Towards a Nonlinear Model Predictive Control for Quadrupedal Locomotion on Rough Terrain

In this extended abstract, we give a short intro- duction to our ongoing work [1] on a real-time Nonlinear Model Predictive Control (NMPC) tailored to a legged robot for achieving dynamic locomotion on a wide variety of terrains. We introduce a mobility-based criterion to define an NMPC cost that enhances the locomotion of quadruped robots while maximizing leg mobility and staying far from kinematic limits. In addition, we include a cost term to regularize Ground Reaction Forces (GRFs) inside friction cone. We demonstrate the efficiency of our approach executing an omni-directional motion on our Hydraulically actuated Quadruped (HyQ) robot and showing in simulation a walk into a V-shaped chimney