Re-scheduling of AGVs Steady State Flow

RUTCOR Research Report RRR03-2011, 2011

There are many different types of FMSs. One of the simplest one is called Single-Stage Multi-machine System (SSMS). It consists of identical parallel work centers, a load/unload station, a material handling system and central tool magazine with a dedicated tool transportation system. SSMS has been investigated since the early 1990s. If the tool system is not a bottleneck then the main problem in scheduling an SSMS is that the schedules of the production and material handling systems must be harmonized, i.e. the best schedule of the production system must be determined such that it still can be served by the material handling system. The schedule of the SSMS has been addressed by some previous papers. But they scheduled either the production regardless the transportation system, or scheduled the transportation system only if the production had been already scheduled. The main contribution of the present paper is that a new single method is developed to schedule both the production and the material handling system simultaneously. All parts arrive to the assigned machine in time and the makespan is minimized. The two scheduling activities are not separated but they are done in the frame of the same algorithm.

2003

AbstractDue to the increasing popularity of automated guided vehicles in modern indus-tryandthevaluableinvestmenttheyrequire,theirdesignandoperationalissueshavebeenstudiedextensivelyinrecentliterature. Ontheotherhand,machineschedulingremainsanactiveresearchareasinceseveraldecades. However,materialhandlingop-erationsshouldbesynchronizedwithmachineoperationstogetabetterutilizationofresources. In this article, we optimally solve an integrated production and materialhandling scheduling problem in a job-shop context. A mathematical programmingmodelandaconstraintprogrammingmodelarepresentedfortheproblemandtestedonproblemsfromtheliterature. Oneofk-shortestpathsbetweeneverytwomachinesmaybeusedforamaterialhandlingoperationoradeadhead. Whenapathischosen,allitssegmentsaremobilizeduntiltheendofthehandlingoperationorthedeadhead.A commercial software (ILOG OPLStudio) was used for modeling and solving bothmodels.Keywords: Integratedscheduling,conflict-freerouting,materialhandling,produc-tion,mixedi...

Mathematical Problems in Engineering, 2013

The paper concerns cyclic scheduling problems arising in a Multimodal Transportation Network (MTN) in which several unimodal networks (AGVs, hoists, lifts, etc.) interact with each other via common shared workstations as to provide a variety of demandresponsive material handling operations. The material handling transport modes provide movement of work-pieces between workstations along their manufacturing routes in the MTN. The goal is to provide a declarative framework enabling to state a constraint satisfaction problem aimed at AGVs fleet match-up scheduling taking into consideration assumed itineraries of concurrently manufactured product types. In that context, treating the different product types as a set of cyclic multimodal processes is the main objective to discuss the conditions sufficient for FMS rescheduling imposed by production orders changes. To conclude, the conditions sufficient for an FMS rescheduling imposed by changes of production orders treated as cyclic multimodal processes are stated as the paper's main contribution.

IFAC Proceedings Volumes, 1992

This paper is an attempt to make the AGV scheduling an integral par t of the overall scheduling activity in an FMS environment. The sequence-dependent nature of travel times for the deadheading trips between successive loaded trips of the AGVs increases the problem difficulty. The problem is decomposed into two subproblems I and an iterat ive solution procedure is developed where the operation completion times obtained from the machine schedule subproblem by means of an heuristic are used to construct time windows for each material handling trip in the vehicle scheduling subproblem which is handled as a sliding time window problem.

2018

Author(s): Chassiakos, Anastasios; Jula, Hossein; VanderBeek, Timothy | Abstract: This work studies the optimization of scheduling of chassis and container movements at the operational level for individual trucking companies when Chassis Processing Facilities (CPFs) are available for use in the vicinity of a container port within a major metropolitan area. A multi-objective optimization problem is formulated in which the weighted combination of the total travel time for the schedules of all vehicles in the company fleet and the maximum work span across all vehicle drivers during the day is minimized. Time-varying dynamic models for the movements of chassis and containers are developed to be used in the optimization process. The optimal solution is obtained through a genetic algorithm, and the effectiveness of the developed methodology is evaluated through a case study which focuses on the Los Angeles/Long Beach port complex. The case study uses a trucking company located in the Los ...

Acknowledgement x Chapter 1 Introduction 1 1.1 Background and Motivation 1 1.2 General Research Aims 3 1.3 Research Goals 4 1.4 Dissertation Organization 5 Chapter 2 Literature Review and Problems Description 8 2.1 Realizing Distributed Control Paradigm using Holonic Manufacturing System 2.1.1 Introduction of Holonic Manufacturing System 2.1.2 Holonic Manufacturing System Architecture 9 9 9 2.2 Deployment of Automated Guided Vehicle (AGV) as MTS in Manufacturing Industry 2.2.1 MTS for Manufacturing Industry 2.2.2 Overview on AGV Technologies ii 2.2.3 Scheduling and Routing of Autonomous AGVs using Vehicle Routing Problem 2.2.4 Performance Measurements of MTS in a Manufacturing Industry 2.3 Developing Autonomous Control System based on Multi Agent Architecture 2.3.1 Principle of Intelligent Agent 2.3.2 Types of Multi Agent Architecture 2.3.3 Fundamental of Contract Net Protocol (CNP) 2.3.4 Agent Standards and Interoperability

International Journal of Production Research, 1999

Automated Guided Vehicles (AGVs) are now becoming popular in automated materials handling systems, flexible manufacturing systems and even containers handling applications at seaports. In the past two decades, much research and many papers have been devoted to various aspects of the AGV technology and rapid progress has been witnessed. As one of the enabling technologies, scheduling and routing of AGVs have attracted considerable attention; many algorithms about scheduling and routing of AGVs have been proposed. However, most of the existing results are applicable to systems with small number of AGVs, offering low degree of concurrency. With drastically increased number of AGVs in recent applications (e.g.

Computer Aided Chemical Engineering, 2006

The efficient coordination of production and distribution systems has received increasing attention as companies move towards higher collaborative and competitive environments. This work focuses on the operational level of Supply Chain Management (SCM) to efficiently coordinate the short-term production and transport scheduling. The production and transport systems are modeled as detailed scheduling problems using a novel MILP formulation based on a continuous-time representation. A hybrid MILPheuristic approach is also presented to reduce the inherent combinatorial complexity of the problem.

hicss, 2000

Multi-site scheduling deals with the scheduling problems of an enterprise with several distributed production sites, where sites are using the intermediate products of other sites to manufacture the products of the enterprise. Therefore the transportation of the raw materials and the intermediate products to the plants is an important task within the whole process of manufacturing. Scheduling problems are treated on two levels. On the global level a global schedule is generated including the requirements for the local level schedulers which then have to transform the global schedule into a local schedule for manufacturing. Since transportation is a vital task in the multi-site scenario, we will view it as a scheduling task on the local level as well. Besides the "classical" objectives of transportation tasks such as finding shortest paths or minimizing costs the temporal restrictions of meeting the delivery dates here are the most important goals. In this paper we describe how transportation tasks can be modeled as a scheduling problem and which kind of solution strategies are appropriate.

The International Journal of Advanced Manufacturing Technology, 2011

Scheduling of flexible manufacturing systems is a well-known NP-hard problem which is very complex, due to additional considerations like material handling, alternative routing, and alternative machines. Improvement in the performance of a flexible manufacturing system can be expected by efficient utilization of its resources, by proper integration and synchronization of their scheduling. Differential evolution is a powerful tool which proved itself as a better alternative for solving optimization problems like scheduling. In this paper, the authors addressed simultaneous scheduling of both machines and material handling system with alternative machines for the makespan minimization objective. The authors proposed a machine selection heuristic and a vehicle assignment heuristic which are incorporated in the differential evolution approach to assign the tasks, to appropriate machine and vehicle, and to minimize cycle time.