A co-simulation approach for system-level analysis of embedded control systems

Control applications have become an integral part of modern networked embedded systems. However, there often exists a gap between control engineering and system design. The control engineer has detailed knowledge about the algorithms but is abstracting from the system architecture and implementation. On the other hand, the system designer aims at achieving high-quality implementations based on quality constraints specified by the control engineer. This may result in either an overdesigned system in case the specifications are pessimistic or an unsafe system behavior when specifications are too optimistic. Thus, future design automation approaches have to consider the quality of control applications both as design objectives and design constraints to achieve safe yet highly optimized system implementations. The work at hand introduces an automatic tool flow at the Electronic System Level (ESL) that enables the optimization of a system implementation with quality of control being introduced as a principal design objective, like the maximum braking distance, while respecting constraints like maximum slip to ensure maneuverability of a car. The gap between mathematically well-defined models for system synthesis and common analysis techniques for control quality is bridged by co-simulation: A SystemC-based virtual prototype of a distributed controller implementation is combined with high-level models of the plants specified in Matlab/Simulink. Through a model transformation, the traditional development process of control applications is combined with state-of-the-art ESL techniques, ensuring model consistency while enabling a high degree of automation.