The Change of Gait Motion During Curvilinear Obstacle Avoidance While Restricted by a Wearable Robotic Device

Lower limb wearable robotic devices designed to aid humans in motion tend to have reduced degrees of freedom (DoF) when compared to human legs. These limit the wearer movement and as a result significantly alter common gait types. One motion that is very integral to everyday life is obstacle avoidance in the form of a curvilinear path. To evaluate the effects a physical assistant robot (PAR) has on such a motion, we conducted a study to compare the gait dynamics of a test subject with and without the PAR restricting their hip movement out of the sagittal plane as they moved around a “S” shaped path. Results showed that hip rotation is the dominant factor which alters natural gait motion with the PAR's restrictions engaged. Center of mass (CoM) trajectories showed that due to rotation restrictions a stable repeatable path was more difficult to obtain when restricted by the device, especially around smaller radii curves. Hip rotation is thus deemed critical to fluid turning and movement of this DoF should be an important factor when designing PAR devices that are used to make curvilinear motions.