How Should Control and Body Dynamics be Coupled? A Robotic Case Study

Over the past decade, it has been widely recognized that the emergence of intelligence is strongly influenced by not only control systems but also their embodiments, that is the physical properties of robots' bodies. This implies that the control dynamics and its body dynamics cannot be designed "separately" due to their tight interdependency, which is significantly different from the traditional design approach on a "hardware first, software last" basis. Now a question arises: how should these two dynamics be coupled?; what sort of phenomena will emerge under the so-called "well-balanced" design? In spite of its importance, to our knowledge, still very few studies have explicitly investigated this mutual interaction. In light of these facts, this study is intended to deal with the interaction dynamics between control and mechanical systems, and to analytically and synthetically discuss the "relationship as it should be" between the two dynamics. To this end, a decentralized control for a multi-legged robot is employed as a practical example. The result derived indicates that the convergence of decentralized gait control can be significantly ameliorated by modifying its interaction dynamics between the control and mechanical systems to be implemented.