A novel assist-as-needed control method to guide pelvic trajectory for gait rehabilitation

Pelvic motion plays an important role in human locomotion. Any abnormality of the pelvic motion during walking, such as asymmetry or altered range of motion, can affect gait stability and energy consumption [1]. In this work, we propose a new control methodology to guide and correct the human pelvic motion in the transverse plane during walking. An assist-as-needed paradigm was used to generate forces on the pelvis to guide a person to follow a new pelvic trajectory. An experiment was conducted with healthy subjects to follow an extended version of their baseline pelvic trajectory using the proposed control strategy. During the experiment, a cable-driven pelvic robot was used to apply the guidance forces in the transverse plane without adding external kinematic constraints on the pelvis. Experimental results showed that the subjects adapted their pelvic motion and retained the modified pelvic trajectory after the training. These results suggest that this strategy may be explored to correct abnormal pelvic trajectory of different patient groups.