F.L. Lewis, Assoc. Director for Research Moncrief-O’Donnell Endowed Chair Head, Controls, Sensors, MEMS Group Automation & Robotics Research Institute (ARRI) The University of Texas at Arlington Wireless Sensor Networks for Monitoring Machinery, Human Biofunctions, and BCW Agents Sponsored by IEEE Singapore SMC, R&A, and Control Chapters Organized and invited by Professor Sam Ge, NUS

Automation & Robotics Research Institute (ARRI) The University of Texas at Arlington F.L. Lewis, Assoc. Director for Research Moncrief-O’Donnell Endowed Chair Head, Controls, Sensors, MEMS Group Discrete Event Control & Decision-Making

Discrete Event Control Objective: Develop new DE control algorithms for decision-making, supervision, & resource assignment WITH PROOFS Apply to manufacturing workcell control, battlefield C&C systems, & internetworked systems Patent on Discrete Event Supervisory Controller New DE Control Algorithms based on Matrices Complete Dynamic Description for DE Systems Formal Deadlock Avoidance Techniques Implemented on Intelligent Robotic Workcell Internet- Remote Site Control and Monitoring USA/Mexico Collaboration Exploring Applications to Battlefield Systems $75K in ARO Funding for Networked Robot Workcell Control $80K in NSF Funding for research and USA/Mexico Network USA/Mexico Internetworked Control Man/Machine User Interface Intelligent Robot Workcell Dr. Jose Mireles- co-PI

DE Model State Equation: Where multiply = AND & addition = OR whereis the task or state logic is the job sequencing matrix (Steward) is the resource requirements matrix (Kusiak) is the input matrix is the conflict resolution matrix Matrix Formulation: Definition Based on Manufacturing Bill of Materials Job Start Equation: Resource Release Equation: Product Output Equation:

Meaning of Matrices Resources required Prerequisite jobs Next job Next job FvFv FrFr Conditions fulfilled Next job SvSv Release resource SrSr Steward’s Task Sequencing MatrixKusiak’s Resource Requirements Matrix Bill of Materials (BOM) Conditions fulfilled

ARRI Intelligent Material Handling (IMH) Cell 3 robots, 3 conveyors, two part paths EXAMPLE

Layout of the IMH Cell

Construct Job Sequencing Matrix F v Part A job 1 Part A job 2 Part A job 3 Part B job 1 Part B job 2 Part B job 3 Part A job 1 Part B job 1 Part A job 2 Part B job 2 Part A job 3 Part B job 3 Next jobs Prerequisite jobs Used by Steward in Manufacturing Task Sequencing Contains same information as the Bill of Materials (BOM)

Construct Resource Requirements Matrix F r Used by Kusiak in Manufacturing Resource Assignment Contains information about factory resources Next jobs Prerequisite resources Part A job 1 Part A job 2 Part A job 3 Part B job 1 Part B job 2 Part B job 3 Conveyor 1 Conveyor 3 Fixture 1 Robot 1- IBM Robot 2- Puma Robot 3- Adept

More About F v J2 J5 J6 J1 J3 J4 Two 1’s in same col. = Routing (Job Shop) Two 1’s in same row = Assembly J3 J4 J5 J1 J2 J6 More About F r J2 J5 J6 R1 R2 R3 Two 1’s in same col. = Shared Resource Two 1’s in same row = Job needs multiple res. J5 R2 R3 R1 J2 J6 DECISION NEEDED! DECISION NEEDED!

Controller based on Matrix Formulation Workcell Matrix Formulation Discrete Event Controller External events present Jobs completed Resources released Tasks completed External Events Start jobs Start resource release Task complete Dispatching rules Resource allocation, task planning, task decomposition, Bill of Materials

Formal rigorous framework Complete DE dynamical description Relation to known Manufacturing notions Formal relation to other tools- Petri Nets, MAX-Plus Easy to design, change, debug, and test Formal deadlock analysis technique Easy to apply any conflict resolution (dispatching) strategy Optimization of resources Easy to implement in any platform (MATLAB, LabVIEW, C, C++, visual basic, or any other) Advantages of the Matrix Formulation

Relation to Petri Nets Resources availableJobs complete Trans. Fv Fr Transition Next jobs Sv Transition Release resource Sr

p inA p1p1 t1t1 t2t2 p3p3 t4t4 t5t5 p2p2 t3t3 p4p4 t6t6 p inB p outA p outB r1r1 r3r3 r2r2 p 1 p 2 p 3 p 4 r 1 r 2 r 3 p 1 p 2 p 3 p 4 r 1 r 2 r 3 p inA p inB p outA p outB Example t1t2t3t4t5t6t1t2t3t4t5t6 t1t2t3t4t5t6t1t2t3t4t5t6

p inA p1p1 t1t1 t2t2 p3p3 t4t4 t5t5 p2p2 t3t3 p4p4 t6t6 p inB p outA p outB r1r1 r3r3 r2r2 FvFv OR/AND Algebra- Locating transitions firing from current marking FrFr FuFu =, so x = v r u x = i.e. fire t 2 and t 4

Activity Completion Matrix F: Activity Start Matrix S: Complete DE Dynamic Formulation PN Incidence Matrix: PN marking transition equation: Allowable marking vector:

Petri Net Marking Transition Equation-- need to add Job Duration Times PN Marking Vector Split transition equation in two steps Add tokens Subtract tokens when job complete Add Time Duration Vector Corresponds to Timed Places

Allows Direct Simulations- e.g. MATLAB Jobs completed by Robot 1 Robot 1 busy or idle c.f. DE version of ODE23

p inA p1p1 t1t1 t2t2 p3p3 t4t4 t5t5 p2p2 t3t3 p4p4 t6t6 p inB p outA p outB r1r1 r3r3 r2r2 FvFv Conflict Resolution for Shared Resources FrFr FuFu =, so x = v r u Which one to fire? But gives negative marking! Cannot fire both. Shared Resource- Two entries in same column

p inA p1p1 t1t1 t2t2 p3p3 t4t4 t5t5 p2p2 t3t3 p4p4 t6t6 p inB p outA p outB r1r1 r3r3 r2r2 FvFv Conflict resolution, add extra CR input and new matrix F uc : FrFr FuFu =, so x = v r u F uc r2r2 Now only t 5 fires r2r2

Application- Intelligent Material Handling Adept Puma CRS 12 Sensors!! Machine 2 Machine 1

ARRI Intelligent Material Handling (IMH) Cell 3 robots, 3 conveyors, two part paths

Layout of the IMH Cell

Multipart Reentrant Flow Line c.f. Kumar

Petri Net flow chart

c.f. Saridis Jim Albus

LabVIEW diagram of Controller

LabVIEW Controller's interface: FrFr FvFv Resources

R1u1 R1u2 R1u3 R1u4 R2u1 R2u2 R2u3 R3u1 R3u2 Discrete events Results of LabVIEW Implementation on Actual Workcell Compare with MATLAB simulation! We can now simulate a DE controller and then implement it, Exactly as for continuous state controllers!!

U.S.-Mexico shared research DE control via internet Using Matrix DEC in LabVIEW Texas