| The accuracy of the strip gauge is one of the most important quality targets for board or strip products. With the development of social economy, the quality of board or strip products is required more and more strictly. It is necessary to research on gauge control system and it is significant to apply modern control theory to gauge control system of rolling mill.In this paper after the control principle of rolling mill and gauge control technology has been studied, the conception of roll-gap closed loop rolling mill stifmess is introduced for rolling mill of inner roll-gap control and dynamic math model of inner roll-gap gauge control system is established, which provides theory basis for rolling mill of inner roll-gap control.Due to the influence of these factors such as mechanism system, control system of rolling mill and the gauge variation of materiel, also including the difference of dynamic characteristic of rolling mill two-side pressing framework, the system has much uncertainty. It is difficult to attain high control precision and performance requirement with common control methods. To solve these problems, the method of applying robust control into gauge control system is introduced because robust control is often used in model uncertainty and exterior disturbance uncertainty condition.According to the traits of time delay in gauge control system, Smith predictor is adopted to overcome measuring delay. In this paper inner model design method is adopted and Smith predictor control system is designed from inner model point of view. If closed loop transfer function of position inner loop is thought as typical two-order system, H2 robust control based on Smith predictor is adopted to solve the variation of long-time delay and pressing efficiency of thickness measuring. Smith predictor model is real-time correction in order to solve time delay variation with rolling speed, but deviation still exists in corrected model. In this paper Simulation research is done and stability is analyzed. |
