Speed Control of Two-mass System Based on H<sup>∞</sup> Control Theory

摘要

In the industrial motor drive systems such as industrial plants and industrial robots, a torsional vibration is often generated because of the elastic elements in torque transmission. This vibration makes it difficult to achieve quick responses of speed and may result in damage to the plant. Such system is simply modelled as a two-mass mechanical system.In this paper, H∞ control theory is applied to design the speed controller for the two-mass system. This controller determines the closed-loop characteristics such as the suppression of torsional vibration and the rejection of torque disturbance. Moreover, the two-degrees-of-freedom controller, which includes the above H∞ controller, is designed in order to improve the tracking characteristics for the commanded speed. In the TDOF system, the performances of the disturbance rejection and the tracking can be designed independently. The control performances are examined in detail by the computer simulations. As the designed controller is usually high order controller, the order reduction of controller is also discussed for the practical applications. From several examinations, it is clarified that the proposed speed control system is useful for the two-mass system.