• Title, Summary, Keyword: occluded dynamic obstacle

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Safe Navigation of a Mobile Robot Considering the Occluded Obstacles (가려진 동적 장애물을 고려한 이동로봇의 안전한 주행기술개발)

  • Kim, Seok-Gyu;Chung, Woo-Jin
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.2
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    • pp.141-147
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    • 2008
  • In this paper, we present one approach to achieve safe navigation in indoor dynamic environment. So far, there have been various useful collision avoidance algorithms and path planning schemes. However, those algorithms have a fundamental limitation that the robot can avoid only "visible" obstacles. In real environment, it is not possible to detect all the dynamic obstacles around the robot. There exist a lot of "occluded" regions due to the limitation of field of view. In order to avoid possible collisions, it is desirable to consider visibility information. Then, a robot can reduce the speed or modify a path. This paper proposes a safe navigation scheme to reduce the risk of collision due to unexpected dynamic obstacles. The robot's motion is controlled according to a hybrid control scheme. The possibility of collision is dually reflected to a path planning and a speed control. The proposed scheme clearly indicates the structural procedure on how to model and to exploit the risk of navigation. The proposed scheme is experimentally tested in a real office building. The presented result shows that the robot moves along the safe path to obtain sufficient field of view, while appropriate speed control is carried out.

Human Assisted Fitting and Matching Primitive Objects to Sparse Point Clouds for Rapid Workspace Modeling in Construction Automation (-건설현장에서의 시공 자동화를 위한 Laser Sensor기반의 Workspace Modeling 방법에 관한 연구-)

  • KWON SOON-WOOK
    • Korean Journal of Construction Engineering and Management
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    • v.5 no.5
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    • pp.151-162
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    • 2004
  • Current methods for construction site modeling employ large, expensive laser range scanners that produce dense range point clouds of a scene from different perspectives. Days of skilled interpretation and of automatic segmentation may be required to convert the clouds to a finished CAD model. The dynamic nature of the construction environment requires that a real-time local area modeling system be capable of handling a rapidly changing and uncertain work environment. However, in practice, large, simple, and reasonably accurate embodying volumes are adequate feedback to an operator who, for instance, is attempting to place materials in the midst of obstacles with an occluded view. For real-time obstacle avoidance and automated equipment control functions, such volumes also facilitate computational tractability. In this research, a human operator's ability to quickly evaluate and associate objects in a scene is exploited. The operator directs a laser range finder mounted on a pan and tilt unit to collect range points on objects throughout the workspace. These groups of points form sparse range point clouds. These sparse clouds are then used to create geometric primitives for visualization and modeling purposes. Experimental results indicate that these models can be created rapidly and with sufficient accuracy for automated obstacle avoidance and equipment control functions.