Robust Position Regulation of a Seesaw Actuated by a Humanoid

This paper presents the implementation of a robust control technique applied within a standard multi-objective robot controller for humanoid robots. The challenge is to regulate the angular position of a seesaw actuated by a humanoid on it, which is a complex multitask involving the humanoid balance, the motion to project its weight into its feet to move the seesaw, and the seesaw motion itself. An accurate model of the seesaw is not available, therefore, a model-free approach based on super twisting sliding mode control is proposed; besides, the stability of the closed-loop system with the proposed technique is proved using the Lyapunov’s direct method. The proposed controller was applied to a multi-robot model compound by the HRP-4 humanoid and a passive seesaw model, and it was tested using a physics-engine simulation environment. The presented results show that the challenge of regulating the seesaw was successfully achieved by means of the proposed robust control.