The OASys Framework

The setting of my PhD research is a long-term research project on autonomous systems (ASys), which addresses a universal technology for the development of all classes of autonomous systems, regardless of its particular application domain. Autonomous systems refer to systems capable of operating in a real-world environment without any form of external control for extended periods of time. The core strategy is to exploit cognitive control loops, using knowledge captured as different models, based on the ontology for autonomous systems (OASys) developed in this research.

An ontology is a formal, explicit specification of a shared conceptualisation, i.e., a machine-readable abstract model where relevant concepts and relationships are identified and explicitly defined by consensus in a group. Ontologies have been widely applied for software engineering. They have also been used as representational mechanisms based on a computational language, to clarify and share the domain knowledge.

OASys captures and exploits the concepts to support the description and the engineering process of any autonomous system, as a domain-ontology structured in two levels of abstraction, innerly organised into Subontologies and Packages. The METHONTOLOGY methodology has been used as design method, with a final implementation in UML.

The autonomous system´s description has been formalised in the ASys Ontology, divided into the System Subontology and the ASys Subontology. The System Subontology contains the elements to define any system, consisting of: the General Systems Package to characterise any system's structure and behaviour based on the General Systems Theory; the Mereology Package with taxonomies of the whole-part concepts and relationships; the Topology Package for topological connections. The ASys Subontology specialises the former concepts for autonomous systems: the Perception Package to describe the perceptive and sensing processes; the Knowledge Package to characterise the different kinds of knowledge used; the Thought Package with task-oriented processes concepts; the Action Package about the operations and performing actors, and the Device Package to detail the devices.

The autonomous system´s engineering process has been formalised in the ASys Engineering Ontology, structured in the System Engineering Subontology and the ASys Engineering Subontology. The System Engineering Subontology gathers the concepts related to an engineering process, based on different metamodels and specifications: the Requirement Package to specify system's requirements; the Perspective Package with viewpoints in a system development; the Engineering Process Package to describe an engineering development process; and the Model-Driven Package to conceptualise the model-driven engineering approach. The ASys Engineering Subontology contains the specialisation and additional ontological elements to describe an autonomous system's generic engineering process: the ASys Requirement Package to characterise process and system quality requirements; the ASys Perspective Package to design an autonomous system from different aspects; the ASys Engineering Process Package to describe a generic autonomous system engineering process.

OASys has been complemented with the development of the OASys-based methodology to exemplify the use of OASys in a generic autonomous system engineering process.

The OASys Framework (ontology + methodology) has been applied in the Robot Control Testbed (RCT), and the Process Control Testbed (PCT). RCT is a collection of mobile robot systems, with a wide range of implementations and capabilities (from conventional SLAM based mobile robots to virtual ones inspired in rat brain neuroscience). PCT involves the development of a robust control architecture for a chemical reaction system (with multiple steady states), providing the system with cognitive capabilities to carry out complex tasks such as fault diagnosis, alarm management, and control system reconfiguration.