Intermittent Gait Planning Method of Quadruped Robot Based on Velocity Vector

In order to ensure omni-directional stable moving for a quadruped robot with high payload, an intermittent gait planning method based on velocity vector is proposed. In this method, intermittent gait is selected as the main gait, and the translational and rotational velocity vectors are mapped to the turning around the center of rotation. Firstly, the coordinate of the center of rotation is derived from the turning centre theory, and the maximum rotation velocity is calculated according to the workspace of foot. Then, the starting position of the supporting phase is designed under the constraint of stability margin. To satisfy the no-impact condition, a modified cycloid curve trajectory planning method of the swinging leg is adopted. An incremental trajectory planning method is proposed, which can be easily realized to generate continuous motion commands by programming. Then the requirements are analyzed from four aspects:stability margin, continuity, moving speed and workspace, and the corresponding method of parameters design is put forward. Finally, the comparison experiment is carried out among three gaits respectively by using virtual prototype and physical prototype, and the results show that the gait has the least shaking measurements and variances when α=0.5. The results demonstrate that this method guarantees continuous and omni-directional moving trajectory of the quadruped robot with high payload and has good stability.