A systematic approach to model-based engineering of cyber-physical systems of systems

Abstract

This thesis describes and evaluates methods for the model-based engineering of Systems of Systems (SoSs) where constituents comprise both computational and physical elements typical of Cyber-Physical Systems (CPSs). Such Cyber-Physical Systems of Systems (CPSoSs) use sensors and actuators to link the digital and physical worlds, and are composed of operationally and managerially independent constituent systems that interact to deliver an emerging service on which reliance is placed. The engineering of CPSoSs requires a combination of techniques associated with both CPS engineering and SoS engineering. Model-based SoS engineering techniques address organisation and integration of diverse systems through the use of disciplined architectural frameworks and contractual modelling approaches. Advances in model-based CPS engineering address the additional challenges of integrating semantically heterogeneous models of discrete and continuous phenomena. This thesis combines these approaches to develop a coherent framework for the model-based engineering of CPSoSs. The proposed approach utilises architectural frameworks to aid in the development of rich abstract models of CPSoSs. This is accompanied by the specification of an automated transformation process to generate heterogeneous co-models based on the architectural description. Verification of the proposed engineering approach is undertaken by its application to a case study describing the control of trains over a section of rail network, in which the (cyber) behaviour of control infrastructure must be considered in conjunction with the (physical) dynamics of train movements. Using the proposed methods, the development of this CPSoS uses architectural descriptions to generate an executable model to enable the analysis of safety and efficiency implications of the implemented control logic. The utility of the approach is evaluated by consideration of the impact of the proposed techniques on advancing the suitability and maturity of baseline technologies for the engineering of CPSoS. It is concluded that the proposed architectural framework provides effective guidance for the production of rich architectural descriptions of CPSoSs, and that the conversion between architectural and executable models is viable for implementation in a suitable open tools framework.