In this paper, Passive Dynamic Autonomous Control (PDAC), the novel control method we proposed previous paper, is applied to the sagittal motion of biped walking. PDAC expresses the robot dynamics as an 1-dimensional autonomous system based on the two concepts: 1) point-contact 2)
Virtual constraint (proposed by Grizzle and Westervelt
et al. previously). Due to autonomy, this approach has two following notable point: 1) there is a conservative quantity2) period from foot-contact to next foot-contact can be obtained by integrating1D dynamics with respect to time. This paper proves the convergence of the conservative quantity under the condition of constant step-length by Theorem of Lyapunov. In addition, the coupling method of the sagittal and lateral motion that takes advantage of point2) is designed. Finally, by means of PDAC and these methods, natural3D dynamic walking based on the robot inherent dynamics is realized.
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