Hierarchical implicit feedback structure in passive dynamic walking

The purpose of this paper is to analyze the stability of Passive Dynamic Walking (PDW) using a linearized analytical Poincare map. In particular, in this paper, we focus on a bifurcation phenomenon in PDW. Although the bifurcation of the walking period is one of the well-known features of PDW, it have not been studied sufficiently so far. Using techniques similar to our previous research, we derive an analytical Poincare map for 2-period walking and discuss the stability of PDW with this map. In addition, we point out that there is a similar interesting structure in this Poincare map.