The design method of two-degree-of-freedom controller using μ-synthesis

This paper presents the design method of a two-degree-of-freedom (2 DOF) controller system based on an internal structure. The authors show the internal structure of the system and derive the condition which clearly shows the equivalence between the disturbance observer based controller and the generalized 2 DOF controller. They then propose the design method of free parameters using μ-synthesis taking into account the structure of the system and Q tuning so as to satisfy the derived conditions. Finally, the authors show the simulation results of velocity control of a 2-mass system and confirm the effectiveness of the proposed method