The aim of this paper is to present a component-based approach for the design of transitic systems and their implementation on operational architecture. It considers a flow that applies from specifications to integration the same model. This model is obtai

Using the operative part view, it is possible to start theinstallation of modelled entities. Each part of the transiticsystem can be fit up. The choice of physical parts is veryeasy because all parameters are fixed and the characteristicsof the components (conveyors, elevators, consignments,sorters, etc.) to install are well known and unambiguous.

Using the control part view, it is possible to implement thecode on controllers. ISaGRAF enables to generate directlythe code that must be load on the controller. Control can beimplemented on standards Programmable Logic Controllers(PLC) or on dedicated controllers. We develop at theLESTER laboratory a dedicated controller called nano-controller. The advantages of a nano-controller are describedbellow:

- the nano-controller is smaller than a classic controller

and can be installed very close to the physical parts it hasto control (connections, time to transmit orders toactuators and to receive information from sensors arethen reduced),

- many nano-controllers can be used to execute very

quickly the control of each low level components and amore global standard PLC can be used to execute thehierarchical control in a distributed manner,

- a nano-controller can be dedicated to specific control

tasks,

- a nano-controller is synthesised considering the

partitioning problem: several control tasks can beimplemented in software and others in hardware,

- a nano-controller is synthesised taking into account the

control task it has to execute and the operationalcomponent it has to control. Therefore, it is possible toanticipate the memory size, the number of I/O, theprocessor speed, etc.

Actually, the operational architecture for the nano-controller is composed of a NIOS Processor (it is aconfigurable RISC Processor) and a dedicated module forlow level communication by means of ASI-bus (ActuatorsSensors Interface bus). This dedicated module is describedusing VHDL (Very high speed integrated circuits HardwareDescription Language) and is synthesised on a FPGA (FieldProgrammable Gate Array). The control code is executedmainly by the NIOS Processor (software part) and somespecific treatments are implemented on the FPGA (hardwarepart). The nano-controller can be seen as an embeddedsystem or SOC (System On Chip) [9] dedicated to specificcontrol tasks described by the control part view of thecomponents.

VI. CONCLUSION

The aim of the presented method is to propose acomponent-based model of a transitic system and to validatethis system conjointly with its prototyping. On the basis ofthe obtained model, the prototyping step enables choice ofphysical parameters and control elaboration. The validationstep is based on simulation and a more formal approachbased on constraints satisfaction. The degradation risk duringthe on-site test is then reduced and the method enables to test

different possible solutions. The model is then implementedon the operational architecture. Parts of the transitic systemhave to be put together on the workshop and controls have tobe implemented on controllers (classical PLC or dedicatednano-controllers).

Further works would improve the component model byadding an other view stored in the library: the monitoringview. Monitoring view analyses whether the system followsthe specifications, from both operating part and control partlevel. During an integration phase, it would be synthesised onthe nano-controller in order to implement a reconfigurationprocess. We study also an other architecture to co-ordinatethe distributed components: the heterarchical one. The multi-agent paradigm could be used to model the entities with amore sophisticated control part view allowing the system tobe automatically reconfigured when disturbances appears.

VII. REFERENCES

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