Standing assistance control using a physical strength of a patient with load estimation

Abstract

In our current research, we have developed a novel standing assistance system for an elderly person. Our developing assistance system is designed compactly for family use. Our system is based on a robotic walker with novel manipulator mechanisms on its body with four parallel linkages. In this paper, we propose the assistance control scheme which can use a remaining physical strength of a patient. In general, a previous assistive device does not require the patient to use own physical strength and it causes the decreasing the physical strength of elderly people. Our key ideas are two topics. One is the real-time load estimation scheme using a human model with measuring information by our assistance system. Using this scheme, our system can change the assistance force based on the estimated results. The other is novel control scheme which consists of position and damping control. Our proposed scheme can change two control modes frequently and using this function, our assistance device can reduce a part of the load which the patient wants to reduce. This means the patient can choose two functions with our standing assistance device; (1) reducing the load for easy to stand up by own physical strength or (2) using the physical strength maximally during standing motion for a rehabilitation purpose.