Figure 7.
Assistance profiles. (a) For each spring stiffness, phantom work loops show the mean moments generated by the exoskeleton over the phantom knee joint. The steep work loops correspond to the stance phase of gait. (b) Mean phantom work loop stiffness (slope) during stance phase loading. (c) Plots of the mean exoskeleton work loops showing the moments over the exoskeleton knee angle. (d) Mean stiffness of the exoskeleton work loops during exoskeleton loading. Error bars denote the standard deviations. (*) = significantly different from all other groups. (1), (2), (3), (4), (5), (6) = significantly different from springs 3.4, 6.1, 9.2, 13.6, 18.0, 21.7 kN m−1, respectively. The p-values for all statistical tests are specified in electronic supplementary material, table S3.