Fig 1.
A 3-dimensional render of the BENCH apparatus.
Fig 2.
Measurements of the chair, musculoskeletal model and contact geometry (yellow circles).
Table 1.
Subtask and end of the kinematic and the modelled phases.
Fig 3.
STS cycle described according to their kinematics and to the controllers.
Table 2.
Control variables for both controllers.
Table 3.
Phase-dependent penalizations in the cost function for the 4-phases controller optimization.
Table 4.
Phase-dependent penalizations in the cost function for the 2-phases controller optimization.
Table 5.
Comparison between algorithms for detection of kinematic phases.
Table 6.
Comparison of the three first phases between experimental, 4-phases and 2-phases model.
Table 7.
Comparison between 4-phases controller and 2-phases controller along the STS simulation.
Fig 4.
Experimental (grey) and 4-phases controller (green) joint angles [deg] comparison (mean ± std).
Blue vertical lines: experimental cycle times; green vertical lines: 4-phases controller cycle times. Cross-correlation coefficient: r(hip) = 0.99 (Δ = 0%), and r(knee) = 0.93 (Δ = 0%), r(ankle) = 0.68 (Δ = -25%).
Fig 5.
Experimental (grey) and 4-phases controller (green) muscle activation comparison (mean ± std).
Activations is normalized between 0.1 (tonic activation) and 1. Blue vertical lines: experimental cycle times; green vertical lines: 4-phases controller cycle times. Cross-correlation coefficient: r(SOL) = 0.45 (Δ = 0%), r(GAS) = 0.93 (Δ = 0%), r(TA) = 0.31 (Δ = 12%), r(VAS) = 0.96 (Δ = 0%), r(RF) = 0.51 (Δ = 60%), r(BF) = 0.77 (Δ = 0%), r(GLU) = 0.96 (Δ = 0%).
Fig 6.
Comparison (mean ± std) of the reaction forces [N for the 4-phases controller.
Grey: experimental data, green: simulated data; blue vertical lines: experimental cycle times; green vertical lines: 4-phases controller cycle times. rFseat = 0.86, Δ = -3%; rFground = 0.91, Δ = 0%.
Fig 7.
Experimental (grey) and 2-phases controller (orange) joint angles [deg] comparison (mean ± std).
Blue vertical lines: experimental cycle times; orange vertical lines: 2-phases controller cycle times. Cross-correlation coefficient: r(hip) = 0.99 (Δ = 0%), and r(knee) = 0.97 (Δ = 0%), r(ankle) = 0.67 (Δ = -8%).
Fig 8.
Experimental (grey) and 2-phases controller (orange) muscle activation comparison (mean ± std).
Activations is normalized between 0.1 (tonic activation) and 1. Blue vertical lines: experimental cycle times; orange vertical lines: 2-phases controller cycle times. Cross-correlation coefficient: r(SOL) = 0.65 (Δ = 0%), r(GAS) = 0.79 (Δ = 0%), r(TA) = 0.58 (Δ = 11%), r(VAS) = 0.85 (Δ = 3%), r(RF) = 0.48 (Δ = -18%), r(BF) = 0.83 (Δ = 3%), r(GLU) = 0.96 (Δ = 0%).
Fig 9.
Comparison (mean ± std) of the reaction forces [N] for the 2-phases controller.
Grey: experimental data, orange: simulated data; blue vertical lines: experimental cycle times; orange vertical lines: 2-phases controller cycle times. rFseat = 0.96, Δ% = 0; rground = 0.90, Δ% = 3.