Stabilizing bipedal walking on posts through multiple constraints

Abstract

Adaptability of the human locomotion system has been studied from the theoretical viewpoint of dynamical systems. The structure of a dynamical system consists of its time evolution rule, known simply as the dynamics, and its constraints, such as the initial states or boundary conditions that determine future convergent states. Initial state coordination by the system itself is the key to autonomous adaptive mechanisms. Exploring such mechanisms, our previous studies have focused on the variables encoding the attractor basins, called global variables. Global variables have been shown to enable the system to adapt to perturbations, by coordinating the initial states (constraints) of the system. Thus, initial state coordination by the global variables has been proposed as a mechanism for self-production of the constraints by a system. The adaptability of human locomotion extends to active integration into its locomotion of the motion of environmental objects such as walking on high-heeled shoes or on posts erected unstably. Dealing with bipedal walking on posts, this study expands the mechanism for self-production of the constraints. This study proposes a multiple structure for self-produced constraints and a framework for their description.