• 제어로봇시스템학회논문지
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• 제20권8호
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• pp.807-814
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• 2014

In this paper, we proposed a haptic navigation system which used the tactile data for the user guides of the mobile robot to the reference point via tele-operation in unknown blind environment. This navigation system can enable a mobile robot to avoid obstacles and move to the reference point, according to the direction provided by the device guides through a haptic device consisting of a vibration motor in a blind environment. There are a great deal of obstacles in real environments, and so mobile robots can avoid obstacles by recognizing the exact position of each obstacle through the superposition of an ultrasonic sensor. The navigation system determines the direction of obstacle avoidance through an avoidance algorithm that uses virtual impedance, and lets users know the position of obstacles and the direction of the avoidance through the haptic device consisting of 5 vibration motors. By letting users know intuitionally, it lets the mobile robot precisely reach the reference point in unknown blind environment. This haptic device can implement a haptic navigation system through the tactile sensor data.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.23.1-23
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• 2001

The unmanned vehicle is composed of three parts the front & side sensor system for keeping the lane and avoiding obstacles, the acceleration & brake control system for longitudinal motion control, and the steering control system for the lateral motion control. Each system helps the unmanned vehicle of which should take notice of its location and recognize obstacles around the place by itself and make a decision how much fast to proceed according to circumstances. During the operation, the control strategy that the vehicle can detect obstacles and avoid collision on the road involves with vehicle velocity very much. Therefore, We have to define a traction system which is powered by DC motor so that, unmanned vehicle can control its velocity accurately. In this study, we find mechanical and ...

• 한국건축시공학회지
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• 제20권4호
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• pp.375-382
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• 2020

국내 국경 지역의 주요 도로에 낙석 장애물을 설치, 운영하여 적군의 이동을 방지하고 차단하고 있다. 그러나 접경지역의 개발로 인한 교통량 증가는 낙석으로 인한 도로 교통 혼잡, 교통 안전, 도시 미관 저하 등 많은 문제를 야기하고 있다. 따라서 본 연구는 단위별로 다르게 적용되는 낙석장해물 철거 및 교체 시설 설치 지침을 제공하고, 운영에 필요한 낙석 장해물 유지비에 대한 국방부의 정책 방향을 제시하고자 하였다. 본 연구에서는 낙석 장해물 제거 및 대체시설 설치에 관한 지침 연구의 일환으로 필수 낙하 장해물에 대한 표준 단가를 제시하여 암석 제거 여부를 판단 할때 판단 자료로 활용하고자 하였다.

• Journal of Biosystems Engineering
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• 제21권2호
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• pp.167-174
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• 1996

A Fuzzy Logic Controller(FLC) was developed for the autonomous operation of speedsprayer in an orchard. The autonomous operation with the FLC was graphically simulated under the real condition of the orchard. Image processing was used to find out the direction of running and four ultrasonic sensors were used to detect obstacles for the running. The simulation results showed that the speedsprayer could be operated autonomously with the FLC combined with the image processing and the ultrasonic sensors.

• Journal of Biosystems Engineering
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• 제23권1호
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• pp.75-82
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• 1998

Autonomous speedsprayer operation was conducted using a fuzzy controller combined with a DGPS. The signal of DGPS receiver and signals of four ultrasonic sensors were processed in real time. The speedsprayer was steered with two levers controlled by two hydraulic cylinders. The fuzzy controller has two inputs; direction of running obtained from the DGPS receiver and distance from trees measured by ultrasonic sensors. The operation times of the hydraulic cylinders were inferred as outputs of the fuzzy controller. Field test results showed that the speedsprayer could be autonomously operated by the developed fuzzy controller including turning operation in the end of the tree row. The ultrasonic sensors contributed a little to performance of the autonomous operation, but the speedsprayer could avoid trees or obstacles in emergent situations with them.

• 한국식품조리과학회지
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• 제23권2호통권98호
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• pp.195-204
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• 2007

The objective of this study was to analyze dietitians' sanitary practices and perceptions of obstacles according to HACCP. Questionnaires were administered to 94 elementary school dietitians in the Gwangju and Jeonnam Regions of South Korea. The data were evaluated by a 5 scale Likert method and statistically analyzed The results of the study are as follows. Each subject was generally characterized as a university graduate 79.8%, with 10 to 15 years experience 37.6%, and in her mid to late thirties 39.4%. We found that direct management was the highest occurring form of food service system 96.8%. With regards to the type of food service operation quantitative service as 60.6%, and partial self-service was 30.9%, 89.4%of all served only lunch. In all, 93.6% of the teams collaborated, while their organic collaboration was 64.9%. When HACCP was applied, sanitary practices scored an average of 4.83, which was significantly higher than 4.62 when HACCP was not applied. The dietitians' perception of sanitary practices was as very high 4.75 of 5. Sanitation, in regards to food management, scored 4.89 among the detailed items. This proves that in relation to food management, sanitation is considered most important. When HACCP was not applied, the perception of obstacles was, on an average, 3.07, which was higher than 2.74 when HACCP was applied. The results for the detailed items, which focused on sanitary practices and different perceptions of obstacles according to HACCP, were as follows. When HACCP was applied, a high mean of 3.32 occurred for facilities and utilities shortages followed by degree of cooperation at 3.22, and then monitoring at 3.01. The item that dietitians viewed as the biggest obstacle was lack of departmental budget support (M=3.46). Other serious obstacles were facilities, facility sanitation, and utility shortages (M=3.38), as well as the aappropriateness of machines and cooking utensils and arrangements in the dining room (M=3.28). Stepwise multiple regression was used to better understand how much these perceptions of obstacles would influence sanitary practices when HACCP was applied. The item analysis of the HACCP obstacles proved that persons involved in food service, except the food service employees, didn't cooperate enough with their food service employees. As a result, this lack of cooperation had a negative effect on sanitary practices. Accordingly, it is necessary to determine the causes of for lack of cooperation and attract the active attention of those involved.

• 전기학회논문지
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• 제64권4호
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• pp.586-591
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• 2015

This paper proposes a force feedback system of telepresence robot for remote operation. The ultrasonic sensors attached at the robot detect the obstacles, and generate the force to the operation joystick. In order to consider the network delay, we developed the fuzzy control system using ultrasonic data and robot speed. The method to calculate the force vector from the ultrasonic data is also presented to operate the robot more accurately. The simulation and experimental results are presented to verify the safe and accurate operation of the proposed system.

• 한국CDE학회논문집
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• 제20권3호
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• pp.298-311
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• 2015

Nowadays, automatic digging operation of an excavator is a big challenge due to the complexity of digging environment, the hardness of soil and buried obstacles into the ground. In order to achieve the maximum soil bucket volume, this paper introduces a novel engineering model that was developed as a virtual excavator in the design phase. Through this model, the designs of mechanical and control systems for autonomous excavator are executed and modified easily before developing in real testbed. Based on a concept of an autonomous excavation, a mechanical system of excavator was first designed in SOLIDWORKS, and a soil model also was modeled by finite-element analysis in ANSYS, both modeled models were then exported to ADAMS environment to investigate the digging behavior through virtual simulation. An intelligent control strategy was generated in MATLAB/Simulink to control the excavator operation. The simulation results were demonstrated by effectiveness of the proposed excavator robot in testing scenarios with many soil types and obstacles.

• 한국안전학회지
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• 제28권4호
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• pp.19-25
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• 2013

For safe remote control, information on remote environment has to be delivered to operator realistically, and there have been numerous research efforts on this respect. Among them, haptic technology can significantly enhance safety and overall effectiveness of remote operation by delivering various kinds of information on virtual or real environment to operator. In this study, remote control based on haptic feedback is applied to control of mobile robot moving according to the command from operator avoiding collision with environmental obstacles and maintaining safe distance from them using ultrasonic sensors. Specifically, a remote feedback control structure for mobile robot is proposed. The controller is based on the inner feedback loop that directly utilizes information on distance to obstacles, and the outer feedback loop that the operator directly commands using the haptic device on which the computed reaction force based on the distance information is acting. Effectiveness of the proposed remote control scheme using double feedback loops is verified through a series of experiments on mobile robot.

• 제어로봇시스템학회논문지
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• 제22권11호
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• pp.904-911
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• 2016

This paper presents a novel driving system by the humanoid robot to drive a vehicle in disaster response situations. To enhance robot's capability for substituting human activities in responding to natural and man-made disaster, the one of prerequisite skills for the rescue robot is the mounted mobility to maneuver a vehicle safely in disaster site. Therefore, our driving system for the humanoid is developed in order to steer a vehicle through unknown obstacles even under poor communication conditions such as time-delay and black-out. Especially, the proposed system includes a tele-manipulation interface and stable navigation strategies. First, we propose a new type of path estimation method to overcome limited communication. Second, we establish navigation strategies when the operator cannot recognize obstacles based on Dynamic Window Approach. The effectiveness of the proposed developments is verified through simulation and experiments, which demonstrate suitable system for driving a vehicle in disaster response.