Design of Wearable Robotic Support Limbs for Walking Assistance Based on Configurable Support Polygon

This paper presents a new type of wearable assistive device, called Robotic Support Limbs (RSL), to provide balance and load support during standing/walking. Traditional walker typed robots are usually bulky and almost cannot actively adjust their support points. However, the assistive robot can be designed as compact and agile as possible if the robot support points can be altered based on walking phases or walking states. As a kind of Supernumerary Robotic Limb (SRL), RSL has kinematically independent structure that allows it to dynamically change the support positions in coordination with human leg, which makes the human-robot support polygon configurable. First, the concept of configurable support polygon and constant contact motion are introduced. Second, the proposed robot structure and a novel curved rail mechanism as well as a 7 kg prototype are presented and developed. Finally, a robot gait planning strategy is discussed in both standing and walking cases. The main application of RSL is proposed to improve the quality of life for the elderly and targeted to the people with muscle weakness on hand. But not limited to that, RSL can be applied to other potential users, like the leg injured and neuromuscular disorders.