• Title/Summary/Keyword: Path Point

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Real-time Obstacle Detection and Avoidance Path Generation Algorithm for UAV (무인항공기용 실시간 장애물 탐지 및 회피 경로 생성 알고리즘)

  • Ko, Ha-Yoon;Baek, Joong-Hwan;Choi, Hyung-Sik
    • Journal of Advanced Navigation Technology
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    • v.22 no.6
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    • pp.623-629
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    • 2018
  • In this paper, we propose a real-time obstacle detection and avoidance path generation algorithm for UAV. 2-D Lidar is used to detect obstacles, and the detected obstacle data is used to generate real-time histogram for local avoidance path and a 2-D SLAM map used for global avoidance path generation to the target point. The VFH algorithm for local avoidance path generation generates a real-time histogram of how much the obstacles are distributed in the vector direction and distance, and this histogram is used to generate the local avoidance path when detecting near fixed or dynamic obstacles. We propose an algorithm, called modified $RRT^*-Smart$, to overcome existing limitations. That generates global avoidance path to the target point by creating lower costs because nodes are checked whether or not straight path to a target point, and given arbitrary lengths and directionality to the target points when nodes are created. In this paper, we prove the efficient avoidance maneuvering through various simulation experiment environment by creating efficient avoidance paths.

Path Planning for Search and Surveillance of Multiple Unmanned Aerial Vehicles (다중 무인 항공기 이용 감시 및 탐색 경로 계획 생성)

  • Sanha Lee;Wonmo Chung;Myunggun Kim;Sang-Pill Lee;Choong-Hee Lee;Shingu Kim;Hungsun Son
    • The Journal of Korea Robotics Society
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    • v.18 no.1
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    • pp.1-9
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    • 2023
  • This paper presents an optimal path planning strategy for aerial searching and surveying of a user-designated area using multiple Unmanned Aerial Vehicles (UAVs). The method is designed to deal with a single unseparated polygonal area, regardless of polygonal convexity. By defining the search area into a set of grids, the algorithm enables UAVs to completely search without leaving unsearched space. The presented strategy consists of two main algorithmic steps: cellular decomposition and path planning stages. The cellular decomposition method divides the area to designate a conflict-free subsearch-space to an individual UAV, while accounting the assigned flight velocity, take-off and landing positions. Then, the path planning strategy forms paths based on every point located in end of each grid row. The first waypoint is chosen as the closest point from the vehicle-starting position, and it recursively updates the nearest endpoint set to generate the shortest path. The path planning policy produces four path candidates by alternating the starting point (left or right edge), and the travel direction (vertical or horizontal). The optimal-selection policy is enforced to maximize the search efficiency, which is time dependent; the policy imposes the total path-length and turning number criteria per candidate. The results demonstrate that the proposed cellular decomposition method improves the search-time efficiency. In addition, the candidate selection enhances the algorithmic efficacy toward further mission time-duration reduction. The method shows robustness against both convex and non-convex shaped search area.

Tool Path Analysis and Motion Control of 3D Engraving Machine

  • Smerpitak, Krit;Pongswatd, Sawai;Ukakimapurn, Prapart
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.1245-1248
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    • 2004
  • This paper presents a new technique to analyze data on the coordinate x, y, z and apply these data to design the motion control to improve the efficiency of the engraving machine so that it can engrave accordingly in 3 dimensions. First, the tool path on the x-y plane is analyzed to be synchronized with the z-axis. The digital data is then sent to the motion control to guide the movement of the engrave point on the x-y plane. Tool path moves along the x-axis with zero degree and different values of the y-axis according to the coordinate of the digital data and the analysis along z-axis to determine the depth for engraving. The depth can be specified from the gray level with the 256 levels of resolution. The data obtained includes the distances on x-axis, y-axis, and z-axis, the acceleration of the engrave point's movement, and the speed of the engrave point's movement. These data is then transfered to the motion control to guide the movement of the engrave point along the z-axis associated with the x-y plane. The results indicate that engraving using this technique is fast and continuous. The specimen obtained looks perfect in 3D view.

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Geometric Path Tracking for a Fish Robot (물고기 로봇의 기하학적 경로 추종)

  • Park, Jin-Hyun;Choi, Young-Kiu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.4
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    • pp.906-912
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    • 2014
  • The study of fish robot is a main subject that are related with the propulsive force comparison using a varying amplitude and frequency for body and tail motion trajectory, and the quick turn using a proper trajectory function. In this study, when a fish robot thrusts forward, feedback control is difficult to apply for a fish robot, because body and tail joints as a sine wave are rolled. Therefore, we detect the virtual position based on the path of the fish robot, define the angle errors using the detected position and the look-ahead point on the given path, and design a controller to track given path. We have found that the proposed method is useful through the computer simulations.

A Study on Torch Path Generation for Laser Cutting Process (레이저 절단공정에서의 토지경로 생성에 관한 연구)

  • Han, Guk-Chan;Na, Seok-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.6
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    • pp.1827-1835
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    • 1996
  • This paper addresses the problem of a torch path generation for the 2D laser cutting of a stock plate nested with resular or irregular parts. Under the constaint of the relative positions of parts enforced by nesting, the developed torch path algorithm generate feasible cutting path. In this paper, the basic object is a polygon( a many-slide figure) with holes. A part may be represented as a number of line segments connected end-to-end in counterclockwise order, and formed a closed contour as requied for cutting paths. The objective is to tranverse this cutting contours with a minimum path length. This paper proposes a simulated annealing based dtorch path algorithm, that is an improved version of previously suggested TSP models. Since everypiercing point of parts is not fixed in advance, the algorithm solves as relazed optimization problem for the constraint, thich is one of the main features of the proposed algorithm. For aolving the torch path optimization problem, an efficient generation mechanism of neighborhood structure and as annealing shedule were introduced. In this way, a global solution can be obtained in a reasonable time. Seveeral examples are represented to ilustrate the method.

Finding a Second Best Coverage Path (차선거리유지 경로찾기)

  • Na, Hyeon-Suk;Kim, Jung-Hee
    • Journal of KIISE:Computer Systems and Theory
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    • v.35 no.8
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    • pp.385-393
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    • 2008
  • The best coverage problem is finding a path whose worst distance to the sensor-set is the best among all paths. Instead, if the user stays close to its nearest two sensors, then the stability of the wireless connection may be guaranteed. So we consider the problem of finding a second best coverage path; given the sensor set U, a starting point s and a target point t, find a path whose worst distance to the second closest sensor is minimized. This paper presents an O(n logn) -time algorithm to find such a path. We also give experimental evidence showing that the connection to the sensor-set along a second best coverage path is more stable than that along the best coverage path.

A Study on the Obstacle Avoidance Algorithm and Path Planning of Multiple Mobile Robot (다중이동로봇의 장애물 회피 논리 및 경로계획에 관한 연구)

  • Park, Kyung-Jin;Lee, Ki-Sung;Lee, Jong-Soo
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.633-635
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    • 1999
  • In this paper, we propose a new method of path planning for multiple mobile robot in dynamic environment. To search the optimal path, multiple mobile robot is always generating path with static and dynamic obstacles avoidance from start point to goal point. The purpose of this paper is to design an optimal path for the mobile robot.

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A New Algorithm for Complete Coverage Path-Planning of Cleaning Robots (청소 로봇을 위한 경로 계획의 새로운 알고리즘)

  • Jiang, Liu;Son, Young-Ik;Kim, Kab-Il
    • Proceedings of the KIEE Conference
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    • 2005.05a
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    • pp.252-254
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    • 2005
  • Completer coverage path planning requires the robot path to cover every part of the workspace, which is an essential issue in cleaning robots and many other robotic applications such as vacuum robots and painter robots. In this paper, a novel Water Flowing Algorithm (WFA) is proposed for cleaning robots to complete coverage path planning in unknown environment without obstacles. The robot covers the whole workspace just like that water fills up a container. First the robot goes to the lowest point in the workspace just like water flows to the bottom of the container. At last the robot will come to highest point in the workspace just like water overflows from the container and simultaneously the robot has covered the whole workspace. The computer simulation results show that the proposed algorithm enable the robot to plan complete coverage paths.

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Path optimization method for shifting path planning of marking robot (먹매김 로봇 작업경로 설정을 위한 최적경로 탐색방법)

  • Lim, Hyunsu;Kim, Taehoon;Kim, Taehoon;Kim, Chang-Won
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.04a
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    • pp.144-145
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    • 2022
  • Since the marking robot draws lines by point-to-point operation, the robot's shifting path greatly affects the working time and productivity. Therefore, it is required to analyze the movement method based on the robot's motion and plan to minimize the movement time. Therefore, this study proposes a method that can optimize the robot's shifting path to minimize the working time of the marking robot. Through the results of this study, it is expected that the non-working time of the marking robot will be reduced and the efficient operation will be possible.

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A Point-to-Point Shortest Path Search Algorithm for Digraph (방향그래프의 점대점 최단경로 탐색 알고리즘)

  • Lee, Sang-Un
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.7
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    • pp.893-900
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    • 2007
  • This paper suggests an algorithm that improves the disadvantages of the Dijkstra algorithm that is commonly used in GPS navigation system, searching for the shortest path. Dijkstra algorithm, first of all, requires much memory for the performance of the algorithm. It has to carry out number of node minus 1, since it determines the shortest path from all the nodes in the graph, starting from the first node. Therefore, Dijkstra algorithm might not be able to provide the information on every second, searching for the shortest path between the roads of the congested city and the destination. In order to solve these problems, this paper chooses a method of searching a number of nodes at once by means of choosing the shortest path of all the path nodes (select of minimum weight arc in-degree and out-degree), excluding the departure and destination nodes, and of choosing all the arcs that coincide with the shortest path of the path nodes, from all the node outgoing arcs starting from the departure node. On applying the suggested algorithm to 14 various digraphs, we succeeded to search the shortest path. In addition, the result was obtained at the speed of 2 to 3 times faster than that of Dijkstra algorithm, and the memory required was less than that of Dijkstra algorithm.