Movement stability criterion and its application to gait planning of a quadruped robot

For the design and application of quadruped robots, the movement stability is very important. In this paper, we proposed a movement stability criterion, which can be used for the design, gait planning and control of a quadruped robot. Such criterion considers the geometry and mass properties (mass and mass of center) and their variation during movement, hence overcoming the shortcomings of previous works. The dynamic model is derived and the effects of the weighty leg of the total gravity center is provided. Then, the relationship between stability margin and design parameter of robot is established. As a practical application, an effective gait planning method is addressed by using the criterion. It adjusts the center of gravity to vary along desired path. Finally, a quadruped turtle robot is developed. It is composed of four 3-DOF lightweight modularized legs, an elastic neck with continuous curvature, a shell opening and closing device, a carbon fiber torso frame and control system. Based on it, some experiments are implemented to verify the proposed method.