An exoskeleton wearable on a body of a human having two legs, the exoskeleton comprising a first HAA joint and a second HAA joint to assist the human with leg abduction and adduction movements that are parallel to a frontal plane, each of the first and the second HAA joints having an actuator, each actuator including a motor and a clutch. The exoskeleton further comprises a sensor system for measuring a combined center of mass of the human and the exoskeleton in the frontal plane and a step width of the human in the frontal plane. The exoskeleton further comprises a controller that outputs adjustment angles for each of the first and the second HAA joints based on the center of mass and the step width. The first and the second HAA joints are respectively rotated based on the respective output adjustment angles.