• 한국지능시스템학회논문지
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• 제26권3호
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• pp.169-175
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• 2016

최근 다양한 환경에서 지능형 로봇의 안정된 이동과 작업계획에 대한 연구가 이루어지고 있다. 본 논문에서는 상하 결합가능한 구조의 4족 로봇의 설계 및 작업 계획방법을 제안한다. 제안하는 4족 로봇은 리니어 모터를 이용하여 다리 길이를 조절하고, 팔각뿔 형태의 도킹모듈을 이용하여 상하 결합과 분리가 가능하도록 설계하였다. 또한 로봇이 다양한 환경에서 안정된 이동과 정보 수집을 위하여 지자기 센서, PSD 센서, LRF 센서와 카메라를 사용하였다. 리니어 모터를 이용한 장애물 회피 동작방법과 상하 결합 동작방법을 제안하고 구현하였다. 로봇은 다리 길이를 조절하여 장애물을 극복하고, 두 대의 로봇이 상하 결합을 통하여 협력 작업방법을 제안하였다. 두 대의 4족 로봇이 상하 결합을 통하여 4족과 6족 보행을 하고, 상부 결합 로봇의 4개의 다리를 4개의 팔 또는 2개의 팔로 사용할 수 있으며, 결합된 로봇을 이용하여 물건 옮기기 작업을 구현하고, 각 동작들을 실제 실험으로 기능을 검증하였다.

• 로봇학회논문지
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• 제19권2호
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• pp.196-202
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• 2024

The ability to understand given environments and plan a sequence of actions leading to goal state is crucial for personal service robots. With recent advancements in deep learning, numerous studies have proposed methods for state representation in planning. However, previous works lack explicit information about relationships between objects when the state observation is converted to a single visual embedding containing all state information. In this paper, we introduce graph-based state representation that incorporates both object and relationship features. To leverage these advantages in addressing the task planning problem, we propose a Graph Neural Network (GNN)-based subgoal prediction model. This model can extract rich information about object and their interconnected relationships from given state graph. Moreover, a search-based algorithm is integrated with pre-trained subgoal prediction model and state transition module to explore diverse states and find proper sequence of subgoals. The proposed method is trained with synthetic task dataset collected in simulation environment, demonstrating a higher success rate with fewer additional searches compared to baseline methods.

• 전자공학회논문지B
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• 제30B권10호
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• pp.50-58
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• 1993

The problem of trajectory planning in two redundant robot systems is considered. The trajectory of each robot for the cooperative task is generated so that the robots assume their optimal configurations while following a given desired task. The cooperative task compatibility in and the weighted sum of manipulabilities are proposed and investigated as quality measures. The cooperative task compatibility includes the velocity and force transmission charateristics to the task requirements and so it measures the compatibilities of robot postures with respect to a given task. The weighted sum of manipuabilities of robot postures with respect to a given task. The weighted sum of manipulabilities is also considered as a quality measure since it is helpful to avoid singularities. The usefulness of the cooperative task compatibility and the weighted sum of manipulabilities are shown by computer simulation studies.

• 한국정밀공학회지
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• 제15권4호
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• pp.111-117
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• 1998

In order to increase productivity of an assembly system composed of multiple robots along a conveyer line, an efficient sequence planning is necessary because the assembly time is dependent upon the assembly sequence. In this paper, a two-robot assembly system is considered in which two robots operate simultaneously and transfer parts from the part feeders to the workpiece on the conveyer one by one. In this case, the distance from the feeder to the workpiece varies with time because the workpiece moves at a constant speed on the conveyer. Hence, the sequence programming is not a trivial problem. Also, the two robots may interfere with each other kinematically and dynamically due to the simultaneous operation, so the sequence should be programmed to avoid the interferences. In this paper, the task sequence optimization problem is formulated and is solved by employing the simulated annealing which has been shown to be effective for solving large combinatorial optimizations.

• 대한임베디드공학회논문지
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• 제9권2호
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• pp.101-107
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• 2014

Mobile robots use an environment map of its workspace to complete the surveillance task. However grid-based maps that are commonly used map format for mobile robot navigation use a large size of memory for accurate representation of environment. In this reason, grid-based maps are not suitable for path planning of mobile robots using embedded board. In this paper, we present the path planning algorithm that produce a secure path rapidly. The proposed approach utilizes a hybrid map that uses less memory than grid map and has same efficiency of a topological map. Experimental results show that the fast path planning uses only 1.5% of the time that a grid map based path planning requires. And the results show a secure path for mobile robot.

• 로봇학회논문지
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• 제18권1호
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• pp.10-17
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• 2023

Recently, robots have been actively utilized for logistics and delivery services in various places such as restaurants, hotels, and hospitals. In addition, it provides a safer environment, convenience, and cost efficiency to the customers. However, when it comes to autonomous delivery in a multi-floor environment, the task is still challenging. Especially for wheeled mobile robots, it is necessary to deal with elevators to perform the last-mile delivery services. Therefore, we present a multi-floor route planning algorithm that enables a wheeled mobile robot to traverse an elevator for the delivery service. In addition, an elevator boarding mission algorithm was developed to perceive the drivable region within the elevator and generate a feasible path that is collision-free. The algorithm was tested with real-world experiments and was demonstrated to perform autonomous postal delivery service in a multi-floor building. We concluded that our study could contribute to building a stable autonomous driving robot system for a multi-floor environment.

• 제어로봇시스템학회논문지
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• 제10권4호
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• pp.350-356
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• 2004

This paper presents a farce manipulability analysis of multi-legged walking robots, which calculates force or acceleration workspace attainable from joint torque limits of each leg. Based on the observation that the kinematic structure of the multi-legged walking robots is basically the same as that of multiple cooperating robots, we derive the proposed method of analyzing the force manipulability of walking robot. The force acting on the object in multiple cooperating robot systems is taken as reaction force from ground to each robot foot in multi-legged walking robots, which is converted to the force of the body of walking robot by the nature of the reaction force. Note that each joint torque in multiple cooperating robot systems is transformed to the workspace of force or acceleration of the object manipulated by the robots in task space through the Jacobian matrix and grasp matrix. Assuming the torque limits are given in infinite norm-sense, the resultant dynamic manipulability is derived as a polytope. The validity of proposed method is verified by several examples, and the proposed method is believed to be useful for the optimal posture planning and gait planning of walking robots.

• 전자공학회논문지B
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• 제28B권5호
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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.

• 로봇학회논문지
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• 제16권1호
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• pp.56-63
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• 2021

As the use of robots in service area increases, research has been conducted to replace human tasks in daily life with robots. Among them, this study focuses on the tidy-up task on a desk using a robot arm. The order in which tidy-up motions are carried out has a great impact on the success rate of the task. Therefore, in this study, a neural network-based method for determining the priority of the tidy-up motions from the input image is proposed. Reinforcement learning, which shows good performance in the sequential decision-making process, is used to train such a task planner. The training process is conducted in a virtual tidy-up environment that is configured the same as the actual tidy-up environment. To transfer the learning results in the virtual environment to the actual environment, the input image is preprocessed into a segmented image. In addition, the use of a neural network that excludes unnecessary tidy-up motions from the priority during the tidy-up operation increases the success rate of the task planner. Experiments were conducted in the real world to verify the proposed task planning method.

• 제어로봇시스템학회논문지
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• 제19권5호
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• pp.435-441
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• 2013

A swarm robot system consists of with multiple mobile robots, each of which is called an agent. Each agent interacts with others and cooperates for a given task and a given environment. For the swarm robotic system, the loss of the entire work capability by malfunction or damage to a single robot is relatively small and replacement and repair of the robot is less costly. So, it is suitable to perform more complex tasks. The essential component for a swarm robotic system is an inter-robot collaboration strategy for teamwork. Recently, the swarm intelligence theory is applied to robotic system domain as a new framework of collective robotic system design. In this paper, FA (Firefly Algorithm) which is based on firefly's reaction to the lights of other fireflies and their social behavior is employed to optimize the group behavior of multiple robots. The main application of the firefly algorithm is performed on path planning of swarm mobile robots and its effectiveness is verified by simulations under various conditions.