Research On Reconfigurable Manufacturing Execution System For RFID-based Real-Time Monitoring

With the trend of economic globalization, traditional manufacturers characterizedby mechanization, automation and economies of scale are transformed into modernmanufacturers characterized by information technology, advanced manufacturing andadaptability to changes. To bridge the critical information gap between EnterpriseResource Planning (ERP) systems and device control systems, a ManufacturingExecution System (MES) requires the capability of real-time monitoring to response tothe "expected" production situations and exceptions, as well as requires the capability ofquickly reconfiguring to response to the "unexpected" requirement change of businesslogic. Therefore, a Reconfigurable Manufacturing Execution System Architecture(RMESA), composed of the dimension of module granularity and the dimension ofinformation granularity, is proposed to meet the reconfiguration requirement and themonitoring requirement of MESs.In the dimension of module granularity, a cross-grained module framework isproposed to build and reconfigure MES with higher efficiency, higher quality and lowercomplexity. Accordingly, a MES can be composed of six types of module: entitymodules that abstract data, service modules that abstract business logic, human-machineinteraction modules that abstract the participation of humans, business process modulesthat abstract process logic, domain modules that abstract functional organization andinterface modules that abstract communication with external systems. In addition, theorganization, the coupling and the design patterns of these modules are normalized;meta-language technology such as code generating, code reusing and code templatingare deployed; common module elements are being collected; and a reconfigurationrequirement analyzing method is also proposed.In the dimension of information granularity, an event processing framework, whichis based on complex event processing (CEP) technology and model-based diagnosis(MBD) technology is proposed to support RFID-based real-time monitoring.Accordingly, there are four types of event defined: tag-read event, simple event,complex event and state event, from the minimal granularity to the maximal granularity.The simple event processing module, based on the Application Level Events (ALE) standard, is designed to transform machine-generating tag-read events into simpleevents that represent the temporal and spatial status of objects. The complex eventprocessing module, based on the CEP technology, is designed to transform simpleevents into complex events that represent meaningful occurrences. The system statediagnosis module, based on the MBD technology, is designed to reason aboutcomponent states in real time by considering the component model, the internel logicalconstraints, complex events and simple events. State events that represent productionexceptions or important situation are finally generated. As well, a tree-decompositionbased, projected prime implicate generation algorithm is proposed to greatly improvethe reasoning performance by speeding up the knowledge compilation on thecomponent state logical model.RMESA and the implemented system RMES have been applied successfully tosome cases. They are being researched, developed and industrialized.