crushing part with frail type vine crushing blades and vine lifting blades, power transmission part with chain and gear transmission mechanism, crushing height control part with two control wheels and manual levers, and implement frames, was designed and fabricated. And this vine crushing performance was also analyzed. From vine crushing tests, backward travel direction (i.e., rotational direction of the vine crushing blades) showed better vine crushing performance than forward travel direction. Crushing ratio of remained vine was increased, and length of remained vine and length of crushed vine were decreased as working speed was decreased and rotational speed of vine crushing blades was increased. At a working speed of 0.27 m/s and rotational speed of vine crushing blades of 800 rpm, crushing ratio of remained vine was 98%, length of remained vine was 104 mm, and length of crushed vine was 327 mm. But, when crushing vine on irregular ridges, vines and mulching vinyl were wound in the vine crushing part. Therefore, change of location of power transmission chain mechanism, and an automatic control device for controlling crushing height were needed.

• 대한공간정보학회지
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• 제15권4호
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• pp.103-109
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• 2007

고해상도 위성영상으로부터 수치고도자료와 정사영상을 생성하기 위해서는 센서모델을 수립해야 한다. 센서모델 수립에 필요한 지상기준점은 실측을 통해서 획득할 수 있지만, 이를 위해서는 많은 시간과 비용이 소요된다. 본 연구에서는 기존의 정사영상과 위성영상 간의 정합을 통해서 얻은 지상좌표와 그에 대응하는 높이를 Digital Terrain Elevation(DTED) Level 2 자료로부터 추출하여 IKONOS 위성영상 센서모델을 수립하기 위한 기준점을 획득하였다. 획득한 기준점으로 IKONOS 센서 모델을 수립하고 그 결과를 분석하여 이로부터 추출한 기준점이 IKONOS 위성영상의 센서모델 수립에 적합한지 여부를 알아보았다. 본 연구를 위해서 사용된 DTED Level 2는 공간해상도가 약30m이고, 절대 수평 정확도는 원형오차로 23m(WGS84 기준)이하이고 절대 수직 정확도가 평균해수면 기준으로 18m 이하인 수치고도모델이다. 정합에 사용된 기존 정사영상의 공간해상도는 1m이다. 본 연구에서는 DTED와 정사영상을 이용해서 추출한 기준점으로 수립한 IKONOS 센서모델의 성능을 분석하였다. 실측 기준점을 검사점으로 했을 때 수립된 모델의 독립적 성능은 약 $4{\sim}5$ 픽셀 정도였다. 또한 수치고도모델을 생성하고 이를 실측 기준점으로 생성한 수치고도모델과 육안으로 비교했을 때 서로 유사함을 알 수 있었으며, DTED 자료를 기준으로 산출한 높이 RMS 오차는 약 9 m였다. 이 결과로 보아 DTED Level 2와 정사영상을 이용해서 추출한 기준점이 IKONOS 센서 모델 수립에 적용될 수 있음을 알 수 있었다.

• 한국정밀공학회지
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• 제15권8호
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• pp.17-25
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• 1998

Aluminum alloys have low density, relatively high strength and yield strength, good plasticity, good machinability, and high corrosion and acid resistance. Therefore, they are suitable for large containers for the food, chemical and other industries. Large containers are often bodies of revolution consisting of shell courses, stiffening rings, heads and other elements joined by annular welds. Larger containers have longer welds and require greater leak-tightness and higher weld mechanical properties. The LNG tank consists of aluminum plates with various sizes, so its construction should by divided by several sections. Moreover, each section has its own sub-section consisted of several aluminum plates. To guarantee the quality of huge LNG tank, therefore, the precise control of plate dimension should by urgently needed in conjunction with the appropriate selection of process parameters such as cutting speed, depth of cut, rotational speed and so on. In this paper, a manufacturing system was developed to implement automatic circular tracking in height direction and automatic circular interpolation in depth of cut direction. Also, the neural network based on the backpropagation algorithm was used to predict the cutting quality and motor load related with the life time of the developed system. It was revealed that the manufacturing system and the neural network could be effectively applied to the bevelling process and to predict the quality of machined area and the motor load.

• 한국농공학회논문집
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• 제46권5호
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• pp.3-11
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• 2004

The objective of this study is to develop water saving irrigation method using water balance model in order to save rural water. Daily water balance components such as irrigation water, drainage water, effective rainfall, ET, and infiltration were measured in paddy fields. Model simulations were performed for different outlet heights and ponding depths. The outlet heights and the ponding depths are 2 cm, 4 cm, 6 cm, 8 cm, and 10 cm, respectively. Based on the simulation very shallow ponding depth of 2 cm with 10 cm outlet height showed the largest effective rainfall ratio and the smallest irrigation amount. Until the introduction of laser leveling dozer and automatic inlet control devices, it would be desirable to adopt 4cm ponding depth because of difficulty of land leveling and frequency of farmer's field visit. The results of this study will be applied in the paddy farming and can improve water use efficiency.

• 한국의류학회지
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• 제28권6호
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• pp.790-794
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• 2004

The study is about practical use of the computer program developed to obtain more efficient and accurate photographic measurement of body. Measuring measurements automatically using this program, the observational errors can be reduced considerably, so that the accuracy of photographic measurement are improved. The program has several functions as follow; First, free rotation of body by horizontal and perpendicular control of photo data. Second, recognition of body outline of photo data and automatic measuring of 45 basic items as well as freehand measuring of height, width, depth, angle. Third, obtaining database of photographic measurements of each subject without additional process such as data input.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 추계학술대회 논문집
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• pp.141-148
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• 1994

In order to improve the productivity of cold forging at low production cost, an integrated system's approach is necessary in handling the material preparation and the optimum process design, considering the forming machines, tooling, and operation including quality control. As the first step toward this approach, an expert system for multi-stage cold forging process design for fasteners with various head geometries is developed using Prolog language on IBM 486 PC. For effective representation of the complex part geometries, the system uses the multiple element input, and the forward inference scheme in determination of the initial billet size and intermediate forging steps. In order to determine intermediate steps, the basic empirical rules for extrusion, heading, and trimming were applied. The required forming loads and global strain distributions at each forging step were calculated and displayed on the PC monitor. The designed process sequence drawing can be obtained by AutoCAD. The developed system will be useful in reducing trial and error of design engineers in determining the diameter and height of the initial cylindrical billet from the final product geometry and the intermediate necessary sequences.