D-Decomposition Synthesis of PD Controllers Applied to a Rotating System

In this work, a method of computing PD stabilizing gains for a given system is presented based on the D-decomposition technique, which requires the sole knowledge of frequency response functions (FRFs) of the system. By applying this method to a rotating system with electromagnetic actuators, it is demonstrated that the stability boundary locus in the plane of feedback gains can be easily plotted, and the most suitable gains can be found in order to minimize the resonant peak of the system. Experimental results for one and two disk rotors show the feasibility of not only controlling lateral shaft vibration and assuring stability, but also predicting the final vibration level achieved by the closed loop system. These results are obtained based solely on the input-output response information of the system as a whole, demonstrating that the technique applied to rotating systems can be an interesting alternative in comparison to traditional active vibration control strategies.