Gait Planning for Biped Robot Based on Variable Center-of-Mass Height Hybrid Strategy

In order to make the gait of a bipedal robot more human-like and to further improve the efficiency of energy utilisation, this paper combines preview control strategy and a knee extension strategy to design a bipedal robot gait planning method based on a variable centre-of-mass height hybrid strategy. The core idea is to achieve gait stability and coordination by controlling the robot's centre-of-mass height. Firstly, the horizontal centre-of-mass trajectory of the biped robot is generated based on Preview Control strategy with a constant centre-of-mass height; secondly, the vertical centre-of-mass trajectory is generated based on the knee joint extension strategy by trajectory planning of the robot's knee joint; finally, the horizontal and vertical centre-of-mass trajectories and foot point positions are combined by the inverse kinematics of the bipedal robot to plan the offline gait of the bipedal robot with variable centre-of-mass height. The experimental results show that the bipedal robot is able to walk smoothly with the planned gait, with better human-like characteristics, and requires less knee torque than bent knee walking mode with a constant centre of mass height, which improves energy efficiency.