DISCRETE EVENT SIMULATION-BASED ON REAL-TIME SHOP FLOOR CONTROL

1. DISCRETE EVENT SIMULATION-BASED ON REAL-TIME SHOP FLOOR CONTROL 21st European Conference on Modelling and Simulation (ECMS) June 4th - 6th, 2007, Prague / Czech Republic Presenter: Franck FONTANILI Authors: Samieh MIRDAMADI, Franck FONTANILI and Lionel DUPONT Department of Industrial Engineering/Ecole des Mines d’Albi-Carmaux/France

2. Summary • Shop Floor Control [SFC] • Discrete Event Simulation [DES]-based on SFC • Manufacturing Execution System [MES] for SFC • Requirements evolvement into on-line simulation • Experimentation Plate-Form and Out-Line

3. Orders Information Constraints Objectives Production Control Information Flow Court or middle Term Tactic • Shop order status info. • Real time data info. • Resources efficiency • WIP quantity information • … F.O. Launching • Shop order priority • Planned decision • … F.O. Reporting SFC (Order / Monitoring) Consign Actions Information feedback Real Time Operational Operation System Row material Goods a. SFC definition & its sub-functions b. A classification of SFC c. Control tools to aid decision-making d. Problematic of SFC • Shop Floor Control [SFC] All the activities of short-term production in agreement with the objectives established by the production control, by adapting the production to the disturbances which can occur on the level of the workshop. [APICS,05], [Grabot,97]

4. Experience feedback Predictive Control To Preparation Estimated data Unforeseen events and critical drift of system variables (e.g. cycle time) Very weak probability of events occurrence Proactive Control To Anticipation Reactive Control To Correction Experience feedback a. SFC definition & Its sub-functions b. A classification of SFC c. Control tools to aid decision-making d. Problematic of SFC • Shop Floor Control [SFC] Exploitation Off-Line Control On-Line Control System in the course of execution Existing System Before Execution Temporal axis

5. DES Tools for Discrete Events Simulation of flows To Design To Improve To Control a. SFC definition & Its sub-functions b. A classification of SFC c. Control tools to aid decision-making d. Problematic of SFC • Shop Floor Control [SFC] Product life cycle Conception Re-engineering Exploitation CAD, CAM, CAE (DESIGN, MANUFACTURING, ENGINEERING) CAPM, ERP Scheduling MIS, MES, CIM, CAIT Supervision Order / Monitoring (API) CAPE (PRODUCTION ENGINEERING) Specific to the Production Systems MES  Manufacturing Execution System (often coupled with the supervision)

6. DES Allows to anticipate in the future but does not allow to direct connection to a real system in the course of execution MES Brings a lot of information allowing to make decisions but does not allow to make sure that they are the good decisions. Use On-Line Discrete Events Simulation for the decision-making aid in Reactive and Proactive Control of workshop by coupling withMES a. SFC definition & Its sub-functions b. A classification of SFC c. Control tools to aid decision-making d. Problematic of SFC • Shop Floor Control [SFC]

7. E.g.. Scheduling, to manage the capacity of the queues… • Determinist or strong probability of appearance (cycle time…) • Off-Line Simulation Application (non direct connection) • E.g. Machine breakdown (unforeseen but known)… • Very weak probability of occurrence • Off-Line Simulation Application (non direct connection) Objectives Predictive Control • E.g. Cycle time Drifts of a machine (unforeseen and unknown)… • To minimize the drifts compared to the deadlines envisaged • On-Line Simulation Application (direct connection) Proactive Control Reactive Control • DES-based on SFC a. SED Application in production b. Different use of simulation

8. Predictive Control Process Off-Line Simulation Measure Decision Validation Reactive Control Process Monitoring Filtering Evaluation On-Line Simulation Optimization Correction Proactive Control Process Identification Off-Line Simulation Optimization Validation Stocking • DES-based on SFC a. SED Application in production b. Different use of simulation

9. MES for real time Shop Floor Control Information Decision • Executes the commands (orders) of the production control. •  Delivers relevant information on the follow-up and the realization of the shop orders in real time. APS Strategic Management I.S. Differed Time ERP MES Tactic Supervision Real Time Order / Monitoring Fabrication I.S. Operational Fabrication process

10. Requirements evolvement into On-Line Simulation Validation of the simulation model On-Line connection Data usable: Availability and Correctness of the data Data Acquisition Classification and events analyzes Initialization of the model Response time (Speed of the simulator) Correction of the parameters in real time

11. II. On-Line connection MES Simulation Model OPC Data Base Supervision Ethernet networks of the real system API API API … • Requirements evolvement into On-Line Simulation I. Validation of the simulation model • Connect the model to the expected or received reality • Relevance of the model: sufficient quality • Completed of the model: all the necessary information • Establish the fidelity of the simulation model • Produce a definitive proof to support the model • Reduce the risk

12. IV. Data Acquisition • Use of a data base of workshop • Methods of Acquisition: • Sensors: measure by Detector • DBMS: Information system III. Data usable: Availability and Correctness of the data Data usable Availability Correctness complete Incomplete Errors Up to dateness  Way to collect Measure Application • Requirements evolvement into On-Line Simulation

13. VI. Initialization of the model • The real system must be planned from the current state of the system. • To start with, a “not-empty” state of the model corresponding at the real state. • Requirements evolvement into On-Line Simulation V. Classification and events analyzes Events Unforeseen Foreseen On-Line appearances Unknown Known Strong Probability with lapse of time Weak Probability Unknown probability

14. Simulation time t1 t1+ t Real Time t VIII. Correction of the parameters in real time • To transfer and execute the best realizable solution from simulation towards MES • Requirements evolvement into On-Line Simulation VII. Response time (Speed of the simulator) • Reasonable response time between decision-making and control execution • t depends on the characteristics of the workshop

15. Operational System Information System Ethernet networks of the real system D.B. M.E.S Networks Sensor Actuators OPC Server Histories data OPC Client  Loading API Unloading API Operation API Transfer API Simulation Model (SIMBA) • Experimentation Plate-Form and Out-Line Real Time Data

16. Experimentation Plate-Form and Out-Line •  Experimentation of reactive control on the Technology plat-form • Collect data of the ground by MES • Filtering of the events releases • Initialization of the simulation model by injection of the collected data • Possibilities of application to a logistic chain • Performance analyze

17. Thank you for your attention

18. Shop orders To realize Off-Line Simulation Results analysis Predictive Control Before Execution yes Validation Achieved objective? No Optimization of the Control parameters Launch of the execution of the shop orders on the real system Reactive Control During Execution ? Realized Shop orders DES-based on SFC a. Off-Line Simulation process b. On-Line Simulation process How will it take place during the execution in case of appearance of an unforeseen event…?

19. Predictive Control Proactive Control Application of the proactive control result Realize the estimated parameters by predictive control Case Base Shop orders execution In progress Reactive Control During Execution Classification of the unforeseen events Monitoring of the real system state Yes Known events? No Filtering the events to release simulator Scenarios of Real-time Simulation The current state of the system No Events release ? Correction of the control parameters on the model Yes Initialization of the simulation model yes Variation on objective? Activate the On-Line Simulation No Realizable decision-making in real time Validation (Without modification) Achieved objective? Yes Correction of the control parameters on the real system No DES-based on SFC a. Off-Line Simulation process b. On-Line Simulation process

20. DES-based on SFC a. Off-Line Simulation process b. On-Line Simulation process Shop orders To realize Estimate the most frequent disturbances Diverse scenarios of Off-Line Simulation Off-Line Simulation Pooling Validation Prepare the relevant solutions Results analysis Predictive Control Before Execution Proactive Control Before execution yes No No Achieved objective? Case Base Results of Proactive Simulations Optimization of the Control parameters Yes Launch of the execution of the shop orders on the real system Reactive Control During Execution Realized Shop orders