A. M. Dollar and H. Herr. Design of a quasi-passive knee exoskeleton to assist running, Proceedings of the 2008 IEEE/RSJ International Conference on Intelligent Robots and Systems, Nice, France, Sep. 2008.

Abstract

In this paper we describe the design and preliminary evaluation of an energetically-autonomous powered knee exoskeleton to facilitate running. The device consists of a knee brace in which a motorized mechanism actively places and removes a spring in parallel with the knee joint. This mechanism is controlled such that the spring is in parallel with the knee joint from approximately heel-strike to toe-off, and is removed from this state during the swing phase of running. In this way, the spring is intended to store energy at heel-strike which is then released when the heel leaves the ground, reducing the effort required by the quadriceps to exert this energy, thereby reducing the metabolic cost of running.