Optimized humanoid walking with soft soles

In order to control more efficiently the feet-ground interaction of humanoid robots during walking, we investigate adding outer soft (i.e. compliant) soles to the feet. The deformation subsequent to the contact of the soles with the ground is taken into account using a new walking pattern generator and deformation estimator. This novel humanoid walking approach ensures that the desired zero moment point for stability requirement is fulfilled. We validate our new controller using the HRP-4 humanoid robot performing walking experiments with and without the estimator. Also, to test the robustness of our approach and to obtain low-energy walking, we performed different walking motions.