Scheduling of flexible manufacturing systems based on Petri nets and hybrid heuristic search (original) (raw)
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Petri Net Models and Heuristic Search for Scheduling of Manufacturing Systems: A Comparative Study
2006
Petri Nets have been extensively used to model different types of manufacturing systems. However, the "state explosion" and the NP-hard nature of many scheduling problems related to such systems has prevented their use for optimization. Past approaches have attempted to partially search the net reachability graph with some promising results. In this paper, we propose an algorithm that combines the A* Search and the Beam Search algorithms for Petri Net scheduling. The primary purpose is to improve the search capability without compromising much the solution quality of the search method. Computational tests were conducted on classical job shop problems with known optimal solutions to investigate the performance of the algorithm. The algorithm is compared against dispatching rules and against the Beam Search algorithm. The results suggest that the Petri Net approach can be a powerful tool for optimization. This paper is organized as follows: First, concepts of modeling with Petri nets are introduced. Next in section 2, time-space state equations to track the net evolution are presented. In section 3, the BAS algorithm is described in detail. Section 4 presents the results of our experiments. Conclusions and further research are discussed in the last section.
Application of Petri Nets to Group Scheduling in Flexible Manufacturing Systems
IFAC Proceedings Volumes, 2001
The objective of this paper is to use deterministic timed Petri Nets to simulate jobscheduling problems for Flexible Manufacturing Systems (FMS). Job scheduling is a combinatorial optimization problem that is NP-hard. This paper discusses an approach that is heuristic in nature and achieves a sub-optimal schedule in two steps. The first step is to decompose the production system into a number of Cellular Manufacturing (CM) centers. The CM centers are essential to build a flexible manufacturing system. Grouping similar parts into a family tends to reduce the difficulty of the scheduling problem. The second step is the job scheduling of each family. Finally, a colored Petri nets is designed to simulate the schedule of one family of the parts with a graphical user interface. Also, the simulator can dynamically make in-process scheduling decision by solving conflicts for resources (workstation availability). Copyright ©2 0011FAC
… and Factory Automation, 2003. Proceedings. ETFA' …, 2003
This paper presents an approach to model and optimize the activities of a manufacturing workstation based on a Petri structure. To model the workstation activities a comprehensive hierarchical task decomposition consistent with manufacturing control requirements is followed. We also introduce the concept of time-state equations for tracking and optimization purposes. In order to optimize the flow of parts through the physical workstation, a method that combines the heuristic A* search algorithm with limited marking expansion, a new heuristic function and a "non-delay" branching scheme is presented. The output of the algorithm is a near-optimal solution to the part scheduling problem under the makespan criterion. A comparison against previous work shows promising results.
The objective of this paper is a study of minimizing the maximum completion time min F max , or cycle time of the last job of a given family of jobs using¯ow shop heuristic scheduling techniques. Three methods are presented: minimize idle time (MIT); Campbell, Dudek and Smith (CDS); and Palmer. An example problem with ten jobs and ®ve machines is used to compare results of these methods. A deterministic t-timed colored Petri net model has been developed for scheduling problem. An execution of the deterministic timed Petri net allows to compute performance measures by applying graph traversing algorithms starting from initial global state and going into a desirable ®nal state(s) of the production system. The objective of the job scheduling policy is minimizing the cycle time of the last job scheduled in the pipeline of a given family of jobs. Three heuristic scheduling methods have been implemented. First, a sub-optimal sequence of jobs to be scheduled is generated. Second, a Petri net-based simulator with graphical user interface to monitor execution of the sequence of tasks on machines is dynamically designed. A deterministic t-timed colored Petri net model has been developed and implemented for¯exible manufacturing systems (FMS). An execution of the deterministic timed Petri net into a reachability graph allows to compute performance measures by applying graph traversing algorithms starting from initial global state to a desirable ®nal state(s) of the production system.
2007 Science Publications A Scheduling Algorithm Based on Petri Nets and Simulated Annealing
American Journal of Applied Sciences
This study aims at presenting a hybrid Flexible Manufacturing System “HFMS ” short-term scheduling problem. Based on the art state of general scheduling algorithms, we present the metaheuristic, we have decided to apply for a given example of HFMS. That was the study of Simulated Annealing Algorithm SA. The HFMS model based on hierarchical Petri nets, was used to represent static and dynamic behavior of the HFMS and design scheduling solutions. Hierarchical Petri nets model was regarded as being made up a set of single timed colored Petri nets models. Each single model represents one process which was composed of many operations and tasks. The complex scheduling problem was decomposed in simple sub-problems. Scheduling algorithm was applied on each sub model in order to resolve conflicts on shared production resources.
IJERT-The Performance Study of Flexible Manufacturing Systems using Hybrid Algorithm Approach
International Journal of Engineering Research and Technology (IJERT), 2021
https://www.ijert.org/the-performance-study-of-flexible-manufacturing-systems-using-hybrid-algorithm-approach https://www.ijert.org/research/the-performance-study-of-flexible-manufacturing-systems-using-hybrid-algorithm-approach-IJERTV10IS060156.pdf The goal of today's production strategy is to maximize the advantages of flexibility. Only when a manufacturing system is completely controlled by FMS technology is this possible. With the Process-Product Matrix in mind, it's feasible to see how an industry might achieve high flexibility via creative technological and organizational initiatives. A flexible cell is now defined as two or more CNC machines, while a flexible manufacturing system is defined as two or more cells. In computer science, system engineering, and many other areas, Petri nets are a strong modeling framework. Petri nets are a graphical description of the dynamic behavior of systems that combines a well-defined mathematical theory with a graphical representation of the dynamic behavior of systems. Because each of its aspects may be implemented in a number of ways and with varying degrees of complexity, the scatter search process is very adaptable. To handle scheduling challenges, the Petri Net idea is introduced and compared to the Scatter Search method. When the results of two case studies (9 machines X 2 jobs) are examined, it is shown that Petri Net outperforms Scatter Search in terms of machine usage.
Adaptable Manufacturing System (FMS) is an automated gathering structure which has the work shop flexibility and stream shop efficiency. One of the genuine stresses in FMS is reserving of occupations to the machines with the objective of extending machine utilize. A Petri net is a graphical logical showing instrument proper to various systems and this is a promising gadget for depicting and thinking about information taking care of structures that are portrayed as being synchronous, non-simultaneous scattered, parallel, nondeterministic and stochastic. The Petrinet thought is proposed to deal with booking issues. Scatter Search figuring is masses based met heuristic that used to join its answers and grow new game plans. This strategy makes a masses of courses of action. The dispatching rules estimation has accepted a vital part in the passage of occupation to the machine according to the need of given decided parameter. Dispatching Rules look like Shortest Processing Time (SPT), Longest Processing Time (LPT), Least Operation Remaining (LOR), Most Work Remaining (MWR), Most Operation Remaining (MOR) and Least Work Remaining (LWR). This paper oversees exhibiting and booking of Flexible Manufacturing System (FMS) using various Meta Heuristics computations like Petrinet, Dispatching Rules and Scatter Search. The results are considered for three particular relevant examinations and it is watched that the Petrinet gives a better result when differentiated and diverse figurings, for instance, Dispatching Rules and Scatter Search estimation concerning machine use.
Petri net dynamics-based scheduling of flexible manufacturing systems with assembly
Journal of Intelligent Manufacturing, 1999
This paper presents a heuristic search method based on Petri nets for scheduling flexible manufacturing systems with assembly (FMSA) by partially generating the reachability graph. FMSAs are modeled by two types of timed place Petri nets, called generalized symmetric (GSN) and asymmetric nets (GAN). GSN is a sub-class of GAN. The special Petri net structures of GSN and GAN allow
WSEAS Transaction on Systems
In this paper a flexible manufacturing system is investigated where the production process is accomplished in two main stages: machining and assembling. For Modeling of the system the timed Petri net is used. The minimum time requirement for completing the machining is discussed so that assembling the parts would be performed at the possible least time. Scheduling the manufacturing system is performed via a Petri net based controller supervised by a branch and bound algorithm. Also for speeding up the running of algorithm a new method is introduced which doesn't need large memory. The proposed approaches are verified through simulation results.