Parameterization of High Order PI Observers for Second-order Linear Systems

The design of high-order proportional plus integral (PI) observers in second-order linear systems is investigated. Based on the solutions to a so-called generalized Sylvester equation, a parametric method to solve this design problem is proposed. This method presents the parametric expressions for the gain matrices and the left eigenvector matrix of the high-order PI observers. These parameters included in this method offer all the design degrees of freedom, which can be further utilized to satisfy certain specified performances, such as disturbance decoupling, LTR and robustness. In addition, this method utilizes directly the original system data and involves manipulations only on n-dimensional matrices. An illustrative example shows the effect and simpleness of the proposed method.