Parametric Identification for Second-Order Nonlinear Systems in Closed-Loop Operations

Abstract

A new scheme for identifying the parameters of second-order nonlinear systems, including those affine with the control input, is presented. First, a high-gain PD control is applied for the tracking of a prescribed reference trajectory, along which the regressor is persistently excited. Next, a parameter observer, modified from Huang (Huang, J. T., 2002, “An Adaptive Compensator for a Class of Linearly Parameterized Systems,” IEEE Trans. Automat. Control, 47 (3), pp. 483–486), is constructed to achieve the desired goals. Comparing to conventional methodologies, it is easier to implement for no acceleration signals or filtering of the system states being involved. Numerical examples are given in the final to demonstrate its effectiveness.