title: Bifurcation and chaos in the simple passive dynamic walking model with upper body.
abstract: We present some rich new complex gaits in the simple walking model with upper body by Wisse et al. in [Robotica 22, 681 (2004)]. We first show that the stable gait found by Wisse et al. may become chaotic via period-doubling bifurcations. Such period-doubling routes to chaos exist for all parameters, such as foot mass, upper body mass, body length, hip spring stiffness, and slope angle. Then, we report three new gaits with period 3, 4, and 6; for each gait, there is also a period-doubling route to chaos. Finally, we show a practical method for finding a topological horseshoe in 3D Poincaré map, and present a rigorous verification of chaos from these gaits.
authors.affiliation: Key Laboratory of Industrial Internet of Things and Networked Control, Ministry of Education, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Qingdu
authors.initials: Q
authors.lastname: Li
authors.affiliation: Key Laboratory of Industrial Internet of Things and Networked Control, Ministry of Education, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Jianli
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Mathematics, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Xiao-Song
authors.initials: XS
authors.lastname: Yang
mesh_terms: D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D005684:Gait / Q000502:physiology*; D006615:Hip / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D017711:Nonlinear Dynamics; D016138:Walking / Q000502:physiology*