Design of the Digital Speed Control System for the Resonance System Based on the Pole Assignment Methods

Recently, motor drive systems are increasingly used in many industrial applications such as steel rolling mills, NC machines and robots. With the development of control theory and equipment, the system response has become faster and faster, while the stiffness of the system decreases because of miniaturization and weight reduction of the equipment. As the result, the system has to be treated as a resonance one in some cases. Several control methods such as with H∞ controller or pole assignment approach have been proposed, among which the resonance ratio control is a very effective method. In these methods, a disturbance observer is usually used to estimate the torsional torque. If there are errors in the outputs of the observer, it is difficult to obtain the desired control characteristics.In this paper, we propose a novel vibration suppression control method which needs no information about the load side variables, namely torsional torque and load speed. Based on the pole assignment approach, the poles of the system are selected as the gains of the load side variables are equal to zero simultaneously. The effectiveness of the proposed method has been verified by experiments.