The Achilles is a powered exoskeleton that powers the human ankle. The device has been used in healthy subjects to reduce the metabolic costs of walking and in the Symbitron project to increase the walking speed of incomplete spinal cord injured subjects.
W. van Dijk, C. Meijneke, and H. van der Kooij, “Evaluation of the Achilles Ankle Exoskeleton.,” IEEE Trans Neural Syst Rehabil Eng, vol. 25, no. 2, pp. 151–160, Feb. 2017.
F. Dzeladini, A. R. Wu, D. Renjewski, A. Arami, E. Burdet, E. van Asseldonk, H. van der Kooij, and A. J. Ijspeert, “Effects of a neuromuscular controller on a powered ankle exoskeleton during human walking,” presented at the 2016 6th IEEE International Conference on Biomedical Robotics and Biomechatronics (BioRob), 2016, pp. 617–622.