Reconfigurable Embedded Control Systems

Abstract

The chapter deals with distributed multi-agent reconfigurable embedded control systems following the component-based International Industrial Standard IEC61499 in which a Function Block (abbreviated by FB) is an event-triggered software component owning data and a control application is a distributed network of Function Blocks that have classically to satisfy functional and to meet temporal properties described in user requirements. The authors define a new reconfiguration semantic where a crucial criterion to consider is the automatic improvement of the system’s performance at run-time, in addition to its protection when hardware faults occur. To handle all possible cases in industry, the authors classify thereafter the reconfiguration scenarios into three forms before the authors define an architecture of reconfigurable multi-agent systems where a Reconfiguration Agent is affected to each device of the execution environment to apply local reconfigurations, and a Coordination Agent is proposed for any coordination between devices in order to guarantee safe and adequate distributed reconfigurations. A Communication Protocol is proposed in our research work to handle coordinations between agents by using well-defined Coordination Matrices. The authors specify both the reconfiguration agents to be modelled by nested state machines, and the Coordination Agent according to the formalism Net Condition/Event Systems (Abbreviated by NCES) which is an extension of Petri nets. To verify the whole architecture, the author check by applying the model checker SESA in each device functional and temporal properties described in the temporal logic “Computation Tree Logic”, but the authors have also to check any coordination between devices by verifying that whenever a reconfiguration is applied in a device, the Coordination Agent and other concerned devices should react as described in user requirements. The chapter’s contributions are applied to two Benchmark Production Systems available in our research laboratory.