• Title/Summary/Keyword: Collision detect

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Spatial Resolution Improvement Using Over Sampling and High Agile Maneuver in Remote Sensing Satellite

  • Kim, Hee-Seob;Kim, Gyu-Sun;Chung, Dae-Won;Kim, Eung-Hyun
    • International Journal of Aeronautical and Space Sciences
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    • v.8 no.2
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    • pp.37-43
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    • 2007
  • Coordination of multiple UAVs is an essential technology for various applications in robotics, automation, and artificial intelligence. In general, it includes 1) waypoints assignment and 2) trajectory generation. In this paper, we propose a new method for this problem. First, we modify the concept of the standard visibility graph to greatly improve the optimality of the generated trajectories and reduce the computational complexity. Second, we propose an efficient stochastic approach using simulated annealing that assigns waypoints to each UAV from the constructed visibility graph. Third, we describe a method to detect collision between two UAVs. FinallY, we suggest an efficient method of controlling the velocity of UAVs using A* algorithm in order to avoid inter-UAV collision. We present simulation results from various environments that verify the effectiveness of our approach.

Waypoints Assignment and Trajectory Generation for Multi-UAV Systems

  • Lee, Jin-Wook;Kim, H.-Jin
    • International Journal of Aeronautical and Space Sciences
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    • v.8 no.2
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    • pp.107-120
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    • 2007
  • Coordination of multiple UAVs is an essential technology for various applications in robotics, automation, and artificial intelligence. In general, it includes 1) waypoints assignment and 2) trajectory generation. In this paper, we propose a new method for this problem. First, we modify the concept of the standard visibility graph to greatly improve the optimality of the generated trajectories and reduce the computational complexity. Second, we propose an efficient stochastic approach using simulated annealing that assigns waypoints to each UAV from the constructed visibility graph. Third, we describe a method to detect collision between two UAVs. FinallY, we suggest an efficient method of controlling the velocity of UAVs using A* algorithm in order to avoid inter-UAV collision. We present simulation results from various environments that verify the effectiveness of our approach.

Determination of Tool Orientation in 5-axis Milling Using Potential Energy Method (포텐셜 에너지를 이용한 5축 NC 밀링의 공구방향 결정)

  • 조인행;이건우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.199-204
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    • 1994
  • A method for determining the collision-free tool orientation for 5-axis milling is presented. In 5-axis milling, the proper tool orientation as well as the optimal CC-data has to be selected to machine the workpiece efficiently and accurately and accurately. Essentially, the tool orientation should be determined to avoid collisions between the tool and workpiece and to enable efficient machining. In this work, the tool orientation is determined at every CC-point which is assumed to be given. The procedure uses the potential energy method that assumes the tool and the part surfaces are charged with static electricity. This approach can detect can deteat both global and local collisions (gouging) irrespective of the tool shape. Further, in order to increase the machining efficiency, the material removal rate is maximized simultaneously.

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A Study of the Obstacle Detection System Using Virtual Bumper(1) (Virtual Bumper를 이용한 장애물감지에 관한 연구(I))

  • 최성락;김선호;박경택;유득신
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 1999.10a
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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.

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The Development of Collision Avoidance Algorithm for Unmanned Vehicle Using Ultrasonic Range Sensors

  • Mohammad, Rahmati;Kim, Jung-Ha
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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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 ...

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Identification of Wi-Fi and Bluetooth Signals at the Same Frequency using Software Defined Radio

  • Do, Van An;Rana, Biswarup;Hong, Ic-Pyo
    • Journal of IKEEE
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    • v.25 no.2
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    • pp.252-260
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    • 2021
  • In this paper, a method of using Software Defined Radio (SDR) is proposed for improving the accuracy of identifying two kinds of signals as Wireless Fidelity (Wi-Fi) signal and Bluetooth signal at the same frequency band of 2.4 GHz based on the time-domain signal characteristic. An SDR device was set up for collecting transmitting signals from Wi-Fi access points (Wi-Fi) and mobile phones (Bluetooth). Different characteristics between Wi-Fi and Bluetooth signals were extracted from the measured result. The SDR device is programmed with a Wi-Fi and Bluetooth detection algorithm and a collision detection algorithm to detect and verify the Wi-Fi and Bluetooth signals based on collected IQ data. These methods are necessary for some applications like wireless communication optimization, Wi-Fi fingerprint localization, which helps to avoid interference and collision between two kinds of signals.

Interactive Colision Detection for Deformable Models using Streaming AABBs

  • Zhang, Xinyu;Kim, Young-J.
    • 한국HCI학회:학술대회논문집
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    • 2007.02c
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    • pp.306-317
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    • 2007
  • We present an interactive and accurate collision detection algorithm for deformable, polygonal objects based on the streaming computational model. Our algorithm can detect all possible pairwise primitive-level intersections between two severely deforming models at highly interactive rates. In our streaming computational model, we consider a set of axis aligned bounding boxes (AABBs) that bound each of the given deformable objects as an input stream and perform massively-parallel pairwise, overlapping tests onto the incoming streams. As a result, we are able to prevent performance stalls in the streaming pipeline that can be caused by expensive indexing mechanism required by bounding volume hierarchy-based streaming algorithms. At run-time, as the underlying models deform over time, we employ a novel, streaming algorithm to update the geometric changes in the AABB streams. Moreover, in order to get only the computed result (i.e., collision results between AABBs) without reading back the entire output streams, we propose a streaming en/decoding strategy that can be performed in a hierarchical fashion. After determining overlapped AABBs, we perform a primitive-level (e.g., triangle) intersection checking on a serial computational model such as CPUs. We implemented the entire pipeline of our algorithm using off-the-shelf graphics processors (GPUs), such as nVIDIA GeForce 7800 GTX, for streaming computations, and Intel Dual Core 3.4G processors for serial computations. We benchmarked our algorithm with different models of varying complexities, ranging from 15K up to 50K triangles, under various deformation motions, and the timings were obtained as 30~100 FPS depending on the complexity of models and their relative configurations. Finally, we made comparisons with a well-known GPU-based collision detection algorithm, CULLIDE [4] and observed about three times performance improvement over the earlier approach. We also made comparisons with a SW-based AABB culling algorithm [2] and observed about two times improvement.

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Implementation of two wire RS232C Serial Communication Interface using CSMA protocol (충돌검지 다중접속 프로토콜에 의한 2선식 RS232C 직렬통신 인터페이스 구현)

  • 한경호;최천원
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.3
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    • pp.11-17
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    • 2003
  • In this paper, we implemented 2-wire (data gnd) RS232C serial communication interface by applying the Collision Sensing Multiple Access(CSMA) Protocol. The transmitting and receiving wires of RS232C pert are connected together by the interface circuit forming data wire without hardware modification On two-wired common channel connection simultaneous transmission Don mere than two hosts causes data collision. The collision is detected by loop-back test of transmission data comparing with the fed back data to detect the data distortion. Various models are adopted to reduce the probability of retransmitted data collision and experiments show the performance of each cases. Due to allowing multiple hosts to be accessed through the common communication channel with minimum circuit addition the result of this paper can be easily applied for conventional RS232C instruments and machines to connect to the single data communication line.

Vehicle-following system using color-vision

  • 정준형;한민홍
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1994.04a
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    • pp.536-542
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    • 1994
  • This paper introduces a vehicle-following-system in which a moving vehicle recognizes the front vehicle's tail-light color and luminance, while maintaining a certain distance and avoiding collision. Using color images rather than using gray-scale images makes it easier to detect the objective color and eliminates the need of a thresholding. The Methods used are RGB to HSV conversion and global region growing method. This paper contributes to the basic study of Color-Vision, and can be extended to color inspection systems.

Development of the autnomous road vehicle (무인 자동차 개발 연구)

  • 최진욱;한민홍
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.88-93
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    • 1993
  • This paper introduces an ARV(Autonomous Road Vehicle) system which can run on orads without help of a driver by detecting road boundaries through computer vision. This vehicle can also detect obstacles in front through sonar sensors and infrared sensors. This system largely consists of a handle steering module and a braking module. From road boundaries, the steering module determines handle turn angle. The braking module stops or decelerates to avoid collision depending on the relative speeds and distance to the obstacles detected by different sensors. This ARV system has been implemented in a small jeep and can run 30-40 km/h city traffic. In this paper, we illustrate the structure of the ARV systems and its operation principle.

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