Safe and comfortable assistance for elderly during lie-to-sit transition

While assisting elderly in mobility tasks (such as walking, sit-to-stand, and lie-to-sit etc.) the elderly and robots work cooperatively and remain in continuous physical contact during the task. In order to realize a safe and comfortable assistance to elderly, the natural motion patterns of the elderly during a particular task should be respected and augmented by the robot. This paper is focused on designing robot motion paths that accommodate the natural movement patterns of elderly and are based on modeling the caregivers' actions reported in the biomechanics and elder-care literature. As an example, one such motion path for lie-to-sit and sit-to-stand activities is implemented on SpiderBot-II and experimental results are reported in the paper. Proposed motion path is compared with conventional motion path by evaluating through quantitative safety and comfort indices for mobility assistance robots.