Bernd Hedenetz

Managing complexity and variability of a model-based embedded software product line

This paper presents a framework for model-based product lines of embedded systems. We show how to integrate model-based product line techniques into a consistent framework that can deal with large product lines as they are common in industry. The framework demonstrates the strengths of model-based techniques like abstraction, support for customised representations, and a high degree of automation. In particular, we provide the following contributions: (1) to shift existing product lines towards a model-based approach, we support the (semi-) automated extraction of models from existing requirement, test, and implementation artefacts; (2) to cope with the complexity of artefacts and their interrelations in industrial product lines, we support the generation of context-specific views. These views support developers, e.g., in analysing complex dependencies between different artefacts; (3) finally, we support automated product derivation based on an integrated hardware abstraction layer. Most of the presented concepts have been inspired by challenges arising in the industrial application of product line techniques in the model-based engineering of embedded systems. We report on experiences gathered during the application of the techniques to a prototypical product line (on a rapid prototyping platform in the university lab) and to industrial sample cases (at the industry partner).

Increasing System Safety for By-Wire Applications in Vehicles by Using a Time Triggered Architecture

By-wire systems have been established for several years in the area of aircraft construction and there are now approaches to utilize this technology in vehicles. The required electronic systems must evidently be available and safe. In the same time the requirements of mass production have to be reached (long life time, long maintainability intervals, low costs, fulfillment of standards). This paper addresses a new automotive architecture approach - based on a time triggered architecture - and a framework for the application design of future by-wire systems in vehicles.

Test front loading in early stages of automotive software development based on AUTOSAR

Embedded software development has become one of the greatest challenges in the automotive domain, due to the rising complexity of vehicle systems. A method to handle the complexity of automotive software is Model Based Design (MBD). As MBD offers great advantages in early simulation and testing, it has become todays mainstream method for automotive software engineering. However, some aspects can be initially tested after the integration of software on real hardware components (usually by the supplier) and when all parts of a system (e.g. bus systems, sensors, actuators) are present. The consequence is that the requirement specification of the according system possibly contains gaps that can lead to software defects. New technologies like the AUTOSAR standard enable additional potentials for the validation of model based developed software. Due to the AUTOSAR software architecture it is possible for an OEM to realize an early “virtual” software integration with an acceptable effort and perform at next step a front loading of system tests. In this paper we present an approach that improves the quality of the requirement specification artifacts by using test front loading. In detail, we analyze the requirement engineering part of the software development process to identify aspects that can not be tested without having all system components. Afterwards, we classify these aspects and define an abstract test pattern that can be globally used for testing. Additionally, we illustrate our approach in a case study on an interior light system for the next Mercedes-Benz M-Class generation.

A development framework for ultra-dependable automotive systems based on a time-triggered architecture

Today by-wire systems are well-known and utilised in the area of aircraft construction. In the last few years there has been an endeavour in the automotive industry to realise by-wire applications without mechanical or hydraulic backup systems in vehicles. The required electronic systems must be highly reliable and cost-effective due to the constraints of mass production. A time-triggered architecture is a new approach that satisfies these requirements. The backbone of communication in this architecture is the fault-tolerant Time-Triggered Protocol (TTP), developed by the Vienna University of Technology and the Daimler-Benz Research. The TTP protocol has been designed due to the class C SAE classification for safety critical control applications, like brake-by-wire or steer-by-wire. For time-triggered architectures a new development process is required to handle the complexity of the systems, accelerate the development and increase the reliability. In this paper we present an approach for the development of distributed fault-tolerant systems based on TTP. The present approach is evaluated by a brake-by-wire case study.

Variability management in the AUTOSAR-based development of applications for in-vehicle systems

In automotive electrical/electronics systems, reuse of software applications over vehicle lines is becoming essential due to the growing complexity of the applications. In addition, a growing number of variants have to be handled because of the increasing number of differences arising in vehicle lines. Software product lines are a common approach to address these issues. This paper presents the challenges and our vision for the introduction of a product line approach in the context of AUTOSAR (AUTomotive Open System Architecture)-based development of applications for in vehicle systems.

View-supported rollout and evolution of model-based ECU applications

When applying model-based techniques to the engineering of embedded application software, a typical challenge is the complexity of dependencies between application elements. In many situations, e.g., during rollout of products or in the evolution of product lines, the understanding of these dependencies is a key capability. In this paper, we discuss how model-based techniques, in particular, model transformations can help to reduce the complexity of such analysis tasks. To this end, we realised a representation of Simulink models based on the Eclipse Modeling Framework (EMF). The resulting integration allows us to apply various model-based frameworks from the Eclipse ecosystem. On this basis we developed a view that increases the visibility of functional dependencies, which otherwise would have been hidden due to a lack of abstraction in the native Simulink representation. The provided analysis framework comes in handy, when such a model has to be modified. Consequently, the developer is supported in reusing existing models and avoiding errors. The concepts and techniques are illustrated with a running example, which is derived from a real industry model from Automotive Software Engineering.

Virtual Integration of Model-Based Functions Under Autosar

As a result of the standardisation of the ECU software architecture by Autosar, there are new potentials in the early validation of vehicle functions. For the first time it is possible to integrate “virtually“ the E / E functions with a reasonable effort and to front load tests which up to now were carried out late in the development process. This article reports of current experiences at the virtual integration of model-based developed comfort and interior functions which were gained by Daimler AG in an advanced development project.

Assessing the Evolution of E/E Hardware Modules with Conceptual Function Architectures

Original Equipment Manufacturers (OEMs) use hardware module strategies to reduce hardware costs and development time. They prefer stable and cost efficient design concepts but the introduction of innovative functions requires agile methods. Therefore, it is still a challenge to transfer product features to the design of the E/E architecture in the context of a modularised E/E hardware. Hence, this paper presents a novel approach for the E/E architecture modelling using a conceptual function architecture layer as further abstraction to allow design decisions. The approach improves the transparent description of E/E systems in the E/E architecture development, the comprehension of the complex systems of modern premium cars, and the traceability from product features to E/E hardware.

Virtuelle Integration Modellbasierter Fahrzeugfunktionen unter Autosar

Aufgrund der Standardisierung der Steuergerate-Software-Architektur durch Autosar ergeben sich neue Potenziale bei der fruhzeitigen Absicherung von Fahrzeugfunktionen. Es ist erstmalig mit einem vertretbaren Aufwand moglich, die Elektrik/Elektronik-Funktionen „virtuell“ zu integrieren und Tests vorzuziehen, die bisher spat im Entwicklungsprozess erfolgten. Der vorliegende Artikel berichtet uber aktuelle Erfahrungen bei der virtuellen Integration von modellbasiert entwickelten Komfort- und Innenraumfunktionen, die in einem Vorentwicklungsprojekt bei der Daimler AG gewonnen wurden.