Preliminary test of a zero-torque controlled exoskeleton on a treadmill

Abstract

Variable stiffness actuators help to guarantee a safe human interaction when it is used as the active joints in lower-limb exoskeletons. Therefore, we designed a unilateral exoskeleton consisting of a mechanical-rotary variable impedance actuator (MeRIA) assisting the human knee. In this paper, a first walking trial with a healthy, human subject has been carried out on a treadmill to validate the mechanical performance of the actuator. Even though the implemented zero-torque controller does not yet actively strengthen the human subject, the preliminary test shows that the exoskeleton can follow the human motion while providing a low impedance and thus a patient-cooperative behavior during walking.