Review and descriptive investigation of the connection between bipedal locomotion and non-prehensile manipulation

This paper investigates the connection between non-prehensile manipulation, specifically juggling, and legged locomotion, focusing on biped robots. In this direction, the hybrid nature of juggler robot dynamics and biped robots, the zero moment point stability, and the non-prehensile dynamic grasping conditions are provided and analysed. The similarities between juggling actions and bipedal robot locomotion are discussed. The descriptive and mathematical analysis demonstrates many similitudes between juggler systems with cubic objects and flat-feet biped robots in throwing, catching, and stabilisation phases, and between juggler actions with impact and point-feet legged robots in their switching (hybrid) dynamic behaviours. Finally, a common control framework based on the zero dynamic concept and integral sliding mode approach is proposed, and it applies to both classes of non-prehensile juggler systems and biped robots. To test the performance of the devised control system, a three-degrees-of-freedom juggler robot and a two-link walker are selected as case studies, whose simulation results demonstrate the effectiveness and feasibility of the proposed unified control framework for both systems