Adaptive step duration in biped walking: a robust approach to nonlinear constraints

Néstor Bohórquez (1) , Pierre-Brice Wieber (1)

1 BIPOP - Modelling, Simulation, Control and Optimization of Non-Smooth Dynamical Systems

When a biped robot is walking in a crowd, being able to adapt the duration of steps is a key element to avoid collisions. Model Predictive Control (MPC) schemes for biped walking usually assume a fixed step duration since adapting it leads to a nonlinear problem, in general. Nonlinear solvers do not guarantee the satisfaction of nonlinear constraints at every iterate and this can be problematic for the real-time operation of robots. We propose a method to make sure that all iterates satisfy the nonlinear constraints by borrowing concepts from robust control: we make the problem robust to nonlinearities within some bounds. These bounds are linear with respect to the variables of the problem and can be adapted online.

Domaines: Automatique; Robotique [cs.RO]

Néstor Bohórquez, Pierre-Brice Wieber. Adaptive step duration in biped walking: a robust approach to nonlinear constraints. IEEE RAS International Conference on Humanoid Robots 2017, Nov 2017, Birmingham, United Kingdom. pp.724-729, ⟨10.1109/HUMANOIDS.2017.8246952⟩. ⟨hal-01649781⟩