Stiffness Effect on Periodic Locomotion of Legged Robot Based on Dimensional Analysis and Fixed Points Search Method

The high complexity of dynamic equations of legged robot with spring legs often leads to difficulty in analyzing the influence of spring stiffness on periodic locomotion of legged robots. To deal with this problem, this paper firstly applies dimensional analysis method to determine the relationship among physical quantities. And through the dimensionless processing for dynamic equations, the relatively independent expression of the spring stiffness, i.e. relative spring stiffness, is obtained, which can lower down the coupling degree among the physical quantities in dynamic equations. Then, the fixed point distribution of the dynamic model for legged robot, with respect to different stiffness, is presented based on the fixed point theory. Finally, the regularities of influence of spring stiffness on the fixed point are summarized by analyzing the simulation results.