ABSTRACT
This chapter presents a class of output functions that leads to computable, closed-form representations of the zero dynamics. It provides a method for choosing the remaining free parameters in the Bezier polynomials to design a walking gait. The chapter explains how to design virtual constraints that will realize a prespecified, period-one walking gait as a periodic orbit of a hybrid zero dynamics. It shows how to systematically modify a given period-one walking gait through hybrid zero dynamics control so as to obtain additional functionality. The chapter also shows that the two-link walker to illustrate some of the flexibility available when designing controllers on the basis of virtual constraints and the hybrid zero dynamics. A passive walking motion on a slope is first found and then a feedback controller is designed that significantly increases the basin of attraction of the passive motion.
