Robust Design and Validation of Cyber-physical Systems

Abstract

Co-simulation--based validation of hardware controllers adjoined with plant models, with continuous dynamics, is an important step in model-based design of controllers for Cyber-physical Systems (CPS). Co-simulation suffers from many problems, such as timing delays, skew, race conditions, and so on, making it unsuitable for checking timing properties of CPS. In our approach to validation of controllers, synthesised from their models, the synthesised controller is adjoined with a synthesised hardware plant unit. The synthesised plant and controller are then executed synchronously and Metric Interval Temporal Logic (MITL) properties are validated on the closed-loop system. The clock period is chosen, using robustness estimates, such that all timing properties that hold on the controller guiding the discretised plant model also hold on the original case of the continuous-time plant model guided by the controller. Benchmark results show that real-time MITL properties that are vacuously satisfied or violated due to co-simulation artefacts hold correctly in the proposed closed-loop validation framework.