• 농업과학연구
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• 제42권1호
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• pp.63-71
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• 2015

Path planning is an essential part for traveling and mowing of autonomous lawn mower tractors. Objectives of the paper were to analyze operation patterns by a skilled farmer, to extract and optimize waypoints, and to demonstrate generation of formatted planned path for autonomous lawn mower tractors. A 27-HP mower tractor was operated by a skilled farmer on grass fields. To measure tractor travel and operation characteristics, an RTK-GPS antenna with a 6-cm RMS error, an inertia motion sensing unit, a gyro compass, a wheel angle sensor, and a mower on/off sensor were mounted on the mower tractor, and all the data were collected at a 10-Hz rate. All the sensor data were transferred through a software program to show the status immediately on the notebook. Planned path was generated using the program parameter settings, mileage and time calculations, and the travel path was plotted using developed software. Based on the human operation patterns, path planning algorithm was suggested for autonomous mower tractor. Finally path generation was demonstrated in a formatted file and graphic display. After optimizing the path planning, a decrease in distance about 13% and saving of the working time about 30% was achieved. Field test data showed some overlap, especially in the turning areas. Results of the study would be useful to implement an autonomous mower tractor, but further research needs to improve the performance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.1-6
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• 1992

An autonomous mobile robot has been developed which can follow a travel map drawn on a monitor screen using a software. The robot works as an exhbition guide making announcement regrading the events to take place or introducing the products on display. This mobile robot computes the world position and heading direction through camera image, ultrasonic and infrared sensors in real time using specially designed algorithm. This mobile robot will be exhibited at '93 Tae-Jeon EXPO for an exhibition guide, and will be used in a plant or a hospital for materials handling purposes.

• Agricultural and Biosystems Engineering
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• 제6권2호
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• pp.47-53
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• 2005

AMachine vision is a promising tool for the autonomous guidance of farm machinery. Conventional CCD camera for the machine vision needs a desktop PC to install a frame grabber, however, a web camera is ready to use when plugged in the USB port. A web camera with a notebook PC can replace existing camera system. Autonomous steering control system of this research was intended to be used for combine harvester. If the web camera can recognize cut/uncut edge of crop, which will be the reference for steering control, then the position of the machine can be determined in terms of lateral offset and heading angle. In this research, a white line was used as a cut/uncut edge of crop for steering control. Image processing algorithm including capturing image in the web camera was developed to determine the desired travel path. An experimental vehicle was constructed to evaluate the system performance. Since the vehicle adopted differential drive steering mechanism, it is steered by the difference of rotation speed between left and right wheels. According to the position of vehicle, the steering algorithm was developed as well. Evaluation tests showed that the experimental vehicle could travel within an RMS error of 0.8cm along the desired path at the ground speed of $9\sim41cm/s$. Even when the vehicle started with initial offsets or tilted heading angle, it could move quickly to track the desired path after traveling $1.52\sim3.5m$. For turning section, i.e., the curved path with curvature of 3 m, the vehicle completed its turning securely.

• 제어로봇시스템학회논문지
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• 제11권5호
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• pp.429-434
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• 2005

In this paper, the maze navigation system using image recognition for autonomous mobile robot is proposed. The proposed maze navigation system searches the target by image recognition method based on ADALINE neural network. The infrared sensor system must travel all blocks to find target because it can recognize only one block information each time. But the proposed maze navigation system can reduce the number of traveling blocks because of the ability of sensing several blocks at once. Especially, due to the simplicity of the algorithm, the proposed method could be easily implemented to the system which has low capacity processor.

• Journal of Biosystems Engineering
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• 제27권5호
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• pp.417-424
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• 2002

This study was conducted to develop a vehicle, leading or following a worker at a certain distance to assist laborious transporting works in greenhouses. A prototype vehicle was tested in the practical field conditions using a developed control algorithm. Results of this study were summarized as following: 1. The sensing device consisted of infrared sensors was attached to the front of the vehicle and turning following algorithm was developed to make the vehicle turned as it follows a worker simultaneously. 2. The measured average power consumptions were 110W and 89W, equivalent to 5.2-6.4 hrs battery durations, at low speed with and without the maximum payload, respectively. 3. Results of the travel tests showed that the deviations from the center of row spacing were $\pm$100 mm along the ridge and $\pm$85 mm along the hydroponic bed in the greenhouse. Therefore, the worker-following transport vehicle was feasible to travel along the row without collision in the greenhouse.

• Journal of Biosystems Engineering
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• 제27권5호
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• pp.409-416
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• 2002

This study was conducted to develop a vehicle, leading or following a worker at a certain distance to assist laborious transporting works in greenhouses. A prototype vehicle, which consisted of the rear driving, the front steering and the console units, was designed and tested in the ideal indoor conditions. Results of this study were summarized as following: 1. The driving unit was designed to travel at the speed ranges of 0.3∼0.8 m/sec depending on the operating modes with a maximum payload of 100 kg. 2. The console unit consisted of a main-board including a 80C196KC microprocessor and peripheral devices, a power-board and safety interlock. Worker-leading, and following modes were available in automatic and manual modes. 3. Steering was achieved by turning the steering motor against the sensed direction. Proper steering angles for correcting travel direction were determined as 5 and 9 degrees when sensing cultivation beds and plants, respectively.

• Journal of Biosystems Engineering
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• 제26권1호
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• pp.29-38
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• 2001

A navigation system was developed for autonomous guidance of a combine. It consisted of a DGPS, a machine vision system, a gyro sensor and an ultrasonic sensor. For an autonomous operation of the combine, target points were determined at first. Secondly, heading angle and offset were calculated by comparing current positions obtained from the DGPS with the target points. Thirdly, the fuzzy controller decided steering angle by the fuzzy inference that took 3 inputs of heading angle, offset and distance to the bank around the rice field. Finally, the hydraulic system was actuated for the combine steering. In the case of the misbehavior of the DGPS, the machine vision system found the desired travel path. In this way, the combine traveled straight paths to the traget point and then turned to the next target point. The gyro sensor was used to check the turning angle. The autonomous combine traveled within 31.11cm deviation(RMS) on the straight paths and harvested up to 96% of the whole rice field. The field experiments proved a possibility of autonomous harvesting. Improvement of the DGPS accuracy should be studied further by compensation variations of combines attitude due to unevenness of the rice field.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권5호
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• pp.307-314
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• 2005

In this paper, we propose a predictive system for the avoidance of the moving obstacle. In the dynamic environment, robots should travel to the target point without collision with the moving obstacle. For this, we need the prediction of the position and velocity of the moving obstacle. So, we use the Kalman filer algorithm for the prediction. And for the application of the Kalman filter algorithm about the real time travel, we obtain the position of the obstacle which has the future time using Fuzzy system. Through the computer simulation studies, we show the effectiveness of the proposed navigational algorithm for autonomous mobile robots.

• 한국지능시스템학회논문지
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• 제26권2호
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• pp.105-112
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• 2016

본 논문은 대학 캠퍼스를 주행하는 차량의 자율주행을 위한 실험환경 구축에 대해 논한다. 이 차량은 대학이나 공원과 같은 특별한 장소에서 사용되고 근거리를 이동하기 위해 2인이 탑승한다. 정문에서 본부까지 자율주행을 수행하기 위한 실험환경을 구축한다. 초기 단계로 카메라로 바닥의 색깔을 구별하여 선을 검출한다. 빨간색과 노란색의 경계선을 검출하여 로봇차량이 추종할 수 있도록 하였다. 일부 구간의 자율 주행 실험을 통해 가능성을 검증하였다.

• Journal of Biosystems Engineering
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• 제33권1호
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• pp.51-57
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• 2008

The purpose of this study was to develop an optimal path planning program for autonomous speed sprayer in orchard. A digital map which contained coordinate information and entity information including height, width, radius of main stem, and disease of a trees was developed to build an optimal path. The digital map, dynamic programming and order-picking algorithm were used for planning an optimal path for autonomous speed sprayers. When this algorithm applied to rectangular-shaped orchards to travel whole trees, the developed program planned the same working path and same traveling distance as those of created by conventional method. But for irregular-shaped orchards, developed program planned differently and 5.06% shorter path than conventional method. When applied to create path for multi-selected trees, irregular-shaped orchards showed 13.9% shorter path and also rectangular-shaped orchards showed 9.1% shorter path. The developed program always planned shorter path than the path created by conventional method despite of variation of shape of orchards.