Modular exoskeleton design: Requirement engineering with KAOS

Abstract

Wearable robots, such as exoskeletons, interact closely with the wearer. To this end, mechanical features are combined with control techniques to transparently follow human movements. Such expected behaviour depends on special project requirements, safety being the most critical one. According to the literature, the modular robot design approach provides flexible and yet robust solutions that meets stakeholder requirements. The semi-formal design approach has been exploited by the scientific community to specifically focus on requirements definition. In this perspective, Goal Oriented Requirement Engineering (GORE) has been used as a tool for different systems; however, it has been more widely adopted in software rather than in hardware engineering. In this paper, GORE is adopted, with the KAOS tool, to fully exploit the integrated design of a modular exoskeleton - an adaptive mechatronic system. The balance of requirements with user safety constraints are analysed to advance in the project initial steps. It is shown that, although requirement modelling requires of an initial effort from the designer regarding goals formulation, the proposed approach provides a more comprehensive system overview and documentation. Finally, the adoption of a semi-formal language justifies why a modular exoskeleton is a good choice when design at meeting stakeholder requirements and improving user experience.