Figure 8.
Eigenfrequency and stability of the anti-phase mode for the double inverted pendulum model with continuous active feedback control (on-model) on the Dh-Ph parameter plane for varied parameter values of Kh, Bh, Da, and Pa, where Dh and Ph are the derivative and proportional gains of the active feedback controller at the hip joint, respectively, and Da and Pa are the derivative and proportional gains of the active feedback controller at the ankle joint, respectively. See legend of Figure 7 for color identification details. In each panel, the area surrounded by the black curves represents the stability region. (A) Example case (Kh, Bh, Pa, Da) = (0.2mgh, 50, 1.0mgh, 0). (B) Systematic exploration for various values of Kh, Bh, Da, and Pa. In this study, the passive viscoelasticity at the ankle joint was fixed at (Ka, Ba) = (0.8mgh, 4.0).