Abstract
Generally, the specifications of the robustness and the disturbance or noise applied to the control system are often provided in frequency domain. The traditional observer design is based on a state space structure in time-domin representation of a linear system. In this paper, a robust observer against disturbances is designed by using a transfer function in frequency domain. This method is composed of a diophantine equation including disturbance characteristics, and only three steps are required for the design. We can directly construct an estimation error dynamics depending on the input/output disturbance or noise frequency characteristics. The proposed method has a disturbance-robustness and its design example is presented through simulation.
