Title
MPC for Humanoid Gait Generation: Stability and Feasibility
Abstract
In this article, we present an intrinsically stable Model Predictive Control (IS-MPC) framework for humanoid gait generation that incorporates a stability constraint in the formulation. The method uses as prediction model a dynamically extended Linear Inverted Pendulum with Zero Moment Point (ZMP) velocities as control inputs, producing in real time a gait (including footsteps with timing) that realizes omnidirectional motion commands coming from an external source. The stability constraint links future ZMP velocities to the current state so as to guarantee that the generated Center of Mass (CoM) trajectory is bounded with respect to the ZMP trajectory. Being the MPC control horizon finite, only part of the future ZMP velocities are decision variables; the remaining part, called tail, must be either conjectured or anticipated using preview information on the reference motion. Several options for the tail are discussed, each corresponding to a specific terminal constraint. A feasibility analysis of the generic MPC iteration is developed and used to obtain sufficient conditions for recursive feasibility. Finally, we prove that recursive feasibility guarantees stability of the CoM/ZMP dynamics. Simulation and experimental results on NAO and HRP-4 are presented to highlight the performance of IS-MPC.
Year
DOI
Venue
2019
10.1109/TRO.2019.2958483
IEEE Transactions on Robotics
Keywords
DocType
Volume
Gait generation,humanoid robots,internal stability,legged locomotion,predictive control,recursive feasibility
Journal
36
Issue
ISSN
Citations 
4
1552-3098
4
PageRank 
References 
Authors
0.41
16
4
Name
Order
Citations
PageRank
Nicola Scianca1124.75
Daniele De Simone2152.12
Leonardo Lanari34311.31
Giuseppe Oriolo41270100.12