• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2015-2018
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• 2005

Obstacle avoidance is a basic skill to make a mobile robot move effectively and safely even in any arbitrarily given environment. Because of the difficulty of self-location caused by unavoidable slip and drift errors of sensors and effective detection of any encountered obstacle, only finite and simple obstacle avoidance strategies can be carried out. In this paper we mainly explored how to make a robot perform effectively obstacle detection and avoidance in the guideline navigation with one CCD video camera and some supersonic sensors. Making use of the specially designed guideline, the detection and calculation of the geometric dimensions of the encountered obstacle became simpler. And possible avoidance strategies appropriate to our navigation were studied and the simulations results were given.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.183-192
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• 2003

Obstacle detection and avoidance are considered as one of the key technologies on an unmanned vehicle system. In this paper, we propose a method of obstacle detection and avoidance and it is composed of vehicle control, modeling, and sensor experiments. Obstacle detection and avoidance consist of two parts: one is longitudinal control system for acceleration and deceleration and the other is lateral control system for steering control. Each system is used for unmanned vehicle control, which notes its location, recognizes obstacles surrounding it, and makes a decision how fast to proceed according to circumstances. During the operation, the control system of the vehicle can detect obstacles and perform obstacle avoidance on the road, which involves vehicle velocity. In this paper, we propose a method for vehicle control, modeling, and obstacle avoidance, which are evaluated through road tests.

• Agricultural and Biosystems Engineering
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• 제2권2호
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• pp.69-74
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• 2001

Detection of operation lines in farm works, object recognition and obstacle avoidance are essential pre-requisite technologies for unmanned agricultural machinery. A CCD camera, which has been largely used for these functions, is expensive and has difficulty in real-time signal processing. In this study, a laser range sensor was selected as the guiding vision for unmanned agricultural machinery such as a tractor. To achieve this capability, algorithms for distance measurement, signal filtering, object recognition, and obstacle avoidance were developed. Computer simulations were carried out to evaluate performance of the algorithms. Experiments were also conducted with various materials and shapes, Laser beam lost its intensity for poor reflective materials, resulting in less range value than actual, so a compensation technique was considered to be necessary. Object detection system was fabricated on an agricultural tractor and the performance was evaluated. As test result for obstacle detection and avoidance in field, to detect and avoid obstacle for path finding with guiding system for unmanned agricultural machinery was enable.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1999년도 추계학술대회논문집
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• pp.315-320
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• 1999

Obstacle Detection System(ODS) is a essential system for automated vehicle, such as AGV(Automatic Guided Vehicle), mobile robot. Automated vehicle must have a capability to detect and to avoid obstacles to guarantee a safe driving condition. To implement obstacle detection system, virtual bumper concept adapted. Like real bumper in a car, such as in the truck, it protects vehicle from collision using laser distance sensor. When an obstacle(such as other vehicle, building, etc) intrudes this virtual bumper area, a virtual force is calculated and produces necessary strategy to be able to avoid collision. In this paper, simplified virtual bumper concept is presented, and various problems when happens to implement are discussed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2019년도 춘계학술대회
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• pp.195-196
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• 2019

현재 개발 중인 자율주행 선박의 안전한 자율주행 운항 안전성을 확보하기 위하여 COLREG를 바탕으로 하는 다중 장애물회피 알고리즘을 연구하였다.RADAR에서 제공하는 외부 장애물의 VECTOR 값을 활용하여 각 장애물의 CPA와 TCPA를 분석하여 기 값을 기준으로 장애물을 구분하고 다중 장애물 회피 상황을 고려한 위험도 산정하였고 최소한의 안전 상황을 확보하기 위한 회피 동작 적용 방법에 관한 연구를 하였다.

• 제어로봇시스템학회논문지
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• 제22권4호
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• pp.253-265
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• 2016

We propose an obstacle classification method using multi-decision factors and decision sections based on Single 2D LiDAR. The existing obstacle classification method based on single 2D LiDAR has two specific advantages: accuracy and decreased calculation time. However, it was difficult to classify obstacle type, and therefore accurate path planning was not possible. To overcome this problem, a method of classifying obstacle type based on width data was proposed. However, width data was not sufficient to enable accurate obstacle classification. The proposed algorithm of this paper involves the comparison between decision factor and decision section to classify obstacle type. Decision factor and decision section was determined using width, standard deviation of distance, average normalized intensity, and standard deviation of normalized intensity data. Experiments using a real autonomous vehicle in a real environment showed that calculation time decreased in comparison with 2D LiDAR-based method, thus demonstrating the possibility of obstacle type classification using single 2D LiDAR.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권1호
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• pp.82-86
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• 2008

The article presents ARTMAP and Fuzzy BK-Product approach underwater obstacle avoidance for the Autonomous underwater Vehicles (AUV). The AUV moves an unstructured area of underwater and could be met with obstacles in its way. The AUVs are equipped with complex sensorial systems like camera, aquatic sonar system, and transducers. A Neural integrated Fuzzy BK-Product controller, which integrates Fuzzy logic representation of the human thinking procedure with the learning capabilities of neural-networks (ARTMAP), is developed for obstacle avoidance in the case of unstructured areas. In this paper, ARTMAP-Fuzzy BK-Product controller architecture comprises of two distinct elements, are 1) Fuzzy Logic Membership Function and 2) Feed-Forward ART component. Feed-Forward ART component is used to understanding the unstructured underwater environment and Fuzzy BK-Product interpolates the Fuzzy rule set and after the defuzzyfication, the output is used to take the decision for safety direction to go for avoiding the obstacle collision with the AUV. An on-line reinforcement learning method is introduced which adapts the performance of the fuzzy units continuously to any changes in the environment and make decision for the optimal path from source to destination.

• 한국철도학회논문집
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• 제20권2호
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• pp.173-181
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• 2017

장애물제거기는 선로 내 장애물에 의한 충돌사고 발생 시 장애물을 선로 밖으로 밀어내거나 에너지흡수부재를 통해 충돌에너지를 흡수하여 열차 탈선을 방지하고 충돌사고에 의한 피해를 최소화하기 위한 장치이다. 본 연구에서는 인장형 에너지흡수부재와 4절 링크를 이용하여 장애물제거기의 작동 메커니즘을 구성하여 장애물제거기를 설계하였다. 또한 EN 15227에서 요구하는 정적강도 및 에너지흡수조건을 확인하기 위한 성능검증시험 방법을 고안한 뒤 유한요소해석 및 UTM (Universal Test Machine)을 이용한 성능검증시험을 수행하였다. 본 연구를 통해 EN 15227의 요구조건을 만족하는 장애물제거기를 개발하였으며, 제안된 장애물제거기의 설계 및 검증 절차에 따라 붕괴하중의 조절이 가능하며 이를 실험을 통해 검증할 수 있는 방법을 제안하였다.

• Journal of Platform Technology
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• 제9권2호
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• pp.46-54
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• 2021

최근, 차량의 자율주행에 대한 기술이 개발되면서 안정성은 매우 흥미로운 요소로 관심이 증대되고 있다. 그리고 자율주행에 대하여 1980년대 중반부터 전세계의 많은 대학, 연구 센터, 자동차 회사, 그리고 다른 산업의 회사들에 의해 연구 및 개발되고 있다. 본 연구에서는 자율주행 차량의 안전성을 위한 도로의 위협적인 장애물을 자동 추출하는 방안에 대한 기초 연구를 제안한다. 자동차 도로 위에는 다양한 장애물들이 존재하지만, 본 연구에서는 위협적인 장애물은 도로의 중앙에 위치하며 비교적 큰 개체로 정의한다. 먼저, 입력 영상에 대하여 해상도를 달리하여 분할하고 분할된 영역들은 내부 영역과 외부 영역으로 분류한다. 외부 영역은 영상의 경계에 인접하고 내부 영역은 그렇지 않다. 또한, 저해상도 영상에 인접한 영역이 동일한 영역에 포함되면 각 영역은 인접 영역과 병합된다. 그리고 주요한 객체 영역과 주요한 배경 영역은 각각 내부 영역과 외부 영역에서 선택된다. 따라서, 주요한 객체 영역은 면적과 크기 정보를 활용하여 장애물을 대표하는 영역으로 추출된다. 실험을 통하여 제안된 방법이 자동차 자율주행 안전성을 높여 사고와 사상자를 줄일 수 있는 기초연구에 기여할 수 있을 것으로 기대한다.

• 센서학회지
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• 제14권2호
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• pp.101-108
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• 2005

The research on the avoidance of the large-obstacles such as a wall, a large box, etc. using ultrasonic sensors has been generally progressed up to now. But the mobile robot could meet a small-obstacle such as a small plastic bottle, a small sphere, and so on in its designated path, and could be disturbed by them in the locomotion of the mobile robot. So, it is necessary to research on the avoidance of a small-obstacle. In this paper, a robot's small-obstacle perceiving system was designed and fabricated by arranging four ultrasonic sensors on the plastic plate to avoid small-obstacles. The system was installed on the upper part of the mobile robot with the slope angles between $40.7^{\circ}$ and $23.3^{\circ}$ to a horizontal line and the dynamic characteristic test of the robot was performed. As the result, it was confirmed that the mobile robot with the system could avoid small-obstacles in indoor environment safely.