• Title/Summary/Keyword: trajectory planning

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Optimal Task Planning for Collision-Avoidance of Dual-Arm Robot Using Neural Network (신경회로망을 이용한 이중암 로봇의 충돌회피를 위한 최적작업계획)

  • 최우형
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.176-181
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    • 2000
  • Collision free task planning for dual-arm robot which perform many subtasks in a common work space can be achieved in two steps : path planning and trajectory planning. path planning finds the order of tasks for each robot to minimize path lengths as well as to avoid collision with static obstacles. A trajectory planning strategy is to let each robot move along its path as fast as possible and delay one robot at its initial position or reduce speed at the middle of its path to avoid collision with the other robot.

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Trajectory Optimization for Autonomous Berthing of a Twin-Propeller Twin-Rudder Ship

  • Changyu Lee;Jinwhan Kim
    • Journal of Ocean Engineering and Technology
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    • v.37 no.3
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    • pp.122-128
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    • 2023
  • Autonomous berthing is a crucial technology for autonomous ships, requiring optimal trajectory planning to prevent collisions and minimize time and control efforts. This paper presents a two-phase, two-point boundary value problem (TPBVP) strategy for creating an optimal berthing trajectory for a twin-propeller, twin-rudder ship with autonomous berthing capabilities. The process is divided into two phases: the approach and the terminal. Tunnel thruster use is limited during the approach but fully employed during the terminal phase. This strategy permits concurrent optimization of the total trajectory duration, individual phase trajectories, and phase transition time. The efficacy of the proposed method is validated through two simulations. The first explores a scenario with phase transition, and the second generates a trajectory relying solely on the approach phase. The results affirm our algorithm's effectiveness in deciding transition necessity, identifying optimal transition timing, and optimizing the trajectory accordingly. The proposed two-phase TPBVP approach holds significant implications for advancements in autonomous ship navigation, enhancing safety and efficiency in berthing operations.

Maximum Velocity Trajectory Planning for Mobile Robots Considering Wheel Velocity Limit (이동로봇의 바퀴 속도 제한을 고려한 최대 속도궤적 생성 방법)

  • Yang, Gil Jin;Choi, Byoung Wook
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.5
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    • pp.471-476
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    • 2015
  • This paper presents a maximum velocity trajectory planning algorithm for differential mobile robots with wheel velocity constraint to cope with physical limits in the joint space for two-wheeled mobile robots (TMR). In previous research, the convolution operator was able to generate a central velocity that deals with the physical constraints of a mobile robot while considering the heading angles along a smooth curve in terms of time-dependent parameter. However, the velocity could not track the predefined path. An algorithm is proposed to compensate an error that occurs between the actual and driven distance by the velocity of the center of a TMR within a sampling time. The velocity commands in Cartesian space are also converted to actuator commands to drive two wheels. In the case that the actuator commands exceed the maximum velocity the trajectory is redeveloped with the compensated center velocity. The new center velocity is obtained according to the curvature of the path to provide a maximum allowable velocity meaning a time-optimal trajectory. The effectiveness of the algorithm is shown through numerical examples.

Low thrust inclined circular trajectories for airplanes

  • Labonte, Gilles
    • Advances in aircraft and spacecraft science
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    • v.4 no.3
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    • pp.237-267
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    • 2017
  • Automatic trajectory re-planning is an integral part of unmanned aerial vehicle mission planning. In order to be able to perform this task, it is necessary to dispose of formulas or tables to assess the flyability of various typical flight segments. Notwithstanding their importance, there exist such data only for some particularly simple segments such as rectilinear and circular sub-trajectories. This article presents an analysis of a new, very efficient, way for an airplane to fly on an inclined circular trajectory. When it flies this way, the only thrust required is that which cancels the drag. It is shown that, then, much more inclined trajectories are possible than when they fly at constant speed. The corresponding equations of motion are solved exactly for the position, the speed, the load factor, the bank angle, the lift coefficient and the thrust and power required for the motion. The results obtained apply to both types of airplanes: those with internal combustion engines and propellers, and those with jet engines. Conditions on the trajectory parameters are derived, which guarantee its flyability according to the dynamical properties of a given airplane. An analytical procedure is described that ensures that all these conditions are satisfied, and which can serve for producing tables from which the trajectory flyability can be read. Sample calculations are shown for the Cessna 182, a Silver Fox like unmanned aerial vehicle, and an F-16 jet airplane.

Analysis on a Minimum Infinity-norm Solution for Kinematically Redundant Manipulators

  • Insoo Ha;Lee, Jihong
    • Transactions on Control, Automation and Systems Engineering
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    • v.4 no.2
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    • pp.130-139
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    • 2002
  • In this paper, at first, we investigate existing algorithms for finding the minimum infinity-norm solution of consistent linear equations and then propose a new algorithm. The proposed algorithm is intended to includes the advantages of computational efficiency as well as geometric explicitness. As a practical application example, optimum trajectory planning for redundant robot manipulators is considered. Also, an efficient approach avoiding discontinuity in trajectory is proposed by resolving the non-uniqueness problem of minimum infinity-norm solution. To be specific, the proposed method for checking possible discontinuity does not need any other algorithms in checking the possibility of discontinuity while previous work needs specially designed checking courses. To show the usefulness of the proposed techniques, an example calculating minimum infinity-norm solution for comparing the computational efficiency as well as the trajectory planning for a redundant robot manipulator are included.

A Near Minimum-Time Trajectory Planning for Two Robots Using Dynamic Programming Technique (다이나믹 프로그래밍에 의한 두 대의 로보트를 위한 최소시간 경로계획)

  • 이지홍;오영석
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.29B no.11
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    • pp.36-45
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    • 1992
  • A numerical trajectory planning method for path-constrained trajectory planning is proposed which ensures collision-free and time-optimal motions for two robotic manipulators with limited actuator torques and velocities. For each robot, physical constraints of the robots such as limited torques or limited rotational velocities of the actuators are converted to the constraints on velocity and acceleration along the path, which is described by a scalar variable denoting the traveled distance from starting point. Collision region is determined on the coordination space according to the kinematic structures and the geometry of the paths of the robots. An Extended Coordination Space is then constructed` an element of the space determines the postures and the velocities of the robots, and all the constraints described before are transformed to some constraints on the behaviour of the coordination-velocity curves in the space. A dynamic programming technique is them provided with on the discretized Extended Coordination Space to derive a collision-free and time-optimal trajectory pair. Numerical example is included.

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A Smoothed Gait Trajectory Planning of a 9-link Biped Robot (9 링크 이족로봇의 부드러운 걸음새 경로 계획)

  • Kim, Chul-Ha;Yoo, Sung-Jin;Choi, Yoon-Ho;Park, Jin-Bae;Seok, Kwak-Ki
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.424-426
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    • 2005
  • We propose an analytic trajectory planning method using a wavelet neural network (WNN) for a natural and stable locomotion of the 9-link biped robot. We design a appropriate locomotion, which have a kick-action, by means of a ballastic walking model condition. In this paper, a WNN is used to interpolate the trajectory planed by the analytic method. Finally, we show the proposed trajectories through the computer simulation.

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A Minimum time trajectory planning for robotic manipulators with input torque constraint (입력 토오크 constraint를 가진 로보트 매니플레이터에 대한 최소 시간 궤적 계획)

  • Hong, In-Keun;Hong, Suk-Kyo
    • Proceedings of the KIEE Conference
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    • 1989.11a
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    • pp.445-449
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    • 1989
  • Achievement of a straight line motion in the Cartesian space has a matter of great importance. Minimization of task execution time with linear interpolation in the joint space, accomplishing of a approximation of straight line motion in the Cartesian coordinate is considered as the prespecified task. Such determination yields minimum time joint-trajectory subject to input torque constraints. The applications of these results for joint-trajectory planning of a two-link manipulator with revolute joints are demonstrated by computer simulations.

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