A User-intent Powered Gait Orthosis with Speed Control Developed for Persons with Disability

• Main Authors: Wen-Hao Yang, 楊文豪
• Other Authors: Liang-Wey Chang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/jy7hap

碩士 === 國立臺灣大學 === 醫學工程學研究所 === 106 === 　　Most persons with paraplegia attributed to spinal cord injury, rely on wheelchairs for their daily activities. Lower limb gait orthoses could help them walk to gain physiological benefits and enhance quality of life. However, passive lower limb orthoses have caused detrimental burden on persons with paraplegia. As a result of high energy cost and slow walking speed of these orthoses, an alternative solution has been inevitable. Because of advancements in electric and motor technology, it has been proved that powered lower limb exoskeletons could provide persons with paraplegia enough joint power when walking and improve disadvantages of passive lower limb orthoses. Most powered exoskeletons equip four or more motors to provide joint power currently. In consideration of affordability and lightweight of powered exoskeletons, National Taiwan University’s rehabilitation engineering laboratory in the department of biomedical engineering has developed a user-intent powered gait orthosis(UPGO), where only two hip motors were used and a wireless push-button control was imbedded in the crutches to help persons with paraplegia walking. 　　In this thesis, a second edition of UPGO was studied by adding a pressure sensor in the imbedded push buttons to implement a variable speed control by which users were capable to change their instantaneous walking speed. The purpose of this research was to validate the effectiveness of variable speed control, and investigate whether it could bring more fluent gait, more maneuverability and less power consumption. In the experiment, eight normal subjects wore the UPGO to perform four tasks on both constant speed mode and variable speed mode respectively. Walking speed and cadence was measured through both a 7 m walking and mental loading tests. Hip angular speed was additionally measured through a 7 m walking test. Maneuverability was assessed through an obstacle course and a narrow space task by measuring course and task completion times and the number of obstacle collisions. The electric power consumption was obtained by the time integration of recorded current of the hip motor and calculated operating voltage. The results showed that it appeared that the variable speed mode offered a closer to normal walking in partial gait cycle than its counterpart. In obstacle avoidance and narrow space task, the use of variable speed mode demonstrated lesser contact error. However, it did not reach conclusion that the variable speed operation consumed lesser power because the power consumption depends on the length of stepping time.