Research on the Walking Modes Shifting Based on the Variable ZMP and 3-D.O.F Inverted Pendulum Model for a Humanoid and Gorilla Robot

The walking modes shifting of a gorilla robot is a kind of movements between biped standing state and quadruped landing state. In this paper, the robot mechanism is reduced to a 3-D.O.F inverted pendulum model with variable pendulum length, and the variable ZMP is defined reasonably as a function related to the inverted pendulum angle. Base on dynamic balance theory, the trajectory equation of robot\´s mass centre during the walking mode shifting is deduced. Furthermore, through inverse kinematics analysis for robot\´s mass center, the trajectories of joint are obtained. Thus method of trajectory generation about walking mode shifting for humanoid and gorilla robot is proposed. In order to verify the correctness of the method, a calculation example of trajectory generation is provided, and the continuing action simulation including biped walking and quadruped landing action, quadruped walking and standing up action is successfully realized. On the basis of above work, the continuing action experiment including biped walking and walking modes transitions for a humanoid and gorilla robot "GoRoBoT" developed by us is also finished