Non-time reference gait planning and optimization for a stable bipedal walking

A non-time reference gait planning method is proposed. The usual reference variable, time, is substituted by a non-time variable in gait, so the whole gait-planning phase can be divided into two phases, (1) planning the space walking path: Taking the forward locomotion of upper-body as reference variable, considering the constraint of the environment, the walking path of a robot without collision with other objects is designed, thus the relating locomotion of the parts of the robot is obtained; (2) planning the trajectory of the non-time reference variable: according the constraint of ZMP stability, design the forward locomotion of upper-body. The gait-planning problem is changed to the optimization problem. The optimized gait with good stabilities is obtained by genetic algorithm (GA). This non-time reference gait planning method has advantages in passing obstacles, climbing upstairs or downstairs and other similar situation in which the walking path is specified.