Figure 5.

Initial phase ϕ₀-dependency of eigenvectors of the three dominant FMs of . In this example, P_a = P_k = P_h = 700 Nm rad⁻¹, for which the LC is unstable, and the dominant FMs, except the single unity FM, are a pair of complex conjugates λ₁ and with and one real λ₃ < 1, for which eigenvectors are v₁(ϕ₀), and , respectively. In each panel, 18 element-values of the vectors and are colour-coded as indicated by the vertical colour-code bar in the right-most of each panel. The phase origin corresponds to the left heel-contact throughout the paper. Dotted squares in each panel indicate the double support phases. One can observe that each eigenvector changes in a continuous manner basically as the function of ϕ₀, but it exhibits abrupt changes at the heel-contact and toe-off events.