Development of an elbow-supporting device to assist standing-up motion

• Published in: ROBOMECH journal 2015-05, Vol.2 (1), p.1, Article 10
• Main Authors: Eto, Haruna, Nakamoto, Hideichi
• Format: Article
• Language: English
• Subjects: Artificial Intelligence; Computational Intelligence; Control and Systems Theory; Development Report; Engineering; Mechatronics; Robotics and Automation
• ISSN: 2197-4225; 2197-4225
• DOI: 10.1186/s40648-015-0032-0

In modern-day Japanese society, which is an aging society, an important issue is how to maintain the physical strength of elderly people. There are many studies to develop devices assisting with standing-up motion, because standing-up motion is a most important motion in daily life. Most of these studies suggested the devices to be placed in front of user’s body or be used on the premise that a user balances between the right body and left body. And, they can assist standing-up motion effectively but their sizes are too large. One of the reasons why they cannot have been put into practical use seems to be that they are used with limiting a mounting location and interfere in the other motions of users. Therefore, we suggest an elbow-supporting device to assist standing-up motion, because we noticed that posture where an elbow is leaned on is generally comfortable and make user’s upper body stable with supporting weight. And we developed a support device consisting of an armrest with two degrees of freedom. Using this device, a user can apply a load not to lower limbs but to the armrest with user’s one elbow. This device on handrails is space-saving and doesn’t interfere in the other motion of users. In this paper, we measured the surface electromyography (EMG) of three subjects’ rectus under two conditions: not using any device and using the developed device. As the result, there is significant difference in the reduction in rectus femoris muscle activity when using the device. And we examined the suitable initial posture using this device and found that bending forward and tilting to an armrest are suitable initial posture. As a consequence, it was found that the suggested device can reduce the activity of lower limbs of a subject in that specific initial condition. Finally, in spite of a compact size of device, we showed a certain effect to assist standing-up motion in use an elbow-supporting device.