What Is the Proper Gait Pattern for People With Paraplegia Who Wear Powered Exoskeletons?: Re-examining gait patterns of existing powered exoskeletons

Unlike able-bodied humans, people with paraplegia are unable to voluntarily move their legs or waist, so they cannot control their center of gravity (CoG). Powered exoskeletons have been regarded as one of the most significant lower-limb rehabilitation devices in recent years, and existing powered exoskeletons have already been used to assist people with paraplegia to walk similarly to a normal human gait. However, it may not necessarily be the best option for people with paraplegia to walk like able-bodied people because powered exoskeletons are much more limited in their degrees of freedom (DoF) than an able-bodied human body and cannot help people with paraplegia voluntarily control their CoG. Therefore, there is a need for research specifically targeting people with paraplegia wearing powered exoskeletons to develop their own appropriate gait pattern method according to the characteristics of powered exoskeletons. In this study, a new gait pattern, called
forward-leaning walking
(
FLW
), is proposed for the motion control of powered exoskeletons. The proposed method enables transfer of the CoG to the leading leg by using the height difference between the leading and trailing legs. The effectiveness of the proposed gait pattern method was evaluated by tilting the user’s trunk by 1°. The initial frontal acceleration of the user’s CoG increased by 12–16% each time the angle of the tilt of the trunk increased by 1° during the preswing phase. In addition, several sensors were used for quantitative evaluation, and the successful weight shift of the legs of people with paraplegia was monitored. The metabolic cost was also measured to verify the efficiency of the proposed gait method as people with paraplegia walked with powered exoskeletons, the oxygen consumption cost was more than halved, and the locomotion speed tripled compared to the first training session.