An optimal observer design for 2-inertia system via ILQ design method

This paper presents a novel optimal observer for speed control in 2-inertia dynamic system such as a large scale rolling mill, coupled with flexible shaft which has resonant torsional oscillation. For suppressing oscillation and reducing disturbance load torque, we introduce a full-order observer with concept of Kalman filter on a basis of inverse linear quadratic (ILQ) design method, including disturbance observer. In this paper, the ILQ design method improved by polynomial pole assignment gives an analytical optimal gain, and makes the errors of outputs converge to zero in steady-state. The proposed observer enables to suppress vibration and to control at high precise speed control in the 2-inertia system in spite of the quick speed response.