Tan Shubin

Research on Mill Modulus Control of Strip Rolling AGC Systems

Recently, the accuracy of hot strip gauge is strictly demanded, and the strip thickness becomes the most important quality in hot strip rolling. In order to improve the quality of the hot strip gage and to reduce the strip thickness deviation, the automatic gauge control (AGC) system now is widely used in modern hot strip mills. Mill modulus control (MMC) is one of important methods in AGC system for strip rolling mills. Control theories and models related to MMC were studied deeply in this paper. Its ability to eliminate strip thickness deviation, rolling force noise and roller eccentricity disturbances were simulated respectively based on different virtual mill modulus with MATLAB. As a result, how to get a better control effect was analyzed and confirmed.

On the simulation application for teaching practice in the course of motion control system

Computer simulation technology, which with application of software platforms likes FLASH, MultiSim and MATLAB/SIMULINK, was introduced into teaching progress, considering the existing teaching situation and features of the motion control system. By combining the theory explaining and simulation results together, it become more easy to reveal and exposit the essence of the lecture, more specific and straightforward to make the teaching process become, moreover, it help students to understand abstract theory and key segments of the motion control system better and stimulate their learning positivity, thereby achieve a outstanding teaching result.

Design of state feedback H∞ controller for multivariable rolling process based on state space model

For the rolling system, it should be a multi-variable, strong disturbance and coupled nonlinear system. As the precondition of ensuring the precision of strip thickness, it is necessary to ensure that the system is robust. The controller should be able to suppress the disturbance of the system and remain the system stable under the uncertain parameters. Taking into account the complexity of the system, this paper established a linear state space model of the hydraulic roller system, main drive system and rolling process system for the deeper study on the relationship between the variables in the rolling process. Considering the complexity of the external disturbance, this paper choose the H∞ control strategy. MATLAB is used to solve the linear matrix inequalities. By selecting the appropriate performance index, the state feedback controller could be found. The simulation result shows that the H∞ state feedback control system has the better robustness and performance index.

Performance assessment of cascade control systems based on LQG benchmark

Given that the LQG benchmark is closer to the actual production, performance assessment of cascade control system based on LQG benchmark has been proposed. The joint input and output subspace identification algorithm was used to estimate the process model, noise transfer function, the inner loop controller and the outer loop controller. And three possible cases could be considered to evaluate cascade control systems. First, none of the inner and outer controllers were known and the goal was to design both controllers to get the global optimum. Second, the outer controller was considered to be fixed and one was looking for the best achievable performance by designing the inner controller. Third, the inner controller was considered to be fixed and one was looking for the best achievable performance by designing the outer controller. These three scenarios were used to evaluate the performance of the global, the inner controller performance and the outer controller. According to the simulation results, performance assessment of cascade control systems based on the LQG benchmark not only get the global performance of the system, but also show how much improvement may be achieved by designing inner and outer controllers.

Performance assessment of single loop control systems with LQG benchmark

In the industrial process, not only is the output of the system expected to achieve the minimum variance, but also the variance of process input fluctuates in a certain range. However, minimum variance benchmark can meet the former but not the requirements of latter because of strong control effect. Therefore, subspace identification with combined input and output is utilized in this paper to identify single loop control systems, which obtains the process and the noise model, firstly. Then, the performance of the control system is assessed with LQG benchmark combining the control input and output synthetically, and the specific implementation steps are concluded systematically. Finally, the proposed method is verified effective through simulations.

Research on the gap setting model of short stroke control system in hot edge rolling

According to the phenomenon of width losing in slab end, the spread of slab end including edger pressing, dog bone spread and nature spread, short stroke control was used in 2300 hot strip roughing mill. The parabola model has been proposed in this article, because of the disadvantage of broken line used by 2300 hot strip mill, and the online implementation plan of parabola model has been given. The broken line model and the parabola model have been contrasted by simulation, which indicates that the control effect of parabola model is better than the broken line model.

Research and analysis on mathematical model of looper control in hot strip rolling mills

The accuracy of looper length calculation is highly significant in the looper control system of hot strip rolling mills. This paper described the precise calculation formula, the isosceles triangle approximate calculation formula and Taylor series expansion approximate calculation formula used in looper length calculation. The accuracy of these three formulas is compared in 1580 mm, 1700 mm and 2050 mm hot strip rolling mill. In conclusion, the isosceles triangle approximate calculation formula is proved to be with the advantage of high accuracy and simple models.