Controlling the looper height and strip tension is important in hot strip mills because these variables affect both the strip quality and strip threading. Many researchers have proposed and applied a variety of contro...Controlling the looper height and strip tension is important in hot strip mills because these variables affect both the strip quality and strip threading. Many researchers have proposed and applied a variety of control schemes for this problem, but the increasingly strict market demand for strip quality requires further improvements. This work describes a dynamic matrix predictive control(DMC) strategy that realizes the optimal control of a hydraulic looper multivariable system. Simulation experiments for a traditional controller and the proposed DMC controller were conducted using MATLAB/Simulink software. The simulation results show that both controllers acquire good control effects with model matching. However, when the model is mismatched, the traditional controller produces an overshoot of 32.4% and a rising time of up to 2120.2 ms, which is unacceptable in a hydraulic looper system. The DMC controller restricts the overshoot to less than 0.08%, and the rising time is less than 48.6 ms in all cases.展开更多
The looper drive mechanism is a main moving part in the blind stitching machine, which is aspatial 5 bar RRRSR linkage. In this paper, a dynamic analysis of the looper drive mechanism is made by means of the ma-trix m...The looper drive mechanism is a main moving part in the blind stitching machine, which is aspatial 5 bar RRRSR linkage. In this paper, a dynamic analysis of the looper drive mechanism is made by means of the ma-trix method. Two methods are adopted in the calculation of the shaking force and shaking moment, one isdone by the constraint reaction of the flame-connected kinematic parts; the other is the inertialforces of all moving links.展开更多
To solve the coupling relationship between the strip automatic gauge control and the looper control in traditional control strategy of tandem hot rolling,a distributed model predictive control(DMPC)strategy for the ta...To solve the coupling relationship between the strip automatic gauge control and the looper control in traditional control strategy of tandem hot rolling,a distributed model predictive control(DMPC)strategy for the tandem hot rolling was explored,and a series of simulation experiments were carried out.Firstly,based on the state space analysis method,the multivariable dynamic transition process of hot strip rolling was studied,and the state space model of a gauge-looper integrated system in tandem hot rolling was established.Secondly,DMPC strategy based on neighborhood optimization was proposed,which fully considered the coupling relationship in this integrated system.Finally,a series of experiments simulating disturbances and emergency situations were completed with actual rolling data.The experimental results showed that the proposed DMPC control strategy had better performance compared with the traditional proportional-integral control and centralized model predictive control,which is applicable for the gauge-looper integrated system.展开更多
An innovative sliding mode controller for looper and tension control in hot strip finishing mills was developed based on approximately linearized model. Firstly, a fictitious controller of the reduced order subsystem ...An innovative sliding mode controller for looper and tension control in hot strip finishing mills was developed based on approximately linearized model. Firstly, a fictitious controller of the reduced order subsystem was designed according to desired dynamics, by which, the angle and tension loops were decoupled on the sliding manifold. Then, a sliding mode controller was used to validate finite time convergence of the state vector to the manifold which guaranteed the stability and performances of the overall system. This solution was considered owing to its well- known robustness and simplicity characteristics concerning disturbances and unmodelled dynamics. Simulation results showed the effectiveness of the proposed controller compared with conventional ones.展开更多
High control performances cannot be obtained by most of the existing looper-tension control approaches through only considering controller designs based on continuous time models, which cannot meet the requirements of...High control performances cannot be obtained by most of the existing looper-tension control approaches through only considering controller designs based on continuous time models, which cannot meet the requirements of modern computer control systems with high control accuracy. In order to solve the above problems, a state feedback H∞ control method based on a discrete-time model for looper-tension control systems in hot rolling mills is presen- ted. The considered system is approximated by a discrete-time loope∞tension control system model. Based on a Lya- punov functional method, a state feedback H∞ control law is developed which makes the closed-loop system asymp totically stable with guaranteed H∞ performance. The controller gains are obtained by solving a set of linear matrix inequalities （LMIs）. In contrast to the existing results, the proposed approach can obtain good H∞ performance and effectively reduce external disturbances. The strip tension is also less affected by the change of looper angel, so good control performances can be obtained. Moreover, this control scheme is easy to implement, and can be applied to other linear systems. A simulation example with practical parameters is provided to illustrate the effectiveness of the developed method.展开更多
The development of an innovative H∞ controller for looper and tension control in hot strip finishing mills is traced based on approximately linearized model. This solution has been considered thanks to its well- know...The development of an innovative H∞ controller for looper and tension control in hot strip finishing mills is traced based on approximately linearized model. This solution has been considered thanks to its well- known robustness and simplicity characteristics concerning disturbances' attenuation. The controller is designed based on an optimal problem with linear matrix inequality (LMI) constraints, and the problem is solved by the mincx function of Matlab LMI Toolbox. Simulation results show the effectiveness of the proposed controller compared with conventional ones.展开更多
A guaranteed cost sliding mode control(SMC)algorithm is investigated to further improve the control accuracy of looper-tension systems in hot strip finishing mills.First,a global sliding mode surface function is desig...A guaranteed cost sliding mode control(SMC)algorithm is investigated to further improve the control accuracy of looper-tension systems in hot strip finishing mills.First,a global sliding mode surface function is designed by linear matrix inequalities and guaranteed cost technique,which can force the system states into switching region initially,and can guarantee the system robustness with a good performance during the whole control process.Then,a novel reaching law is designed,which can satisfy the sliding mode reaching conditions.Simulation results demonstrate that the proposed control scheme has good stability and robustness comparing with traditional SMC.The designed controller can regulate the strip tension and looper angle to ensure better performance,which is very suitable for complex looper systems.展开更多
基金Project(N160704004)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(20131033)supported by the Ph D Start-up Fund of Natural Science Foundation of Liaoning Province,China
文摘Controlling the looper height and strip tension is important in hot strip mills because these variables affect both the strip quality and strip threading. Many researchers have proposed and applied a variety of control schemes for this problem, but the increasingly strict market demand for strip quality requires further improvements. This work describes a dynamic matrix predictive control(DMC) strategy that realizes the optimal control of a hydraulic looper multivariable system. Simulation experiments for a traditional controller and the proposed DMC controller were conducted using MATLAB/Simulink software. The simulation results show that both controllers acquire good control effects with model matching. However, when the model is mismatched, the traditional controller produces an overshoot of 32.4% and a rising time of up to 2120.2 ms, which is unacceptable in a hydraulic looper system. The DMC controller restricts the overshoot to less than 0.08%, and the rising time is less than 48.6 ms in all cases.
文摘The looper drive mechanism is a main moving part in the blind stitching machine, which is aspatial 5 bar RRRSR linkage. In this paper, a dynamic analysis of the looper drive mechanism is made by means of the ma-trix method. Two methods are adopted in the calculation of the shaking force and shaking moment, one isdone by the constraint reaction of the flame-connected kinematic parts; the other is the inertialforces of all moving links.
基金This work was supported by the National Key R&D Program of China(Grant Nos.2018YFB1308700)the National Natural Science Foundation of China(Grant Nos.U21A20117 and 52074085+1 种基金the Fundamental Research Funds for the Central Univer-sities(Grant No.N2004010)the Liaoning Revitalization Talents651 Program(XLYC1907065).
文摘To solve the coupling relationship between the strip automatic gauge control and the looper control in traditional control strategy of tandem hot rolling,a distributed model predictive control(DMPC)strategy for the tandem hot rolling was explored,and a series of simulation experiments were carried out.Firstly,based on the state space analysis method,the multivariable dynamic transition process of hot strip rolling was studied,and the state space model of a gauge-looper integrated system in tandem hot rolling was established.Secondly,DMPC strategy based on neighborhood optimization was proposed,which fully considered the coupling relationship in this integrated system.Finally,a series of experiments simulating disturbances and emergency situations were completed with actual rolling data.The experimental results showed that the proposed DMPC control strategy had better performance compared with the traditional proportional-integral control and centralized model predictive control,which is applicable for the gauge-looper integrated system.
基金Sponsored by National Natural Science Foundation of China(60934007,61174059)Program for New Century Excellent Talents of China(NCET-08-0359)Shanghai Rising-Star Tracking Program of China(11QH1401300)
文摘An innovative sliding mode controller for looper and tension control in hot strip finishing mills was developed based on approximately linearized model. Firstly, a fictitious controller of the reduced order subsystem was designed according to desired dynamics, by which, the angle and tension loops were decoupled on the sliding manifold. Then, a sliding mode controller was used to validate finite time convergence of the state vector to the manifold which guaranteed the stability and performances of the overall system. This solution was considered owing to its well- known robustness and simplicity characteristics concerning disturbances and unmodelled dynamics. Simulation results showed the effectiveness of the proposed controller compared with conventional ones.
基金Item Sponsored by National Natural Science Foundation of China(51374082)National High-Tech Research and Development Program(863Program)of China(2012AA050215)China Iron and Steel Research Foundation(12ZD0850A)
文摘High control performances cannot be obtained by most of the existing looper-tension control approaches through only considering controller designs based on continuous time models, which cannot meet the requirements of modern computer control systems with high control accuracy. In order to solve the above problems, a state feedback H∞ control method based on a discrete-time model for looper-tension control systems in hot rolling mills is presen- ted. The considered system is approximated by a discrete-time loope∞tension control system model. Based on a Lya- punov functional method, a state feedback H∞ control law is developed which makes the closed-loop system asymp totically stable with guaranteed H∞ performance. The controller gains are obtained by solving a set of linear matrix inequalities （LMIs）. In contrast to the existing results, the proposed approach can obtain good H∞ performance and effectively reduce external disturbances. The strip tension is also less affected by the change of looper angel, so good control performances can be obtained. Moreover, this control scheme is easy to implement, and can be applied to other linear systems. A simulation example with practical parameters is provided to illustrate the effectiveness of the developed method.
基金the National Natural Science Foundation of China (No. 60934007)the Program for New Century Excellent Talents (No. NCET-08-0359)the Shanghai Rising-Star Tracking Program(No. 11QH1401300)
文摘The development of an innovative H∞ controller for looper and tension control in hot strip finishing mills is traced based on approximately linearized model. This solution has been considered thanks to its well- known robustness and simplicity characteristics concerning disturbances' attenuation. The controller is designed based on an optimal problem with linear matrix inequality (LMI) constraints, and the problem is solved by the mincx function of Matlab LMI Toolbox. Simulation results show the effectiveness of the proposed controller compared with conventional ones.
基金supported by the Science and Technology Project of Hebei Province[grant number 15211028]the Technology Support Project of Northeastern University at Qinhuangdao[grant number XNK201604],[grant number XNK201407]+2 种基金the National Natural Science Foundation of China[grant number 61403069]the Natural Science Foundation of Hebei Province[grant number F2014501055]the Program of Science and Technology Research of Hebei University[grant number ZD20132003].
文摘A guaranteed cost sliding mode control(SMC)algorithm is investigated to further improve the control accuracy of looper-tension systems in hot strip finishing mills.First,a global sliding mode surface function is designed by linear matrix inequalities and guaranteed cost technique,which can force the system states into switching region initially,and can guarantee the system robustness with a good performance during the whole control process.Then,a novel reaching law is designed,which can satisfy the sliding mode reaching conditions.Simulation results demonstrate that the proposed control scheme has good stability and robustness comparing with traditional SMC.The designed controller can regulate the strip tension and looper angle to ensure better performance,which is very suitable for complex looper systems.
