Double support phase analysis and ZMP calculation from restriction forces

Among all the articles of human robots there are very few dedicated to the double support phase. A lot of researches consider this phase as an instantaneous transition between the single support phases for one leg to another in the biped gait. So we decided to focus our work in this direction and study the overactuated system that arises from the sub-actuated free-flyer humanoid with restrictions on both feet. The other focus is the ZMP concept, which has been very controversial since it was presented. Specially some questions arise: What happens when the ZMP is outside the support polygon? What happens with the ZMP in the flying phase of a biped robot? How to use the ZMP in uneven terrains? There has been a notable effort in generalize this concept in the late decade, but we think no one had achieved it in a definite way.