Valid (Re-)Use of Models-of-the-Physics in Cyber-Physical Systems Using Validity Frames

Modelling and Simulation techniques play a key role in the design of Software-Intensive and Cyber-Physical Systems. They enable not only early virtual integration of the different parts of the system but also the use of the dynamic behavior of the physical system in the control algorithms, to cope with the continuous demand for improved system control and performance. These physics-based high-fidelity models are mostly numerically-intensive that cannot be deployed on restricted embedded targets without altering the model. Altering these high-fidelity models, e.g. by performing mathematical reductions, decreases the model(re-)usability if the range-of-validity of this model is not formally captured. In this paper, we report on a framework to formally capture the range-of-validity of models-of-the-physics. The needed meta-information to grasp the range-of-validity is captured within a Validity Frame, together with the necessary experimenting and selection methods to increase re-use of physics-based system models. An academic case study is performed to demonstrate the proposed methodology.

1 Introduction

Development of software intensive systems, found for example in the avionics and automotive domains, are becoming increasingly more complex. One of the causes of this complexity is the synergistically interaction between software and physical elements (Lee 2008). Another cause is the demand for performance improvement (EMPHYSIS 2018) of these systems to enable e.g. faster and safer control, autonomous driving, reduced energy consumption and emission, etc. This can be achieved by using a model of the physics of the system to be controlled or monitored. These physics-based models enable predicting the behavior of the system in its valid operating region which can be utilized in advanced control or observers/virtual sensors, achieving significantly optimized control and/or system monitoring (Sánchez et al. 2017, Zeyu et al. 2017).