**7. References**


[8] Park J, Reveliotis SA. Algebraic synthesis of efficient deadlock avoidance policies for sequential resource allocation systems IEEE Trans Autom Control. 2000;16(2):190-195.

72 Petri Nets – Manufacturing and Computer Science

of all these methods.

**Author details** 

**Acknowledgement** 

Yen-Liang Pan

**7. References** 

580.

2007;37(4):517-526.

underlying notion of the prior work is that many inequalities (i.e. MTSIs) must be solved to prevent legal markings from entering the illegal zone in the original PN model. One must generate all MTSIs in a reachability graph and require high computation. This work proposes and uses CMTSI to overcome the computational difficulty. The detail information is also obtained in existing literatures.26-29 The proposed method can reduce the number of inequalities and thus the computational cost very significantly since CMTSIs are much less than MTSIs in large models. Consequently, it is optimal with much better computational efficiency than those existing optimal policies12-13, 16. More benchmark studies will be desired to establish such computational advantages of the proposed one over the prior ones. It should be noted that the problem is still NP-hard the same as other optimal policies due to the need to generate the reachability graph of a Petri net. The future research is thus much needed to overcome the computational inefficiency

*Department of Avionic Engineering, R.O.C. Air Force Academy, Taiwan, R.O.C.* 

IEEE Trans Syst Man Cybern A Syst Humans, 2004;34(1):5-22.

IEEE Trans Syst Man Cybern B Cybern. 1997;27(2):169-183.

Jun 25-27; Arlington, VA, USA. P. 4943-8. (ISBN:0-7803-6495-3)

and siphons Int J Prod Res. 2001;39(2):283-305.

The author is grateful to Prof. Yi-Sheng Huang and Prof. MengChu Zhou whose comments and suggestions greatly helped me improve the presentation and quality of this work.

[1] Fanti MP, Zhou MC. Deadlock control methods in automated manufacturing systems.

[2] Murata T. Petri nets: Properties, analysis and applications. In Proc IEEE. 1989;77(4):541-

[3] Ezpeleta J, Colom JM, Martinez J. A Petri net based deadlock prevention policy for flexible manufacturing systems. IEEE Trans Robot Autom. 1995;11(2):173-184. [4] Jeng MD. A Petri net synthesis theory for modeling flexible manufacturing systems.

[5] Huang YS, Jeng MD, Xie XL, Chung SL. Deadlock prevention policy based on Petri nets

[6] Li ZW, Hu HS, Wang AR. Design of liveness-enforcing supervisors for flexible manufacturing systems using Petri nets. IEEE Trans Syst Man Cybern C Appl Rev.

[7] Iordache MV, Moody JO, Antsaklis PJ. A method for the synthesis liveness enforcing supervisors in Petri nets. Procceedings of the 2001 American Control Conference; 2011

	- [25] INA. (Integrated Net Analyzer), A Software Tool for Analysis of Petri Nets. Version 2.2, 31.07. 2003. [Online]. Available: http://www.informatik.hu-berlin.de/~starke/ina.html.

**Chapter 4** 

© 2012 Yasuda, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Yasuda, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

In programming by the well-known teaching-playback or teaching by showing, the programmer specifies a single execution for the robot: there are no loops, no conditionals, no data retrieval, nor computations. This method can be implemented without a generalpurpose computer, and it is especially adequate for some applications, such as spot welding, painting, and simple materials handling. In other applications such as mechanical assembly

Because of the generality of the robot's physical structure, control and reprogrammability, it is expected that more and more robots will be introduced into industry to automate various operations. This flexibility can be exploited if the robot control system can be programmed easily. Anyway, it is quite obvious that a single robot cannot perform effective tasks in an industrial environment, unless it is provided with some additional equipment. For example, in building a component, two robots are required to cooperate, one holding some part while the other attaches some other part to it. In other tasks, robots may pursue different goals, making sure that they both don't attempt to use the same resource at the same time. Such synchronization and coordination can only be achieved by getting the robots to talk to each other or to some supervising agent. However, for large-scaled and complicated manufacturing systems, from the viewpoint of cost-performance and reliability appropriate representation and analysis methods of the control system have not sufficiently been established [1]. The lack of adequate programming tools for multiple robots make some tasks impossible to be performed. In other cases, since the control requirements are diversified and often changed, the cost of programming may be a significant fraction of the total cost of an application. Due to these reasons, the development of an effective programming method to integrate a system which includes various robots and other devices

**Implementation of Distributed** 

**Control Architecture for Multiple** 

**Robot Systems Using Petri Nets** 

Additional information is available at the end of the chapter

that cooperate in the same task is urgently required [2].

Gen'ichi Yasuda

**1. Introduction** 

http://dx.doi.org/10.5772/50577


**Chapter 4** 
