A preliminary synthesis of a light and compact wearable cable-driven parallel robot for wrist joint rehabilitation

Robot-assisted rehabilitation has proven to be effective in clinical practice, not only because of its ability to perform repetitive and intensive rehabilitation therapy but also because its rehabilitation outcome is not limited by the lack of experienced therapists or their fatigue due to long and repetitive rehabilitation sessions. Several robotic solutions have been proposed over time, but rarely have these solutions been successful, in particular due to the excessive bulk, discomfort, and joints alignment of the robotic solution. This paper lays the foundation for a preliminary synthesis of a wearable cable-driven parallel robot for wrist joint rehabilitation. Specifically, the synthesis focuses on defining an ad hoc geometric efficiency index to maximise the effective force required to achieve flexion-extension, radial-ulnar deviation and pronation-supination movements with the lowest possible cable tension. To consider lightness and wearability, the results of the synthesis are weighted to obtain a light and compact system that will be developed.