Two Reliable Methods for Estimating the Mechanical Parameters of a Rotating Three-Inertia System

Two methods for estimating the mechanical parameters of a rotating drive system that can be treated as a resonant 3-inertia system, are proposed. The accuracy of the estimation results is sufficient in order to design a state controller, which damps both resonances actively. Synopsis The mechanics of rotating drive systems normally consist of several inertias, which are joined together by elastic shafts. That is why they are resonant and only weakly damped. In order to control such systems, the mechanical parameters have to be known. In literature [ljung], [söderström], [isermann] several estimation methods are well known. The lowest resonant frequencies of known systems [wolff], [singer], [lorenz] are less than 100 Hz. Normally, those systems have been treated as 2-inertia systems. Especially in [singer], moreover one inertia has been known before and the positions both of the motor and the load have been evaluated. The resonant frequencies of modern high-dynamic drive systems are often much higher than 100 Hz. The dynamic range of modern control methods, e.g. DMTC (Direct Mean Torque Control) [flach], makes it possible to damp resonances of several 100 Hz, actively [pahlke]. Therefore, the mechanical parameters such systems have to be known accurately enough. Experimental set-ups