Design and testing of an assistive hand exoskeleton with hybrid architecture

Robotic technologies find application in increasingly diverse and heterogeneous environments: among these, the Healthcare System stands out due to its importance to society. In 2022, the World Health Organization confirmed that the world population age is constantly increasing, and the same goes for chronic diseases, causing a growing number of people with disabilities. Therefore, research in Wearable Robotics for the Healthcare System focuses on developing devices to meet the continuing and increasing demand for assistance and rehabilitation treatment for use in daily life to support ordinary activities or be integrated with functional recovery processes. Among wearable robotic devices, hand exoskeletons are considered special tools that enable people with hand impairments to interact with the environment by restoring their functional capabilities. This is the context for the research presented in this thesis and carried out during the Ph.D. period. It was focused on developing a novel hand exoskeleton for assisting users in Activities of Daily Living to regain their independence and improve their quality of life. An in-depth literature analysis found wearability, portability, safety, comfort, lightness, small overall dimensions, dexterity, efficacy in Activities of Daily Living, sense-of-touch preservation, and affordability as the primary design requirements an assistive hand exoskeleton should meet. The novel hand exoskeleton presented in this thesis was designed to pursue such requirements. The mechanical design was carried out after a careful and thorough literature review. It is based on an innovative hybrid finger-handling mechanism that includes rigid and soft components to be effective in force transmission but keep the overall dimensions above the finger contained, enabling movements in confined spaces. The first developed module and the whole hand exoskeleton were evaluated through Range Of Motion and force tests. The results showed that the subject wearing the device could grasp, hold, and manipulate the proposed items but highlighted flaws in the interface between the hand and exoskeleton. At the same time, the need for a more in-depth analysis of the soft architecture emerged. Therefore, a model of the hybrid finger-handling mechanism was developed and preliminary simulated. The main contribution of this work is the development of a novel hand exoskeleton that meets most requirements for assistive purposes, whose results are promising and an excellent starting point for future developments.