Mechanism analysis and suppression control strategy of frictional impact for humanoid robots

Stability and robustness are the important expressions of intelligent walking ability of biped robots. The Zeno behavior caused by the frictional impact of knee joints affects the stability during the dynamic walking, which has greatly limited robot’s application and efficiency. Based on the analysis of the intrinsic mechanism of Zeno behavior, this paper aims to explore biped walking control methods to provide theoretical basis and key technologies for suppressing Zeno behavior. The internal relationship between Zeno behavior and robot knee joint collision is built by studying the cause of Zeno behavior. An event-based feedback controller is proposed to deal with the problem of stabilization of Zeno periodic orbit. It is achieved adaptive periodic stable walking in complex environment based on event-based and hybrid zero dynamic control strategy, which proposes the stability analysis method based on Poincare return map. Meanwhile, the identify parameters of dynamic equations with Zeno behavior is utilized with genetic algorithm and particle swarm optimization. Finally, the effectiveness of the proposed method is verified by simulations.