Provably Stabilizing Controllers for Quadrupedal Robot Locomotion on Dynamic Rigid Platforms

Creating controllers for quadrupedal robot locomotion on platforms that exhibit dynamic behaviors, which are herein termed as dynamic platforms, poses a challenging problem because of the complexity of the associated hybrid, time-varying robot dynamics. Towards tackling this challenge, this article focuses on controller design for quadrupedal robot locomotion on dynamic rigid platforms, which are floating-base platforms with a rigid surface. The main contribution of this article is the derivation of a control approach that realizes stable quadrupedal robot locomotion on dynamic rigid platforms of known motions through the provable stabilization of the hybrid, time-varying robot control system. The control approach is synthesized based on the formulation of the robot model as a hybrid, time-varying system and the analysis of the closed-loop control system through the construction of multiple Lyapunov functions. Simulation and experimental results confirm the effectiveness of the proposed control approach in guaranteeing the stability and robustness of quadrupedal robot walking on dynamic rigid platforms.