Abstract: Aiming at the demand for stable walking of quadruped robots,a stability analysis and planning research of the backward gait of quadruped robot was carried out. Firstly,the structure of the legged robot was introduced. The motion coordinate system was established by D-H method,and the auxiliary action parameters were preliminarily determined. Then,the stability margin index was used to characterize the static and dynamic stability of the quadruped robot,and the relationship between the center position of gravity and time was calculated according to motion parameters and joint drive functions. Next,in the gait design process of quadruped robots,the influence of leg and head to tail movements on the center of gravity of the quadruped robot was analyzed,and the full-cycle action sequence of the backward gait was planned through active and auxiliary actions,and the action parameters of the backward gait were determined. Finally,the feasibility and effectiveness of the proposed method were verified by virtual prototype simulation and physical prototype experiment,which provides theoretical method support for gait analysis of quadruped robot.

Key words: quadruped robot, backward gait, stability margin, stability