• Title/Summary/Keyword: Collision configuration

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Collision-Free Path Planning for a Redundant Manipulator Based on PRM and Potential Field Methods (PRM과 포텐셜 필드 기법에 기반한 다자유도 머니퓰레이터의 충돌회피 경로계획)

  • Park, Jung-Jun;Kim, Hwi-Su;Song, Jae-Bok
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.4
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    • pp.362-367
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    • 2011
  • The collision-free path of a manipulator should be regenerated in the real time to achieve collision safety when obstacles or humans come into the workspace of the manipulator. A probabilistic roadmap (PRM) method, one of the popular path planning schemes for a manipulator, can find a collision-free path by connecting the start and goal poses through the roadmap constructed by drawing random nodes in the free configuration space. The path planning method based on the configuration space shows robust performance for static environments which can be converted into the off-line processing. However, since this method spends considerable time on converting dynamic obstacles into the configuration space, it is not appropriate for real-time generation of a collision-free path. On the other hand, the method based on the workspace can provide fast response even for dynamic environments because it does not need the conversion into the configuration space. In this paper, we propose an efficient real-time path planning by combining the PRM and the potential field methods to cope with static and dynamic environments. The PRM can generate a collision-free path and the potential field method can determine the configuration of the manipulator. A series of experiments show that the proposed path planning method can provide robust performance for various obstacles.

Self-Collision Avoidance using Configuration Space Approach for Redundant Manipulators (Configuration Space 접근법을 이용한 여유 자유도 로봇의 자기 충돌 회피)

  • 문재성;정완균;염영일
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.321-324
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    • 2003
  • There are two steps to solve the self-collision avoidance problems for redundant manipulators. First, all links are regarded as cylinders. and then the collisions should be checked among all pairs of the links. Between two cylinders. we can get the collision information derived from the concept or configuration space obstacle in real time. Therefore. it is possible to detect the links where collisions are likely in real time by setting the risk radius which is larger than actual radius. Second. the configuration control points (CCP) should be placed at the ends of the detected links. A cost function is the sum of the distances between the CCPs. To maximize the cost function means the links go far away each other without self-collisions.

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Collision Configurations Reconstruction Using Deformation Shape and Deformation Severity of Car Body (차체의 변형상과 변형정도에 의한 자동차 충돌상황의 재구성)

  • 장인식;채덕병
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.1
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    • pp.171-180
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    • 2001
  • Collision accident reconstruction algorithm are developed based on the deformation shape and severity of a car body. At first, the body stiffness equation representing the force-deformation relationship is derived using finite element analysis for head on collision of two cars. The database of deformation shapes and energies is constructed for five different collision configurations; each configuration contains three velocity conditions. Deformation shapes are obtained using a curve fitting method and result in cubic polynomials. Deformation energies are calculated using a stiffness equation and deformation data. Three algorithms are developed to reconstruct collision configuration compared with constructed database. The developed algorithms show reasonably good performance to find collisions conditions for some test problems.

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OPTIMAL FORMATION TRAJECTORY-PLANNING USING PARAMETER OPTIMIZATION TECHNIQUE

  • Lim, Hyung-Chul;Bang, Hyo-Choong;Park, Kwan-Dong;Lee, Woo-Kyoung
    • Journal of Astronomy and Space Sciences
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    • v.21 no.3
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    • pp.209-220
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    • 2004
  • Some methods have been presented to get optimal formation trajectories in the step of configuration or reconfiguration, which subject to constraints of collision avoidance and final configuration. In this study, a method for optimal formation trajectory-planning is introduced in view of fuel/time minimization using parameter optimization technique which has not been applied to optimal trajectory-planning for satellite formation flying. New constraints of nonlinear equality are derived for final configuration and constraints of nonlinear inequality are used for collision avoidance. The final configuration constraints are that three or more satellites should be placed in an equilateral polygon of the circular horizontal plane orbit. Several examples are given to get optimal trajectories based on the parameter optimization problem which subjects to constraints of collision avoidance and final configuration. They show that the introduced method for trajectory-planning is well suited to trajectory design problems of formation flying missions.

Collision-free path planning for two cooperating robot manipulators using reduced dimensional configuration space (축소 차원 형상 공간을 이용한 협조작업 두 팔 로봇의 충돌 회피 경로 계획)

  • 최승문;이석원;이범희
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.904-907
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    • 1996
  • In this paper, we propose an efficient collision-free path planning method of two cooperating robot manipulators grasping a common object rigidly. For given two robots and an object, the procedure is described which constructs the reduced dimensional configuration space by the kinematic analysis of two cooperating robot manipulators. A path planning algorithm without explicit representation of configuration obstacles is also described. The primary steps of the algorithm is as follows. First, we compute a graph which represents the skeleton of the free configuration space. Second, a connection between an initial and a goal configuration to the graph is searched to find a collision-free path.

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Collision-Free Path Planning of Articulated Robot using Configuration Space (형상 공간을 이용한 다관절 로보트의 충돌 회피 경로 계획)

  • Kim, J.H.;Choi, J.S.;Kang, H.Y.;Kim, Dong-Won;Yang, S.M.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.6
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    • pp.57-65
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    • 1994
  • A collision-free path planning algorithm between an articulated robot and polyhedral obstacles using configuration space is presented. In configuration space, a robot is treated as a point and obstacles are treated as grown forbidden regions. Hence path planning problem is transformed into moving a point from start position to goal position without entering forbidden regions. For mapping to 3D joint space, slice projection method is used for first revolute joint and inverse kinematics is used for second and third revolute joint considering kinematic characteristics of industrial robot. Also, three projected 2D joint spaces are used in search of collision-free path. A proper example is provided to illustrate the proposed algorithm.

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Collision-Free Motion Planning of a Robot Using Free Arc concept (프리아크 개념을 이용한 로봇의 충돌회피 동작 계획)

  • Lee, Seok-Won;Nam, Yun-Seok;Lee, Beom-Hee
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.3
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    • pp.317-328
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    • 2000
  • This paper presents an effective approach to collision-free motion planning of a robot in the work-space including time-varying obstacles. The free arc is defined as a set composed of the configuration points of the robot satisfying collision-free motion constraint at each sampling time. We represent this free arc with respect to the new coordinate frame centered at the goal configuration and there for the collision-free path satisfying motion constraint is obtained by connecting the configuration points of the free arc at each sampling mined from the sequence of free arcs the optimality is determined by the performance index. Therefore the complicated collision-free motion planning problem of a robot is transformed to a simplified SUB_Optimal Collision Avoidance Problem(SOCAP). We analyze the completeness of the proposed approach and show that it is partly guaranteed using the backward motion. Computational complexity of our approach is analyzed theoretically and practical computation time is compared with that of the other method. Simulation results for two cally and practical computation time is compared with that of the other method. Simulation results for two SCARA robot manipulators are presented to verify the efficacy of the proposed method.

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Trajectory Planning of Satellite Formation Flying using Nonlinear Programming and Collocation

  • Lim, Hyung-Chu;Bang, Hyo-Choong
    • Journal of Astronomy and Space Sciences
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    • v.25 no.4
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    • pp.361-374
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    • 2008
  • Recently, satellite formation flying has been a topic of significant research interest in aerospace society because it provides potential benefits compared to a large spacecraft. Some techniques have been proposed to design optimal formation trajectories minimizing fuel consumption in the process of formation configuration or reconfiguration. In this study, a method is introduced to build fuel-optimal trajectories minimizing a cost function that combines the total fuel consumption of all satellites and assignment of fuel consumption rate for each satellite. This approach is based on collocation and nonlinear programming to solve constraints for collision avoidance and the final configuration. New constraints of nonlinear equality or inequality are derived for final configuration, and nonlinear inequality constraints are established for collision avoidance. The final configuration constraints are that three or more satellites should form a projected circular orbit and make an equilateral polygon in the horizontal plane. Example scenarios, including these constraints and the cost function, are simulated by the method to generate optimal trajectories for the formation configuration and reconfiguration of multiple satellites.

Boundary-RRT* Algorithm for Drone Collision Avoidance and Interleaved Path Re-planning

  • Park, Je-Kwan;Chung, Tai-Myoung
    • Journal of Information Processing Systems
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    • v.16 no.6
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    • pp.1324-1342
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    • 2020
  • Various modified algorithms of rapidly-exploring random tree (RRT) have been previously proposed. However, compared to the RRT algorithm for collision avoidance with global and static obstacles, it is not easy to find a collision avoidance and local path re-planning algorithm for dynamic obstacles based on the RRT algorithm. In this study, we propose boundary-RRT*, a novel-algorithm that can be applied to aerial vehicles for collision avoidance and path re-planning in a three-dimensional environment. The algorithm not only bounds the configuration space, but it also includes an implicit bias for the bounded configuration space. Therefore, it can create a path with a natural curvature without defining a bias function. Furthermore, the exploring space is reduced to a half-torus by combining it with simple right-of-way rules. When defining the distance as a cost, the proposed algorithm through numerical analysis shows that the standard deviation (σ) approaches 0 as the number of samples per unit time increases and the length of epsilon ε (maximum length of an edge in the tree) decreases. This means that a stable waypoint list can be generated using the proposed algorithm. Therefore, by increasing real-time performance through simple calculation and the boundary of the configuration space, the algorithm proved to be suitable for collision avoidance of aerial vehicles and replanning of local paths.

Collision Free Path Planing of Articulated Manipulator for Remote Maintenance Using Sequential Search Method (원격 유지보수용 다관절 조작기의 순차 탐색에 의한 장애물 회피 경로계획)

  • 이종열;송태길;김성현;박병석;윤지섭
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.519-522
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    • 1997
  • In this study, the collision free path planning method of the articulated manipulator using sequential search is proposed. This method is to find the joint path of the manipulator with many degrees of freedom from the distal joint to the proximal one. To do this, the initial work space of the gantry manipulator, which is a remote maintenance equipment of the radioactive environment, is defined from the condition that the distal joint configuration is determined by the posture of maintenance. Then, 2-dimensional configuration space with the obstacle area is represented and the collision free path of manipulator is searched in the configuration space. And, this method is verified using the graphic simulation in virtual workcell for the spent fuel disassembling processes. The result of this study can be effectively used in implementing the maintenance processes for the hot cell equipment and enhance the reliability of the spent fuel management.

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