Mixed-integer programming for automatic walking step duration

This paper presents a mixed-integer model predictive controller for walking. In the proposed scheme, mixed-integer quadratic programs (MIQP) are solved online to simultaneously decide center of mass jerks, footsteps positions and steps durations while respecting actuation, geometry, and contact constraints. Simulation results show that this MIQP scheme is able to keep balance while a fixed step duration controller fails in situations where the robot faces very strong disturbances.