Based On The GPC Researching The Rolling Central Control Algorithm

Predictive Control was born in the late 1970s in Europe and the United States in the field of industry, which is developed on the control of a computer algorithm, is a model based on the advanced control technology. With the research and development of adaptive control algorithm, and the development and application of the impulse response to the step response for the non-parametric model predictive control algorithm, Clarke and others raised the generalized model predictive control ( GPC) in 1984 which is based on controlled autoregressive moving average model of integration(CARIMA), and it used the method of multi-step forecast, the capability of anti-load disturbance, random noise, delay variation was significantly increased. And combining literacy and self-correction mechanism, it has a good performance of robustness. So it is widely taken attention by the academic and engineering in recent years, and has applied in industry. In this paper, we read a large number of literature reference about Rolling Machine, and had a simulation about the model, we make an effort to resolve the irreversible process issue and the realization of control without overshoot.The paper introduces D51-250 ring-rolling machine control system designing, and introduces the principle of Rolling Machine, the control algorithm remain used the algorithm of experience on the current domestic and international, even though it can achieve a certain degree of processing requirements, but in terms of advanced degrees, but also it can not reach a higher extent. Because the Rolling Machine is a nonlinear system, delayed, the time-varying characteristics of complex systems, the establishment of model is very complicated, it not only need to do a lot of experiments and calculation, but also it need have a strong theoretical foundation of nonlinear system modeling. The process of Rolling Machine needs non-overshoot, because its processing is a irreversible process. In the production process of irreversible, it is not permitted overshoot in the work-piece machining, because these processes is different from the process of temperature adjusting, the temperature adjusting allows the temperature is above or below the set value, but in certain process, if the actual value is more than the set value then it will be impossible to return, such as Rolling Ring calls for the outer diameter of D, but the processing gets to the D`> D, then the outer diameter of the work-piece can no longer meet the requirements of diameter D, it is only greater than the set value. And this is an irreversible process. Irreversible process widely exists in forging process, such as coiling machine and paper machine process.Secondly, we build a system modeling for the Rolling Machine Control System. Because of the special nature of the Rolling Machine system, it is very difficult to build, but if the accuracy of the algorithm use a kind of model is not very high, and to building a system of the model which contain the basic feature of the model is feasible, thus, some of the factor does not affect the system, we build a Rolling Machine model which neglected the factor. The model is based on adopted analytical method and system identification method combination of methods. Rolling Machine System model, taking into account the whole process of the major factors, can reflect a more complete about the matter of fact; can be used to design Rolling Machine open loop control system, optimal control system, adaptive control system, predictive control systems.Then, to solve the above problems, learn from the advanced research at domestic and abroad, we summed up a algorithm which can effectively inhibit overshoot, and the algorithm has much faster speed than the traditional experience algorithm, and has the GPC advantages:1) Anti-load disturbance, random noise and delayed variation was significantly improved;2) Combining literacy and self-correction mechanism, good performance robustness.The main approach is to use the model derived j step, then output the optimal value of y ( k + j), in the moment of k can get the compensation value for time t of the moment of k +1 by calculation, that is to say, to use the changed trend of incremental control to amend the variable which get from the Optimal control of open-loop control. Then we get the expression u(k+1) in the moment of k, we used the changed trend to amend the control incremental. This will be more precise tracking, and it played a very prominent role in inhibiting the overshoot.The whole system of Rolling Machine is a complex system, it's nonlinear, time-delay, and has many other characteristics, it needs a large number of experimental and calculated to build an accurate system model, and this system is a highly nonlinear systems, which requires strong nonlinear theory of knowledge. And the characteristics of predictive control is through a multi-step prediction, rolling optimization and feedback correction to achieve control strategy that will improve the object delay and order Robust , in other words, the Rolling Machine System does not require model has high precision, and it can achieve better control performance. So it can reasonably neglect many restrictive conditions for complex systems of Rolling Machine System modeling, and a simple interpretations of the model is established, which is by generalized predictive control to achieve control requirements and the no overshoot. Comparing with the original control method, it greatly improved the speed and accuracy of processing.This paper introduces the special nature of the Rolling Machine system, it integrated Rolling Machine and overshoot suppression algorithm of Generalized System Model predictive control together, and have researched the irreversible process of the control system. By citing overshoot suppression algorithm of GPC, it achieves precise control in irreversible process. This paper gave full proof not only in theory, but also has done a lot of simulations. The simulation results show the effectiveness of this strategy. And its industrial application laid the foundation for control of the scene. The simulation result and the Rolling Machine has been molding can prove that the strategy is feasible.