Standing up motion support system for wheelchair users

Standing up motion would be effective for maintaining or improving the function of motor and circulatory system. By standing up in daily life, wheelchair users with lower limbs motor dysfunctions could prevent the development of physiological dysfunctions, such as deep vein thrombosis and disuse syndrome. The purpose of this study is to develop a standing up motion support system for such wheelchair users without any mounting sensors and devices, and to confirm the effectiveness of the developed system through a standing experiment with a wheelchair user who has lower limbs motor dysfunctions. We developed a wheelchair type motion support system and seat reaction force (SRF) sensor. Since the SRF decreases in standing up preliminary motion, the SRF sensor measures the decrease of user's SRF in order to detect the standing up preliminary motion. The system supports standing up motion while SRF decreases less than that during sitting posture. A basic experiment is carried out to confirm the measurement accuracy of the developed SRF sensor. The results of the basic experiment showed that the errors between the true weight and the SRF calculated by the sensor ware within ±10 N. A standing experiment with a spinal cord injury participant who can't stand up by oneself was performed to confirm that the system could detect the user's standing preliminary motion and can support active motion. The results showed that the system started to support user's standing up motion after the system could detect the decrease of the SRF. In addition, the user could stand up actively by using the system. In conclusion, the developed system was effective in helping the wheelchair users to stand up actively in daily life.