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Guide Path Design for Automated Guided Vehicles

Kazemi, Morteza | 2009

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 39201 (01)
  4. University: Sharif University of Technology
  5. Department: Industrial Engineering
  6. Advisor(s): Eshghi, Koorosh; Asef Vaziri, Ardavan
  7. Abstract:
  8. Around 20 to 50 percent of the operation costs occurs in manufacturing is related to facility layout. Efficient design would reduce these costs by 10 to 30 percent. Facility layout consists of design of material handling system and plant layout. Design of material handling system includes determining, the flow network and locations of Pick-up and Delivery stations which are defined regarding to the kind of material handling equipment. Today, Automated Guided Vehicles are considered as the basic material handling equipment due to their potentials in production planning and controls, high safety and flexibility and low expenses.
    In this thesis, we first discuss the design of the shortest loop in a block layout. The Shortest loop can be considered as an applicable solution for AGV's path when the material flow between work centers has stochastic behavior. To solve the problem, we show that finding a feasible loop in block layout is equivalent to find a special type subgraph in dual graph of the layout. Therefore, we develop an MIP model and an ACO heuristic algorithm. In design of the shortest loop, an AGV trip distance is not considered. To be more practicable the design of network flow, we design an enhanced loop flow with determination of pick-up and delivery stations. The objective is to minimize the total loaded and unloaded trip distances. To obtain more realistic results, the stations are located in the intermediate nodes to control the traffics of the vehicles and avoid collision of AGV's. To solve this problem, we develop a global model, two simplifications and a heuristic algorithm on the basis of the Ant Colony Optimization algorithm. The results show that heuristic algorithm quickly generates close to optimal solutions for the global model. Besides loop pattern, bidirectional shortest path is the other simple pattern to design AGVs guide path. We first show that finding the shortest bidirectional path is equivalent to find the shortest generalized minimum spanning tree with side constraints in the extended network flow graph. So the lower bound of the problem can be obtained by polynomial algorithm with Lagrangian relaxation method. Moreover, by utilizing the heuristic algorithm of finding shortest loop, we develop an algorithm to find upper bound of the problem. By using a lower and upper bound, an efficient branch and bound algorithm is developed to obtain the optimal path.
  9. Keywords:
  10. Materials Handling ; Automated Guided Vehicles (AGV) ; Heuristic Algorithm ; Guide Path ; Path Planning ; Facility Layout ; Loop Guide Path

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