A new identification method of linear system based on the feature of step response curve

The purpose of this paper is to obtain the transfer function of the linear time-invariant system from the feature of step response curve. According to the theory that the typical first-order and second-order component can comprise high order linear system in parallel form, we should firstly sum up laws of various parameters´ aspect on the shape of the curve; Secondly, we can use these laws to adjust the value of various parameters in typical component, so as to make the parallel estimation model´s step response curve get close to the actual system´s step response curve, and we will obtain the mathematical model if the two curves are closed enough. In order to validate the feasibility and correctness of the algorithm, we develop an identification software with the help of MATLAB Graphical User Interface (GUI). The simulation results show that this method is reliable with high accuracy.