Matthias Hagner

Applying Model-based Software Product Line Testing Approaches to the Automation Engineering Domain

Abstract The software constitutes a major part of nowadays automation systems being responsible for conducting complex control tasks. Machines and plants are often unique in some industrial branches; hence, they become mechatronic products configured individually. The inherent software variability of those highly-configurable systems makes efficient, yet accurate quality assurance a challenging task. This article presents a comprehensive approach for applying model-based software product line testing techniques to the automation engineering domain. Existing approaches for variability modeling are adapted to domain specific modeling languages to allow for variability-aware test case generation and execution. The implementation of the approach is evaluated by means of a sample automation system product line.

UML-Based Analysis of Power Consumption for Real-Time Embedded Systems

The complexity of embedded systems has risen significantly in the last years. The model based development approach helped to keep an overview over the development and over the fulfillment of non-functional properties, as it is possible to capture and analyze the scheduling using UML development models. Other aspects, e.g. the power consumption, are not considered in development models, modelling languages, and analysis support based on development models. The common approach is to measure the consumption at the end of the development, but there is no tool support for earlier phases analysis. We present a UML profile for power/energy consumption and a simple algorithm to analyze the power consumption based on an UML model extended with our profile. As more power awareness could result in losing real-time constraints, we consider both aspects, real-time scheduling and power awareness, and present a method to bring both non-functional properties and their analyses in context. Additionally, we present an approach to find a task configuration for a dynamic voltage scaling system that satisfies all real-time requirements, but is most power efficient.

Integration of scheduling analysis into UML based development processes through model transformation

The complexity of embedded systems and their safety requirements have risen significantly in recent years. Models and the model based development approach help to keep overview and control of the development. Nevertheless, a support for the analysis of non-functional requirements, e.g. the scheduling, based on development models and consequently the integration of these analysis technologies into a development process exists only sporadically. The problem is that the analysis tools use different metamodels than the development tools. Therefore, a remodeling of the system in the format of the analysis tool or a model transformation is necessary to be able to perform an analysis. Here, we introduce a scheduling analysis view as a part of the development model, which is a MARTE annotated UML model to describe a system from the scheduling behavior point of view. In addition, we present a transformation from this annotated UML model to the scheduling analysis tool SymTA/S and a treatment of the analysis results to integrate scheduling analysis into a development process. With our approach it is not necessary to remodel the system in an analysis tool to profit from the analysis and its results. Additionally, we illustrate our approach in a case study on a parallel robot controller.

A methodology for model-based development and automated verification of software for aerospace systems

Todays software for aerospace systems typically is very complex. This is due to the increasing number of features as well as the high demand for safety, reliability, and quality. This complexity also leads to significant higher software development costs. To handle the software complexity, a structured development process is necessary. Additionally, compliance with relevant standards for quality assurance is a mandatory concern. To assure high software quality, techniques for verification are necessary. Besides traditional techniques like testing, automated verification techniques like model checking become more popular. The latter examine the whole state space and, consequently, result in a full test coverage. Nevertheless, despite the obvious advantages, this technique is rarely yet used for the development of aerospace systems. In this paper, we propose a tool-supported methodology for the development and formal verification of safety-critical software in the aerospace domain. The methodology relies on the V-Model and defines a comprehensive work flow for model-based software development as well as automated verification in compliance to the European standard series ECSS-E-ST-40C. Furthermore, our methodology supports the generation and deployment of code. For tool support we use the tool SCADE Suite (Esterel Technology), an integrated design environment that covers all the requirements for our methodology. The SCADE Suite is well established in avionics and defense, rail transportation, energy and heavy equipment industries. For evaluation purposes, we apply our approach to an up-to-date case study of the TET-1 satellite bus. In particular, the attitude and orbit control software is considered. The behavioral models for the subsystem are developed, formally verified, and optimized.

Runtime Analysis and Adaptation of a Hard Real-Time Robotic Control System

The increasing complexity of technical systems often leads to problems when they are to be maintained, changed or extended. Nature inspired concepts like selfmanagement or self-organization have found their way into technical systems to overcome the complexity problems. In turn those systems exhibit beneficial self-* properties like self-optimization, self-healing or self-protection. This paper presents a software architecture for the control of parallel kinematic machines and its evolvement to a selfadaptive system that strives to optimize, protect and heal itself. A software engineering approach for the development of self-managing components is introduced that is supported by behavior validation in a specialized simulation environment. The first realization of a self-manager, responsible for the distribution of control components, is described in detail to show that self-management is feasible in robotic control. The self-manager uses formal analysis techniques during the runtime of the system to make sure it always conforms to its real-time requirements.

Model Based Quality Assurance for a Robotic Software Architecture

This paper describes a model-based quality assurance approach in the context of a software architecture for parallel kinematic machines (PKMs). Due to high velocities PKMs are safety critical and cause hard real-time requirements for the according control system. In a joint effort mechanical engineers, electrical engineers, and computer scientists designed a software architecture for the special requirements of PKMs.

Runtime Analysis of a Self-Adaptive Hard Real-Time Robotic Control System

This paper describes a software architecture for parallel kinematic machines and its evolvement to a self-adaptive system striving to optimize, protect and heal itself Self-* properties are provided by self-manager components that observe and manipulate their associated system parts. A development approach for the self-managers is outlined, as is a first realization of a self-manager responsible for the control core. This self-manager distributes control components during runtime and makes feasibility decisions based on a runtime schedulability analysis

Dynamic distribution of robot control components under hard realtime constraints - Modeling, experimental results and practical considerations

It can be seen in numerous applications that embedded systems take advantage of distributed execution of tasks. Such distribution is studied in the present article, which investigates the deployment of robot control architectures across multiple computers. Besides the patterns for deployment across multiple hosts, this article proposes to introduce aspects of self-management into robot control architectures. It is proposed to use graph partitioning algorithms to determine the distribution pattern (mapping of control tasks to CPU resources while minimizing bus communication load). The underlying model and the respective analysis guarantee that, after adaption of the distribution pattern, real-time properties are preserved and load is balanced. In this way, poor a priori assumptions about worst-case execution times are detected and corrected continuously during runtime. This is a considerable improvement in comparison to using only offline analysis of worst-case execution times.

A Methodology for Scheduling Analysis Based on UML Development Models

The complexity of embedded systems and their safety requirements have risen significantly in the last years. The model based development approach helps to handle the complexity. However, the support for analysis of non-functional properties based on developmentmodels, and consequently the integration of these analyses in a development process exist only sporadically, in particular concerning scheduling analysis. There is no methodology that covers all aspects of doing a scheduling analysis, including process steps concerning the questions, how to add necessary parameters to the UML model, how to separate between experimental decisions and design decisions, or how to handle different variants of a system. In this chapter, we describe a methodology that covers these aspects for an integration of scheduling analyses into a UML based development process. The methodology describes process steps that define how to create a UML model containing the timing aspects, how to parameterise it (e.g., by using external specialised tools), how to do an analysis, how to handle different variants of a model, and how to carry design decision based on analysis results over to the design model. The methodology specifies guidelines on how to integrate a scheduling analysis for systems using static priority scheduling policies in a development process. We present this methodology on a case study on a robotic control system.