• 전기학회논문지
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• 제63권1호
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• pp.115-122
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• 2014

Mobile robot has been studied for long time due to its simple structure and easy modeling. Regarding path planning of the mobile robot, we suggest real-time hybrid path planning algorithm which is the combination of optimal path planning and real-time path planning in this paper. Real-time hybrid path planning algorithm modifies, finds best route, and saves calculating time. It firstly plan the route with real-time path planning then robot starts to move according to the planned route. While robot is moving, update the route as the best outcome which found by optimal path planning algorithm. Verifying the performance of the proposed method through the comparing real-time hybrid path planning with optimal path planning will be done.

• 한국CDE학회논문집
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• 제11권6호
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• pp.440-446
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• 2006

This study relates to the effect of forming time of injection path on the total process. The whole process can be divided into build process of forming path of injection and after treatment process. The total time required for the whole process could be reduced by reducing the forming time of injection path using SLC file to correct the problems of STL file that is the basic file format for high speed molding devices. First of all, I verify the forming time of injection path according to the conditions of STL file during the formation of injection path. And I verify problems using STL file during formation of injection path. And then I tried to solve problems of STL file by comparing between the formation time of injection path and the existing method using SLC files.

• 대한교통학회지
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• 제23권6호
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• pp.19-30
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• 2005

본 논문에서는 수집된 데이터를 이용한 경로통행시간 추정에 관한 연구를 수행하였다. 교통정보 이용자들은 출발지에서 목적지까지 통행하는데 소요되는 경로통행시간에 대해 다양한 정보를 요구하고 있다. 그러나 지금까지 경로통행시간 정보는 평균링크통행시간의 단순한 조합에 의한 평균경로통행시간의 단조로운 형태로 제공되고 있어 정보이용자들의 다양한 경로통행시간 정보에 대한 요구를 충족시키지 못하고 있는 실정이다. 이러한 획일적인 경로통행시간 정보제공의 문제점을 개선하기 위해 본 연구에서는 동일구간, 동일조건에서 여러 대표값으로 분포하는 경로통행시간에 대한 연구를 통하여 다양한 경로통행시간에 대한 정보를 제공함으로써 정보 이용자의 요구에 부응하기 위한 경로통행시간 추정에 관한 연구를 실시하였다. 본 연구에서는 링크통행시간의 조합을 통해 경로통행시간의 분포를 추정하기 위해 링크통행시간과 경로통행시간과의 관계를 분석하였다. 이러한 결과를 바탕으로 링크통행시간 분포비율을 조합하여 경로통행시간 분포비율을 추정하는 알고리즘을 구축하였으며, 알고리즘 적용결과 우수한 추정력을 가지는 것으로 분석되었다.

• Journal of Computational Design and Engineering
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• 제3권2호
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• pp.132-139
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• 2016

In this paper, a minimum time path planning strategy is proposed for multi points manufacturing problems in drilling/spot welding tasks. By optimizing the travelling schedule of the set points and the detailed transfer path between points, the minimum time manufacturing task is realized under fully utilizing the dynamic performance of robotic manipulator. According to the start-stop movement in drilling/spot welding task, the path planning problem can be converted into a traveling salesman problem (TSP) and a series of point to point minimum time transfer path planning problems. Cubic Hermite interpolation polynomial is used to parameterize the transfer path and then the path parameters are optimized to obtain minimum point to point transfer time. A new TSP with minimum time index is constructed by using point-point transfer time as the TSP parameter. The classical genetic algorithm (GA) is applied to obtain the optimal travelling schedule. Several minimum time drilling tasks of a 3-DOF robotic manipulator are used as examples to demonstrate the effectiveness of the proposed approach.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.25-29
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• 1997

In this thesis, we construct the microrobot succor system and navigate the real-time path planning and visual tracking of each robot. The system consists robots, vision system and a host computer. Because the robots are free-ranging mobile robot, it is needed to make and gallow the path. The path is planned and controlled by a host computer, ie. Supervisory control system. In path planning, we suggest a cost function which consists of three terms. One is the smoothness of the path, another is the total distance or time, and the last one is to avoid obstacles. To minimize the cost function, we choose the parametric cubic spline and update the coefficients in real time. We perform the simulation for the path planing and obstacle avoidance and real experiment for visual tracking

• 항공우주시스템공학회지
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• 제14권2호
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• pp.1-11
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• 2020

Detecting obstacles and generating a suitable path to avoid obstacles in real time is a prime mission requirement for UAVs. In areas, close to buildings and people, detecting obstacles in the path and estimating its own position (egomotion) in GPS degraded/denied environments are usually addressed with vision-based Simultaneous Localization and Mapping (SLAM) techniques. This presents possibilities and challenges for the feasible path generation with constraints of vehicle dynamics in the configuration space. In this paper, a near real-time feasible path is shown to be generated in the ORB-SLAM framework using a chain-based path planning approach in a force field with dynamic constraints on path length and minimum turn radius. The chain-based path plan approach generates a set of nodes which moves in a force field that permits modifications of path rapidly in real time as the reward function changes. This is different from the usual approach of generating potentials in the entire search space around UAV, instead a set of connected waypoints in a simulated chain. The popular ORB-SLAM, suited for real time approach is used for building the map of the environment and UAV position and the UAV path is then generated continuously in the shortest time to navigate to the goal position. The principal contribution are (a) Chain-based path planning approach with built in obstacle avoidance in conjunction with ORB-SLAM for the first time, (b) Generation of path with minimum overheads and (c) Implementation in near real time.

• 한국정밀공학회지
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• 제19권9호
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• pp.142-150
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• 2002

This study describes a method of finding an optimal path of a soccer robot by using a concentric circle method with different radii of rotation. Comparing with conventional algorithms which try to find the shortest path length, the variable concentric circle method find the shortest moving time. The radius fur the shortest moving time for a given ball location depends on the relative location between a shooting robot and a ball. Practically it is difficult to find an analytical solution due to many unknowns. Assuming a radius of rotation within a possible range, total path moving time can be calculated by adding the times needed for straight path and circular path. Among these times the shortest time is obtained. In this paper, a graphical solution is presented such that the game ground is divided into 3 regions with a minimum, medium, and maximum radius of rotation.

• Journal of information and communication convergence engineering
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• 제5권3호
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• pp.239-244
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• 2007

In the telematics system, a reasonable path search time should be guaranteed from a great number of user's queries, even though the optimal path with minimized travel time might be continuously changed by the traffic flows. Thus, the path search method should consider traffic flows of the roads and the search time as well. However, the existing path search methods are not able to cope efficiently with the change of the traffic flows and to search rapidly paths simultaneously. This paper proposes a new path search method for fast computation. It also reflects the traffic flows efficiently. Especially, in order to simplify the computation of variable heuristic values, it employs a simplification method for estimating values of traffic-adaptable heuristics. The experiments are carried out with the $A^*$ algorithm and the proposed method in terms of the execution time, the number of node accesses and the accuracy. The results obtained from the experiments show that the method achieves very fast execution time and the reasonable accuracy as well.

• 대한기계학회논문집A
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• 제37권5호
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• pp.609-617
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• 2013

본 논문은 무인 자율 주행을 위한 최소 시간 경로계획 알고리즘에 대해서 제안하였다. 최소 시간 경로계획 문제는 경로의 기하학적인 형상에 대한 고려뿐만이 아니라 차량 동역학까지 고려해야 하는 최적 문제이다. 경로계획은 후보 경로 생성 알고리즘과 속도 최적화 알고리즘으로 구성된다. 후보 경로 생성 알고리즘은 최단 거리 경로와 최고 속도 경로를 조합하여 후보경로를 생성한다. 속도 최적화 알고리즘은 차량의 주행성능 한계와 타이어 마찰 한계를 고려하여 각 후보 경로의 최고 속도를 계산한다. 이렇게 계산된 경로와 속도를 이용하여 각 후보 경로의 주행 시간을 계산하고 가장 작은 주행 시간의 경로를 최단시간 경로로 도출한다. 그리고 제안한 알고리즘은 CarSim 과 Matlab/Simulink 를 사용한 시뮬레이션을 통해 검증하였다.

• Journal of Nutrition and Health
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• 제34권6호
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• pp.701-714
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• 2001

The purpose of this study was to apply a PERT-type system, a combination of the project evaluation and review technique(PERT) and critical path method(CPM) on the employees' work time management of flood preparation, assembly, transportation and cleaning in home-delivered meals program for elderly The resources allotment heuristic program was developed by considering the number of employees and cooking utilities, being limited resources of home- delivered meals program. This program could assign the employees to perform the works included in flood preparation, assembly, transportation ind cleaning. Critical path and activities ware identified by PERT-type system on the basic of work time investigation in five senior centers. Work sheets were invented to perform the work by the shortest path with flexible employees'maximum flow As a result of the work time investigation, the most prevalent activities were ones of preparation in center C and E. Besides, the preparation(over fifty percent) was the most proportion among flood preparation, assembly, transportation and cleaning in center C and E. Critical path and activities of 'C'center were cucumber in sauce preparation path and assembly, wrapping in assembly path and case delivery in transportation path. Critical path and activities of 'E'center were Pan-fried Potato Preparation Path and assembly, case covering, wrapping in assembly Path. The work sheet invented by the heuristic program and PERT-type system reduced the work completion time and man hours in both centers.