Torque shaping control for initial unstable passive dynamic walker

The gait stability of Passive Dynamic Walking is sensitive to the initial walking state, which must be adjusted precisely for continuous gaits. A novel torque shaping control method is proposed to obtain the initial stable gait for the passive dynamic walker within a gait period in this paper. Meantime, the stability of the system with this controller is proved. Therefore, the unstable initial state can be adjusted to generate stable limit cycles in the following steps. The performance of this controller is verified by simulations. It is more effective to against the disturbance and has faster convergence speed than traditional PD control.