A body weight support system extension to control lateral forces: realization and validation

Body weight support systems are frequently used as part of robotic gait training to provide unloading in order to help subjects perform walking, but can also induce stabilizing forces and render the task of maintaining balance less challenging. In this paper, a two-dimensional body weight support system extension is presented which reduces lateral forces induced on the subject by means of linearly translating the cable pulley according to lateral movements of the subject. It is demonstrated that the system accurately tracks lateral movements of the pelvis at different levels of vertical support load and thereby lowers the induced lateral forces. The system will be used in advanced robotic body weight supported treadmill walking incorporating a balance training element.