Quadruped free gait generation for straight-line and circular trajectories

A method of free gait generation is proposed utilizing the primary/secondar y gait for both straight line and circular body trajectories. The primary g ait is a fixed sequence of leg transfers with modified leg-ends kinematic l imits according to the presence of obstacles, while the secondary gait is a flexible gait which is generated to adjust the leg-end position. The prima ry gait is generated considering the following four constraints: stability constraint; kinematic constraint, sequential constraint and neighboring con straints. A generalized reference coordinate (GRC) system is introduced to describe the vehicle motion. Using the GRC system, all constraints and obst acle influences are expressed by only one set of equations despite the diff erence of motion mode, The efficiency of free gait generation is improved w ith the proposed method, and the trajectory of the vehicle body can be desi gned more naturally. Simulation results are given to demonstrate the effici ency of the proposed methodology.