• 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.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.951-957
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• 1988

A collision-free trajectory planning algorithm is proposed to optimally coordinate two robots working in a common 3-D workspace. Each link of the two robots is modeled as a line segment and by their motion priority, one of the two robots is chosen as the master and the other the slave. And the one-step-ahead minimum distance between the two robots is computed by moving the master to the next location on its specified trajectory. Then the nominal trajectory of the slave is modified such that the distance between the next locations of the master and the slave must be larger than a prespecified allowable minimum distance. Here the weighted sum of the trajectory error and the joint motions of the slave is minimized by using the linear programming technique under the constraints that joint angle and velocity limits are not violated. To show the validity of the proposed algorithm, a numerical example is illustrated by employing a two dof's and a three dof's planar robots.

• Journal of Astronomy and Space Sciences
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• v.30 no.1
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• pp.11-15
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• 2013

A collision-free formation reconfiguration trajectory subject to the linearized Hill's dynamics of relative motion is analytically developed by extending an algorithm for gravity-free space. Based on the initial solution without collision avoidance constraints, the final solution to minimize the designated performance index and avoid collision is found, based on a gradient method. Simple simulations confirm that satellites reconfigure their positions along the safe trajectories, while trying to spend minimum energies. The algorithm is applicable to wide range of formation flying under the Hill's dynamics.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.8
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• pp.563-569
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• 1988

This research presents several velocity modification methods for collision avoidance of two manipulators in a common workspace. Due to the distinct nature of collision avoidance between the two manipulators, a new classification of collision situations is presented and utilized in planning a collision-free path. Concepts of a collision map and velocity modification are applied for realizing collision-free motion planning. An example is shown for velocity modification of a trajectory, which shows the significance of the proposed approaches in collision-free motion planneng of two moving robots.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.357-368
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• 1991

Collision-free trajectory planning for two robots is considered. The two robot system handled in the paper is given specified geometric paths for two robots, and the task is repeating. Then, the robot dynamics is transformed as a function of the traveled lengths along the paths, and the bounds on acceleration and velocity are described in the phase plane be taking the constraints on torques and joint velocities into consideration. Collision avoidance and time optimality are considered simultaneously in the coordination space and the phase plane, respectively. The proof for the optimality of the proposed algorithm is given, and a simulation result is included to show the usefulness of the proposed method.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.8-18
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• 2005

Pedestrians involved in traffic accidents manifest unique trajectory characteristics depending on the collision speed, vehicle configuration, and pedestrian postures. However, the existing analytical models for pedestrian movements do not fully include the rotational characteristics of the pedestrians because they assume a two dimensional parabolic trajectory. This faulty assumption in the development of these models limits their applicability and reliability This study investigated the pedestrians movement at collision by computer simulation. The simulations are carried out by using HADYMO, which is a special simulation software system for dynamic movement analysis. Vehicles and pedestrians are modeled and verified via real crash worthiness experiments. Simulations are performed for various collision speeds, vehicle configuration, and pedestrian postures. Since the simulation uses multi-body dynamics, It can express irregular phenomena of the bodies quite well. The results can be exploited for vehicle design and traffic accident reconstruction.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.915-920
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• 1987

When a task requires two robot arms to move in a cooperative manner sharing a common workspace, potential collision exists between the two robot arm . In this paper, a novel approach for collision-free trajectory planning along paths of two SCARA-type robot arms is presented. Specifically, in order to describe potential collision between the links of two moving robot arms along the designated paths, an explicit form of "Virtual Obstacle" is adopted, according to which links of one robot arm are made to grow while the other robot arm is forced to shrink as a point on the path. Then, a notion of "Coordination Chart" is introduced to visualize the collision-free relationship of two trajectories.of two trajectories.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.122-127
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• 1996

The achievement of the optimal condition for the task of an industrial articulated robot used in many fields is an important problem to improve productivity. In this paper, a minimum-time trajectory for an articulated robot along the specified path is studied and simulated with a proper example. A general dynamic model of manipulator is represented as a function of path distance. Using this model, the velocity is produced as fast as possible at each point along the path. This minimum-time trajectory planning module together with the existing collision-free path planning modules is utilized to design the optimal path planning of robot in cases where obstacles present.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.759-762
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• 1991

In this paper an algorithm is presented which serves for collision avoidance between robots with working space. The method is based on the concept of a hierarchical coordinator and permits an on-line application. Computing possible collision points a collision_free trajectory for the robot with no right_of_way precedence is generated. The computations are based on the states of the robots concerned including their practicable accelerations and velocities.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.184-189
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• 2002

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.