Dynamic Stability Analyses Based on ZMP of a Wheel-based Humanoid Robot

For wheel-based humanoid robot, the dynamic stability is also an important question just like for biped robot. This paper unites the new recursive Newton-Euler method for dynamic modeling and the ZMP concept and then obtains the ZMP model of the robot. The merit of this model is that it is a function of the position, velocity and acceleration of joints in joint space and easier to realize realtime control due to less calculation. Calculation and simulation show that the waist motion takes the main effect on the dynamic stability of the robot. Using the compensation of motion of the waist, the robot can realize dynamic motion. This paper also presents the concepts of the valid stable region and stable degree for the wheel-based robot.