Fig. 7

Box Plots and Wilcoxon Rank-Sum Tests of the performance metrics. Data presented for each subject (columns) and each performance metric (rows). The number of repetitions performed by the subjects with each method, and the number of observations (N) of each boxplot is indicated at the bottom of the figure. Subject S1 (Brooke 4) showed a high overall performance completing all three repetitions with all three control methods, and presents the best movement performance when using the FNC method. The low number of repetitions, the low percentage of task completion, and the high tracing error of FNC clearly indicated that subject S2 (Brooke 5) performed better with FSC and sEMG than with FNC. Movements of subject S2 presented significantly lower speed with sEMG than with FSC. Subject S3 (Brooke 6) was not able to effectively use neither of the force-based control interfaces (i.e. no movements completed with FNC and one repetition completed with FSC) and showed a better performance in terms of percentage of task completion and speed with sEMG and could reach almost his entire workspace. (**) indicates p<0.0167