Experimental nonlinear identification of a two mass system

The paper presents nonlinear modeling and on-line identification of a two mass mechanical system driven by a DC motor together with real-time experiments made. The paper also describes how to obtain a simpler identification routine for the nonlinear systems. Linear and nonlinear models for the system are obtained for identification purposes and the major nonlinearities in the system such as the Coulomb friction and the dead-zone are investigated and integrated in the nonlinear model. Hammerstein nonlinear system approach is used for the identification of the nonlinear system model. On-line identification of the linear and nonlinear system models is performed using the Recursive Least Squares (RLS) method. Results of the real-time experiments are graphically and numerically presented, and advantages of the nonlinear identification approach are definitely revealed.