Automotive Electronic/Electric Architecture Modeling, Design Exploration and Optimization using Clafer

Abstract

Modern car systems are getting more complex, so do car electronic/electric (E/E) architectures. E/E architecture of a car includes sensors, actuators, programmable ECUs and all the related communications. The complexity of E/E architectures increases dramatically: modern car have more than 100 of ECUs and communications spread over the entire vehicle. Therefore, the development of such architectures is a major challenge. Additional complexity comes from cross-cutting concerns, such as, variability and dependability.

To manage this complexity and reduce costs, architects and engineers apply model-based methods to automate analysis, perform simulation, and make key decisions before the actual implementation. To quantify the analysis results, engineers use quality attributes, such as, cost, power consumption, complexity, maintainability, and wire length. Introduction of quality attributes also allows engineers to perform architecture optimization.

In this work, we explore applicability of a modeling language called Clafer to address E/E architecture modeling, exploration and optimization problems. Clafer is a general-purpose domain-modeling language that comes with tools and solvers that are capable of performing consistency checking, design exploration and optimization. Clafer has minimalistic syntax, but its first-order logic based semantics is rich enough to represent a wide range of domains.

Our main contributions include: formulation of Clafer domain modeling principles with respect to architecture modeling, identification of Clafer design patterns in general, and demonstration of applicability of Clafer to architecture exploration and optimization. To evaluate our approach, we develop the Power Window case study. The Power Window system's E/E architecture is a rich representative of a car E/E architecture: it can be decomposed into subsystems, it can have smart or dumb sensor and actuators, and it requires wire or bus communications within and across subsystems. We consider the following topics: representing Power Window system's features and functions, automated hardware topology generation, and automated deployment of functions to hardware.

Our case case study concludes that Clafer is capable of representing all structural aspects of E/E architectures: from modeling a device to modeling an entire system. Clafer tools can facilitate automated deployment and hardware topology generation and perform architecture multi-objective optimization within a reasonable time. And finally, Clafer language features, such as arbitrary property nesting, result in clear, concise and lightweight structural models.