Ornithoid Gait Generation Based on Parametric Excitation

Abstract

We have applied a parametric excitation method to a kneed biped robot with semicircular feet and have shown that the robot can walk sustainably with only knee torque. A swing-leg of the kneed biped robot has similar mechanism to an acrobot, and many acrobots are controlled in inverse direction like ornithoid walking. These suggest that inverse bending of a knee restores more mechanical energy than forward bending, and hence, the ornithoid walking can be more efficient. In this paper, we first compare the forward bending with the inverse bending for a double pendulum, and show by numerical simulation that the mechanical energy of the inverse bending increases more than that of the forward bending like human walking. We then propose a parametric excitation based ornithoid gait for a kneed biped robot, and show sustainably walking by numerical simulation. Finally, we compare parametric excitation based ornithoid gait with parametric excitation based human gait, and we show that ornithoid gait is more efficeint.

Optimal trajectory design for parametric excitation walking

“…To grow in efficiency, we think that optimization of the physical parameters of the biped robot is needed, for example mass and link length. Another method to grow in efficiency is the parametric excitation based inverse bending walking proposed by Harata et al [9], [10]. We will apply the proposed method to inverse bending walking and then gait become more efficiency.…”

“…Harata et al [6], [7] applied the parametric excitation method to a kneed biped robot, in which up-and-down movement of the center of mass was realized by bending and stretching knee, and showed that sustainable gait was generated by knee torque only. Harata et al [9], [10] also proposed parametric excitation based inverse bending walking in which the knee was bent in inverse direction to human.…”

An optimization method for the reference trajectory of parametric excitation walking

“…There are 21 parameters, 2,4,5) and the maximum bending angle A m , in the definition of h. We impose 14 constraints, 8 of which are that the first and second derivatives at t = t 1 , t 3 , t 4 , t 6 equal zero, and the remaining six are that the first to third derivatives at points t 2 , t 5 are continuous. .…”

“…A children's swing is an example using parametric excitation principle. Harata et al 4,5 also proposed parametric excitation-based inverse bending walking in which a swingleg knee was bent in the inverse direction to human. Harata et al 2,3 applied the parametric excitation method to a kneed biped robot, in which the up-and-down motion of the CoM was realized by bending and stretching a knee, and showed that sustainable gait was generated by knee torque only.…”

“…Harata et al 2,3 applied the parametric excitation method to a kneed biped robot, in which the up-and-down motion of the CoM was realized by bending and stretching a knee, and showed that sustainable gait was generated by knee torque only. Harata et al 4,5 also proposed parametric excitation-based inverse bending walking in which a swingleg knee was bent in the inverse direction to human.…”