Force Assistance Control for Standing-Up Motion

Abstract

In our current research, we are developing a power assistance system for standing up motion. Our developing system realizes the standing up motion using the support bar with two degrees of freedom and the bed system which can move up and down. In this paper, we develop the control scheme which realizes the natural standing up motion with fewer loads to the patient. For developing control scheme, we investigate the standing-up motion of aged people who requires to power support and typical standing up motion by nursing specialist. Comparing with two motions, we set the reference of standing-up motion with our system and we discuss the required assistance force during standing up. Our key ideas are two topics. One topic is control reference using zero moment point. Zero moment point is useful index which shows stability of the patient's posture. The other topic is combination of force and position control. According to the patient's posture during standing up, our control system select more appropriate control method from them. The performance of our proposed control scheme is experimented by computer simulations.

A robotic walker with standing assistance

“…In standing up motion of Kamiya scheme, we can divide the standing up motion into four phases as table 2 [8]. In first phase, the patient still sits and inclines his trunk to forward direction.…”

“…[8] We assume the standing up motion is symmetrical and we discuss the motion as movement of the linkages model on 2D plane. [11] We measure the angular values among the linkages, which reflect the relationship of body segments.…”

“…Our system is based on a walker which is popular assistance device for aged person in normal daily life and realizes the standing up motion using the support pad which is actuated by the manipulator with three degrees of freedom. For using the remaining physical strength, our system uses the motion pattern which is based on the typical standing up motion by nursing specialist as control reference [8].…”

Rehabilitation walker system for standing-up motion

“…Kamiya [10] proposed the standing up motion which uses remaining physical strength of the patients maximum based on her experience as nursing specialist. In our previous work, we analyze this standing up motion and find that Kamiya scheme is effective to enable standing up motion with smaller load [8]. We assume the standing up motion is symmetrical and we discuss the motion as movement of the linkages model on 2D plane [11].…”

“…The patient leans on the pad and grasps the arm holder during standing up with our assistance system. This assistance posture of the patient is based on the assistance scheme of nursing specialist [8]. Bar type (b) consists of the pad and the grip bar.…”