Font Size: a A A

Formal Design Method Of Coordinating Controller For Automated Guided Vehicle Systems

Posted on:2018-04-26Degree:MasterType:Thesis
Country:ChinaCandidate:Q ZhangFull Text:PDF
GTID:2348330536472498Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
With the rapid development of intelligent manufacturing and modern logistics industry,automatic guided vehicle(AGV)is extensively used in intelligent manufacturing workshops,automatic ports,three-dimensional warehouses and other automation areas.AGVs have the advantages of good flexibility and high degree of automation.When there are multiple AGVs running in the system,it is necessary to consider the coordinating control problem between vehicles.How to solve the problems of the reliability,rapid development and maximum permissions for control programs in an AGV system need much research to obtain sound solutions.To avoid collision and deadlock in an AGV system,this work presents the design methods of a coordinating controller by directed graphs and labeled Petri nets.The main contents of this paper are summarized as follows:1.A method is proposed to design a coordinating controller based on directed graphs.Firstly,a method is obtained to model an AGV system by directed graphs.Then,in order to solve the problem of collisions between vehicles,a method is given for estimating the number of vehicles in a dangerous area of a guiding line,and,in turn,an anti-collision control specification is formalized for a guiding line.Further,in order to realize the reliability and rapid development of the control program in an AGV system,a transformation method is proposed to translate the directed graphs model of an AGV system into a ladder-diagram program.In order to prevent deadlocks,two decision theorems of deadlock and a deadlock prevention algorithm are given.Finally,a design method of a coordinating controller based on directed graphs is obtained.2.A method is proposed to design a coordinating controller based on labeled Petri nets.Firstly,a method is obtained to model an AGV system by labeled Petri nets.Then,a method is given to enumerate all possible states that the system reaches from an observation sequence.In turn,it is utilized to compute a maximum permissible control for a given observation sequence.In order to prevent deadlocks,a decisiontheorem of deadlock and a deadlock prevention algorithm are given.Finally,a design method of a maximum permissible coordinating controller based on labeled Petri nets is obtained.The methods proposed in this paper are illustrated by an example,and verified by simulation experiments developed in Matlab.
Keywords/Search Tags:Automatic Guided Vehicle, Directed Graphs, Labeled Petri Nets, Coordinating Controller
PDF Full Text Request
Related items