Safe-guarded multi-agent control for mechatronic systems: implementation framework and design patterns

This thesis addresses two issues: (i) developing an implementation framework for Multi-Agent Control Systems (MACS); and (ii) developing a pattern-based safe-guarded MACS design method.\ud \ud The Multi-Agent Controller Implementation Framework (MACIF), developed by Van Breemen (2001), is selected as the starting point because of its capability to produce MACS for solving complex control problems with two useful features:\ud • MACS is hierarchically structured in terms of a coordinated group of elementary and/or composite controller-agents;\ud • MACS has an open architecture such that controller-agents can be added, modified or removed without redesigning and/or reprogramming the remaining part of the MACS

A PVS-Simulink Integrated Environment for Model-Based Analysis of Cyber-Physical Systems

This paper presents a methodology, with supporting tool, for formal modeling and analysis of software components in cyber-physical systems. Using our approach, developers can integrate a simulation of logic-based specifications of software components and Simulink models of continuous processes. The integrated simulation is useful to validate the characteristics of discrete system components early in the development process. The same logic-based specifications can also be formally verified using the Prototype Verification System (PVS), to gain additional confidence that the software design complies with specific safety requirements. Modeling patterns are defined for generating the logic-based specifications from the more familiar automata-based formalism. The ultimate aim of this work is to facilitate the introduction of formal verification technologies in the software development process of cyber-physical systems, which typically requires the integrated use of different formalisms and tools. A case study from the medical domain is used to illustrate the approach. A PVS model of a pacemaker is interfaced with a Simulink model of the human heart. The overall cyber-physical system is co-simulated to validate design requirements through exploration of relevant test scenarios. Formal verification with the PVS theorem prover is demonstrated for the pacemaker model for specific safety aspects of the pacemaker design

Conservative and traceable executions of heterogeneous model management workflows

One challenge of developing large scale systems is knowing how artefacts are interrelated across tools and languages, especially when traceability is mandated e.g., by certifying authorities. Another challenge is the interoperability of all required tools to allow the software to be built, tested, and deployed efficiently as it evolves. Build systems have grown in popularity as they facilitate these activities. To cope with the complexities of the development process, engineers can adopt model-driven practices that allow them to raise the system abstraction level by modelling its domain, therefore, reducing the accidental complexity that comes from e.g., writing boilerplate code. However, model-driven practices come with challenges such as integrating heterogeneous model management tasks e.g., validation, and modelling technologies e.g., Simulink (a proprietary modelling environment for dynamic systems). While there are tools that support the execution of model-driven workflows, some support only specific modelling technologies, lack the generation of traceability information, or do not offer the cutting-edge features of build systems like conservative executions i.e., where only tasks affected by changes to resources are executed. In this work we propose ModelFlow, a workflow language and interpreter able to specify and execute model management workflows conservatively and produce traceability information as a side product. In addition, ModelFlow reduces the overhead of model loading and disposal operations by allowing model management tasks to share already loaded models during the workflow execution. Our evaluation shows that ModelFlow can perform conservative executions which can improve the performance times in some scenarios. ModelFlow is designed to support the execution of model management tasks targeting various modelling frameworks and can be used in conjunction with models from heterogeneous technologies. In addition to EMF models, ModelFlow can also handle Simulink models through a driver developed in the context of this thesis which was used to support one case study

Efficient development of complex statecharts

Modeling systems based on graphical formalisms, such as Statecharts, has become standard practice in the design of embedded devices. Using paradigms established so far often results in complex models that are difficult to comprehend and maintain. To overcome this, we present a methodology to support the easy development and understanding of complex Statecharts. Central to our approach is the use of secondary notations to aid readability. We employ an automated layout mechanism to transform any given Statechart to a Statechart Normal Form. The Kiel Integrated Environment for Layout is a prototypical modeling tool to explore our editing, browsing and simulation paradigms in the design of complex reactive systems. An empirical study on the usability and practicability of our Statechart editing techniques, including a Statechart layout comparison, indicates significant performance improvements in terms of editing speed and model comprehension compared to traditional modeling approaches