• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.407-411
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• 1992

A method for optimal route planning is presented with the assumption that the overall defended area is known in terms of threat potential function. This approach employes tangent plane to reduce the dimension of the state space for optimal programming problems with a state equality constraint. One-dimensional search algorithm is used to select the optimal route among the extermal fields which are obtained by integrating three differential equations from the initial values. In addition to being useful for the route planning through threat potential area, the trajectory planning will be suitable for general two-dimensional searching problems.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.283-290
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• 2021

We propose a task and motion planning algorithm for clearing obstacles and wiping surfaces, which is essential for surface disinfection during the pathogen disinfection process. The proposed task and motion planning algorithm determines task parameters such as grasping pose and placement location during the planning process without using pre-specified or discretized values. Furthermore, to quickly inspect many unit motions, we propose a motion feasibility prediction algorithm consisting of collision checking and an SVM model for inverse mechanics and self-collision prediction. Planning time analysis shows that the feasibility prediction algorithm can significantly increase the planning speed and success rates in situations with multiple obstacles. Finally, we implemented a hierarchical control scheme to enable wiping motion while following a planner-generated joint trajectory. We verified our planning and control framework by conducted an obstacle-clearing and surface wiping experiment in a simulated disinfection environment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.3
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• pp.281-287
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• 2023

Establishing a ship's passage plan is an essential step before it starts to sail. The research related to the automatic generation of ship passage plans is attracting attention because of the development of maritime autonomous surface ships. In coastal water navigation, the land, islands, and navigation rules need to be considered. From the path planning algorithm's perspective, a ship's passage planning is a global path-planning problem. Because conventional global path-planning methods such as Dijkstra and A^* are time-consuming owing to the processes such as environmental modeling, it is difficult to modify a ship's passage plan during a voyage. Therefore, the D^* algorithm was used to address these problems. The starting point was near Busan New Port, and the destination was Ulsan Port. The navigable area was designated based on a combination of the ship trajectory data and grid in the target area. The initial path plan generated using the D^* algorithm was analyzed with 33 waypoints and a total distance of 113.946 km. The final path plan was simplified using the Douglas-Peucker algorithm. It was analyzed with a total distance of 110.156 km and 10 waypoints. This is approximately 3.05% less than the total distance of the initial passage plan of the ship. This study demonstrated the feasibility of automatically generating a path plan in coastal navigation for maritime autonomous surface ships using the D^* algorithm. Using the shortest distance-based path planning algorithm, the ship's fuel consumption and sailing time can be minimized.

• The Journal of Korea Robotics Society
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• v.3 no.4
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• pp.338-344
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• 2008

Most omni-directional mobile robots have to change their trajectory for avoiding obstacles regardless of the size of the obstacles. However, an omni-directional mobile robot having kinematic redundancy can maintain the trajectory while the robot avoids small obstacles. This works deals with the kinematic modeling and motion planning of an omni-directional mobile robot with kinematic redundancy. This robot consists of three wheel mechanisms. Each wheel mechanism is modeled as having four joints, while only three joints are necessary for creating the omni-directional motion. Thus, each chain has one kinematic redundancy. Two types of wheel mechanisms are compared and its kinematic modeling is introduced. Finally, several motion planning algorithms using the kinematic redundancy are investigated. The usefulness of this robot is shown through experiment.

• Journal of the Ergonomics Society of Korea
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• v.6 no.1
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• pp.25-32
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• 1987

The paesent paper deals with obtaining the properly mixed application critaeia for the manual mode, using computer graphic simulation, in order to recover the error effectively occurring in the advanced teleoperator work of man-robot system. In these experiments the error which is occurred during performing the automatic mode is recovered by the manual mode which is combined properly the operation by hyman with the operation by control program. The result shows an improvement availibility of the system by not only establishing an efficient combination of the manual mode according to trajectory planning but also recovering the error effectively. Therefore we suggest that the operation by control program should be applied in macro motion of control and the operation by human in micro motion of control.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1581-1584
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• 1997

This paper poropsed an efficient optimization technuque to resolve redundancy and a trajectory planning for a high precision control using proposed optimization technique. The proposed techniqus is the joint disturbance torque optimizatioin considering redundancy in the joing servo control. Joint disturbance torque is not unknown it is described dynamic equation ignored friction and viscosity. The proposed technique is used the dynamic equatiion included the joint disturbance torque characteristics. Numerical example of 3 joint planar redundant robot manipulator is simulated. In the 2-norm minimization of joint disturbance torque we compared pseudoinverse local optimization with proposed technique, and the results showed better the proposed technique. So the proposed technique can be highly precision controlled redundant robot manipulators in the joint servo control.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.4
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• pp.167-175
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• 2016

We present a method for improving adaptability of Learning from Demonstration (LfD) strategy by combining the LfD and Particle Swarm Optimization (PSO). A trajectory generated from an LfD is modified with PSO by minimizing a fitness function that considers constraints. Finally, the final trajectory is suitable for a task and adapted for constraints. The effectiveness of the method is shown with a target reaching task with a manipulator in three-dimensional space.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.40-43
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• 1996

An off-line programming, OLP, system is widely used in automation fines. To help an on-line robot system to carry out desirable tasks planned by the off-line simulation, an approach to the real-time communication is presented. The OLP system developed consists of a software, a host computer(PC), a SCARA robot body, four servo drivers, and four independent joint controllers. This study focuses on the software where real-time communication is included. The software, can be used in teaching, trajectory planning, real-time running, and performance evaluation. The evaluation of different control algorithms is one of the merits of the software. The software can give servo commands for task running. A comparison of generated and corresponding actual trajectories provides the evaluation of task performance. The safety, of the OLP system is ensured by alarming malfuntions of the system. The OLP system developed can reduce the teaching time and increase the user's convenience.

• 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.

• Journal of the Korean Institute of Intelligent Systems
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• v.6 no.2
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• pp.111-119
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• 1996

In this paper, we propose time-optimal trajectory planning algorithms for cooperative multi-robot manipulators system considering optimal load distribution. Internal forces essentially effect on time optimal trajectory planning and if they are comitted, the time optimal scheme is not no longer true. Therefore, we try to find the internal force factors of cooperative robot manipulators system in a time-optimal aspect. In this approach, a specific generalized inverse is used and is fuzzified for the purpose. In this optimal method, the fuzzy logic concept is used and selected for diminishing computation time, for finding the load distribution factors.