Non-horizontal ricochetal brachiation motion planning and control for two-link Bio-primate robot

Ricochetal Brachiation is a sophisticated locomotion for Bio-primate robot. It requires precise cooperation of three different types of locomotion. The tight coupling of locomotion and underactuated characteristics is the main difficulties for realizing ricochetal brachiation. Moreover, for the non-horizontal ricochetal brachiation, which refers brachiating among supporting bars with different heights, another difficulty orients from the asymmetric property of the flight trajectory. To solve the locomotion coupling problem, by building and analyzing the segmented dynamic and kinematic models and considering the constraint and switching condition, this paper proposes a flexible, comprehensive and adaptive ricochetal brachiation motion planning algorithm to obtain the pre-flying posture and post-flying posture. Also, the horizontal and vertical differences between adjacent supporting bars are modeled and included, which makes the algorithm applicable for general configurations. To eliminate the difficulty brought by under-actuated characteristics, virtual constraint based trajectory planning and tracking control method is adopted to ensure that the system can arrive in the pre-flying posture accurately. Finally, a ricochetal brachiation simulation model is built and the results show the effectiveness of the proposed trajectory planning and control strategy.