External control of walking direction, using cross-wire mobile assist suit

In this paper, we control the walking direction of a subject using an assistive robotic device for the first time, using the internal/external rotation hip torque generated by our cross-wire assist suit to induce turning gait. The cross-wire assist device is a soft exosuit with four independently controllable actuators located around at hip joint, and selective actuation allows for the generation of internal/external rotational torque. Turning was most effectively induced using external rotation for the inside leg and internal rotation for the outside leg, which is a combination of human step turning strategy and ‘ipsilateral crossover’ spin turning strategy. The degree of turning increased with applied force level, and multi-subject testing showed that the walking direction all subjects were capable of being modified (average 16.2 degree/m for 80 N); however, there was large variation between subjects.