Parametric identification of non-linear systems

In this paper a new identification method is proposed for a class of non-linear systems. A linearized second order process model with time delay for the nonlinear system is identified using a relay test. Using some transformation it has been shown that the linearized process model faithfully represents the non-linear system. Lyapunov stability criterion is used to check the stability of the linearized model. To show effectiveness of the identification method, parameters of a PID controller have been found based on loop phase margin and gain margin criteria. Simulation results of a non-linear system show usefulness of the proposed identification method.