• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.638-647
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• 1996

Robot manipulators for harvesting fruits must be controlled to track the desired path of end-effector to avoid obstacles under the consideration of collision free area and safety path. This paper presents a robot path control algorithm to secure a collision free area with the recognition of work environments. The flexible space, which does not damage fruits or branches of tree due to their flexibility and physical properties , extends the workspace. Now the task is to control robot path in the extended workspace with the consideration of collision avoidance and velocity limitation at the time of collision concurrently. The feasibility and effectiveness of the new algorithm for redundant manipulators were tested through simulations of a redundant manipulator for different joint velocities.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.418-418
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• 2000

This paper proposes a path planning algorithm for mobile robot. To generate an optimal path and minimum time path for a mobile robot, we use the Genetic Algorithm(GA) and Visibility Graph. After finding a minimum-distance between start and goal point, the path is revised to find the minimum time path by path-smoothing algorithm. Simulation results show that the proposed algorithms are more effective.

• 제어로봇시스템학회논문지
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• 제17권7호
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• pp.651-658
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• 2011

An efficient modified $D^*$ lite algorithm is suggested, which can perform online path planning for mobile robots in dynamic indoor environment. Online path planning should plan and execute alternately in a short time, and hence it enables the robot avoid unknown dynamic obstacles which suddenly appear on robot's path. Based on $D^*$ Lite algorithm, we improved representation of edge cost, heuristic function, and priority queue management, to build a modified $D^*$ Lite algorithm. Performance of the proposed algorithm is revealed via extensive simulation study.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1496-1499
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• 2004

In this paper, we deal with a novel path planning algorithm to find collision-free path for a moving robot to find an appropriate path from initial position to goal position. The robot should make progress by avoiding obstacles located at unknown position. Such problem is called the path planning. We propose so called the subgoal generation algorithm to find an effective collision-free path. The generation and selection of the subgoal are the key point of this algorithm. Several subgoals, if necessary, are generated by analyzing the map information. The subgoal is the candidate for the final path to be pass through. Then selection algorithm is executed to choose appropriate subgoal to construct a correct path. Deep and through explanations are given for the proposed algorithm. Simulation example is given to show the effectiveness of the proposed algorithm.

• 한국통신학회논문지
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• 제30권7B호
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• pp.481-488
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• 2005

멀티미디어 응용 서비스에 대한 요구가 증대됨에 따라 멀티미디어 혼잡제어 알고리즘에 대한 연구가 더욱 중요시되고 있다. 그러나 기존에 제안된 혼잡제어 알고리즘들은 혼잡 상황 판단을 위하여 RTT를 사용하기 때문에 데이터 전송 경로의 혼잡 상황과 회신 정보 회신 경로의 혼잡 상황을 정확히 구분하지 못하는 단점이 있다. 본 논문에서는 OTT를 사용하여 네트워크 혼잡 상황을 판단하도록 제안된 RRC-OTT(Receiver-based Rate Control with One-way Trip Time) 알고리즘의 장점을 활용하여 데이터 전송 경로와 회신 정보 회신 경로의 혼잡 상황 판단을 분리하도록 하였고, 특히 회신 경로의 혼잡 상황이 데이터 전송 경로에 미치는 영향을 최소화하는 알고리즘을 제안하였다. 제안된 알고리즘의 성능 평가를 통하여 기존 혼잡제어 알고리즘과 달리 RRC-OTT 알고리즘은 회신 경로의 혼잡 상황에 영향을 받지 않고 일정한 성능을 보임을 입증하였다.

• Journal of Mechanical Science and Technology
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• 제16권2호
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• pp.137-146
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• 2002

In this paper, a path generation algorithm that uses sensor scannings is described. A scanning algorithm for recognizing the ambient environment of the Automatic Guided Vehicle (AGV) that uses the information from the sensor platform is proposed. An algorithm for computing the real path and obstacle length is developed by using a scanning method that controls rotating of the sensors on the platform. The AGV can recognize the given path by adopting this algorithm. As the AGV with two-wheel drive constitute a nonholonomic system, a linearized kinematic model is applied to the AGV motor control. An optimal controller is designed for tracking the reference path which is generated by recognizing the path pattern. Based on experimental results, the proposed algorithm that uses scanning with a sensor platform employing only a small number of sensors and a low cost controller for the AGV is shown to be adequate for path generation.

• 한국생산제조학회지
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• 제22권2호
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• pp.256-262
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• 2013

This paper presents a linear path control algorithm for NeuroMate robot in a skull drilling system. For the path control inverse kinematics of the robot is analyzed and a linear interpolation algorithm is presented. A geometric approach is used for solving inverse kinematic equations for the robot. Four feasible solutions are found through the approach. The approach gives geometric insights for selecting the best solution from the feasible solutions. The presented linear interpolation algorithm computes a next position considering current velocity and remaining distance to the target position. Presented algorithm is implemented and tested in a skull drilling system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.100-103
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• 2005

In this study, tool path control algorithm for aspherical surface grinding was derived and discussed. The aspherical surface actually means contact points between lens and tool. Tool positions are generally defined at the center of a tool, so there is difference between tool path and lens surface. The path was obtained from contact angle and relative position from the contact point. The angle could be calculated after differentiating an aspheric equation and complex algebraic operations. The assumption of the control algorithm was that x moves by constant velocity while z velocity varies. X was normal to the radial direction of lens, but z was tangential. The z velocities and accelerations were determined from current error and next position in each step. In the experiment, accuracy of the control algorithm was checked on a micro-precision machine. The result showed that the control error tended to be diminished when the tool diameter increased, and the error was under sub-micro level.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1189-1192
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• 1996

Navigation is a science of directing a mobile robot as traversing the environment. The purpose of navigation is to reach a destination without getting lost or crashing into any obstacles. In this paper, we use a genetic algorithm for navigation. Genetic algorithm searches for path in the entire, continuous free space and unifies global path planning and local path planning. It is the efficient and effective method when compared with navigators using traditional approaches.

• Journal of Advanced Marine Engineering and Technology
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• 제23권6호
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• pp.731-737
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• 1999

This paper describes the path tracking control for a mobile robot which has two casters at the front and rear to keep balance and two driving wheels on the left and right sides of its body. Power wheeled steering method is adapted to control heading of the robot. It is very difficult to find appropriate feedback gains when linear regulator control scheme is adapted to path tracking con-trol of this type of robot. Therefore in this paper we propose the path tracking control algorithm using the fuzzy logic control scheme for this type of root. Simulation to prove the validity of the proposed two algorithms is performed. The results are reported as last part in this paper.