Quadruped free gait generation combined with body trajectory planning

A method of free gait generation for both straight line and circular body trajectories is proposed utilizing the primary/secondary gait. The primary gait is a fixed sequence of leg transfers with modified legend kinematic limits according to the obstacle presence, while the secondary gait is a flexible gait which is generated to adjust the leg-end position. The primary gait is generated by considering the following four constraints: stability constraint, kinematic constraint, sequential constraint and neighboring constraints. Primary gait parameters are modified by the influence of the obstacle. Using a generalized reference coordinate system, all constraints and obstacle influences are expressed by only one set of equations despite the difference of motion modes. With the proposed method, the free gait could be efficiently generated with consideration of body trajectory planning. Simulation results are given to demonstrate the efficiency of the proposed methodology.