Technology Lecture: A Matrix Framework for Discrete Event Control of Manufacturing Systems and Sensor Networks

Date: 19 Jun 2008 - 19 Jun 2008

Venue: SIMTech Training Room, Level 3, Tower Block

A new matrix framework for the design and analysis of discrete event (DE) supervisory controllers has been developed at The University of Texas at Arlington.  A U.S. Patent has been received on this novel formulation.  It has been discovered that any machine-generated plan can be represented in terms of four matrices -- two for job sequencing and two for resource assignment. Given these four Task Plan Matrices, it is straightforward to configure a rule-based DE controller that can sequence the jobs and assign shared resources dynamically in real-time. The job sequencing matrices contain information like that in the Bill of Materials and assembly tree.  The second pair of matrices contains information like that in the resource requirements matrix.  The discrete event matrix controller plus the Petri net transition equation together provide a complete dynamical description for DE systems.  This makes it straightforward to simulate DE systems using software such as MATLAB in a similar fashion to standard ODE integrators for the simulation of continuous-state systems.

It is pertinent to note that deadlock is a condition where operation of an FMS is indefinitely delayed and production halted;  it can occur if incorrect dispatching is performed for assigning shared resources.  Rigorous matrix techniques are given for analysing the circular wait structure of the FMS.  In terms of certain associated 'critical siphons', techniques are given for shared resource dispatching that are guaranteed to avoid deadlock.  To avoid deadlock, the Work in Process is limited in certain 'critical subsystems'.  This MAXWIP technique amounts to a generalised kanban sort of feedback control that offers the best performance possible while avoiding deadlock. Applications are given for robot workcell control and supervisory control of mobile wireless sensor networks. 

This programme is coorganised by :
IEEE IE Chapter Singapore
IEEE IES Technical Committee on IMSS

About the Speaker
Born in Würzburg, Germany, Professor Lewis received his Bachelor's Degree in Physics/Electrical Engineering and the Master of Electrical Engineering Degree from Rice University in 1971.  He spent six years in the U.S. Navy, serving as Navigator aboard the frigate USS Trippe (FF-1075), and Executive Officer and Acting Commanding Officer aboard USS Salinan (ATF-161).  In 1977 he received the Master of Science degree in Aeronautical Engineering from the University of West Florida.  In 1981 he obtained the Doctorate degree at The Georgia Institute of Technology in Atlanta, where he was employed as a professor from 1981 to 1990 and is currently an Adjunct Professor.

He was awarded the Moncrief-O'Donnell Endowed Chair in 1990 at the Automation & Robotics Research Institute, University of Texas at Arlington and he is a Fellow of the IEEE, Fellow of IFAC, Fellow of the UK Institute of Measurement & Control, Member of the New York Academy of Sciences.  Registered Professional Engineer in the State of Texas and Chartered Engineer, U.K. Engineering Council. He is Charter Member (2004) of the UTA Academy of Distinguished Scholars and Senior Research Fellow of the Automation & Robotics Research Institute.  Has served as Visiting Professor at Democritus University in Greece, Hong Kong University of Science and Technology, Chinese University of Hong Kong, National University of Singapore.  Elected Guest Consulting Professor at both Shanghai Jiao Tong University and South China University of Technology. 

His current interests include intelligent control, neural and fuzzy systems, wireless sensor networks, nonlinear systems, robotics, condition-based maintenance, micro-electro-mechanical systems (MEMS) control, and manufacturing process control. He is author of 5 U.S. patents and has published 184 journal papers, 34 chapters and encyclopedia articles, 306 refereed conference papers, and 12 books, including Optimal Control, Optimal Estimation, Applied Optimal Control and Estimation, Aircraft Control and Simulation, Control of Robot Manipulators, Neural Network Control, High-Level Feedback Control with Neural Networks and the IEEE reprint volume Robot Control.  He is the Editor of Taylor & Francis Book Series on Automation & Control Engineering. He also serves on many Editorial Boards including International Journal of Control, Neural Computing and Applications, Optimal Control & Methods, and Int. J. Intelligent Control Systems. He was the Editor for the flagship journal Automatica.  Recipient of NSF Research Initiation Grant and continuously funded by NSF since 1982.

Since 1991 he has received $6 million in funding from NSF, ARO and other government agencies, including significant DoD SBIR and industry funding. His SBIR program was instrumental in ARRI’s receipt of the US SBA Tibbets Award in 1996.  Received Fulbright Research Award, American Society of Engineering Education F.E. Terman Award, three Sigma Xi Research Awards, UTA Halliburton Engineering Research Award, UTA Distinguished Research Award, ARRI Patent Awards, various Best Paper Awards, IEEE Control Systems Society Best Chapter Award (as Founding Chairman of DFW Chapter), and National Sigma Xi Award for Outstanding Chapter (as President of UTA Chapter).  He received numerous accolades including the outstanding Service Award from the Dallas IEEE Section and selected as Engineer of the year by Ft. Worth IEEE Section.  Listed in Ft. Worth Business Press Top 200 Leaders in Manufacturing.  Appointed to NAE Committee on Space Station in 1995 and IEEE Control Systems Society Board of Governors in 1996.  Selected in 1998 as an IEEE Control Systems Society Distinguished Lecturer.  Founding Member of the Board of Governors of the Mediterranean Control Association.

1.30pm  Registration 

 2.00pm  Introduction & Presentation               

 3.15pm  Q&A

 3.30pm  Refreshments & Networking 

 4.00pm  End

Who Should Attend
Industry professionals, R&D managers, researchers, engineers, professors and students.

Registration for the lecture is free of charge. Seats are available on a first-come, first-served basis. 

For technical enquiries, please contact
Dr Luo Ming, Research Scientist, Email:

For registration and general enquiries, please contact
Alice Koh, Email: