Robust control frequency analysis of a moving walking bipedal robot

Dynamic equations of the biped robots are easily obtained by the Lagrangian method. Because of terrible nonlinearity of these dynamic equations, the actuator's dynamic is employed to linearize these equations. By this way, the heavy nonlinear equations are replaced with a second order linear system which their coefficients are achievable by the various identification methods. Here Least Square method is utilized to determine these second order transfer function's coefficients. Employing a set of linear transfer function for each joint and also considering unstructured uncertainty, an H∞ controller is designed and the Robust Stability and Robust Performance criteria are to be handeled with the μ analysis theory.