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_infin controller is designed and the robust stability and robust performance criteria are to be handeled with the mu analysis theory.