| Summary: | Managing consistency is a major concern in the design of complex engineering systems. At times, inconsistencies may lead to wrong decisions, resulting in design flaws which can compromise safety and cause failures. One cannot forget the 1999 NASA unmanned MARS Climate Orbiter, which was destroyed due to use of inconsistent units by design teams. Sadly, the history of inconsistency causing failures does not end there. In 2006 Airbus suffered a massive 6.1 billion dollar loss due to use of inconsistent specifications in different versions of design tools. So what causes inconsistency, and how best to avoid it? These are some of the critical questions behind the research reported in this thesis. Today's engineering systems cannot be designed by a single individual, but require the efforts of design teams each managing a portion of the overall problem. Naturally, information exchange between teams is necessary for effective decision making. However such communication is often error-prone and inadequate to manage dependencies between tasks, operations, components or properties. As a consequence, inconsistencies and design errors arise, which may cause catastrophic failures. This thesis investigates the nature of dependencies, typically in the design process of mechatronic products, and proposes an approach for model and dependency management. The proposed solution is based on an expressive Domain Specific Language which enables capturing dependencies (between disparate models) formally and explicitly. This language is called the Dependency Modeling Language (DML), and the supporting tool is named the Dependency Modeler. The overall approach is exemplified through a robot design example, where the DML is used to capture dependencies between mechanical design and control design models. In support of the DML, dependency patterns gather known dependency relationships between different types of properties - such as a pattern between system hierarchy and mechanical CAD assembly. Model transformations are essential to ...
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