To improve the precision of the coiling temperature and the performance of the feedback control system with long pure time delay on hot strip mills, we analyzed the design process of the Dahlin algorithm in detail. Th...To improve the precision of the coiling temperature and the performance of the feedback control system with long pure time delay on hot strip mills, we analyzed the design process of the Dahlin algorithm in detail. The coiling temperature curves controlled by the PID algorithm and Dahlin algorithm were simulated and compared, which showed that the control precision with the Dahlin algorithm was higher than that with the PID algorithm. That was further verified by the production practice.展开更多
It is a fact that the feedback delay actually arises in digital control systems. It is necessary to modify the structure of digital control systems and develop new control algorithms, which is done in this paper. A gr...It is a fact that the feedback delay actually arises in digital control systems. It is necessary to modify the structure of digital control systems and develop new control algorithms, which is done in this paper. A great number of digital computer simulation experiments have shown the obvious advantage of the new algorithms.展开更多
Taking a single magnet levitation system as theobject, a nonlinear numerical model of the vehicle–guidewaycoupling system was established to study the levitationcontrol strategies. According to the similarity in dyna...Taking a single magnet levitation system as theobject, a nonlinear numerical model of the vehicle–guidewaycoupling system was established to study the levitationcontrol strategies. According to the similarity in dynamics,the single magnet-guideway coupling system was simplifiedinto a magnet-suspended track system, and the correspondinghardware-in-loop test rig was set up usingdSPACE. A full-state-feedback controller was developedusing the levitation gap signal and the current signal, andcontroller parameters were optimized by particle swarmalgorithm. The results from the simulation and the test rigshow that, the proposed control method can keep the systemstable by calculating the controller output with the fullstateinformation of the coupling system, Step responsesfrom the test rig show that the controller can stabilize thesystem within 0.15 s with a 2 % overshot, and performswell even in the condition of violent external disturbances.Unlike the linear quadratic optimal method, the particleswarm algorithm carries out the optimization with thenonlinear controlled object included, and its optimizedresults make the system responses much better.展开更多
This paper considers the H-infinity dynamic output feedback control for descriptor systems with delay in states. The controller is a descriptor system without delay. Several equivalent sufficient conditions for the ex...This paper considers the H-infinity dynamic output feedback control for descriptor systems with delay in states. The controller is a descriptor system without delay. Several equivalent sufficient conditions for the existence of one descriptor dynamic controller without impulsive models are given. Furthermore the explicit expression of the desired controller is obtained. The detailed design of the controller is presented using the cone complementarity linearization iterative algorithm and the LMI method. A ntumerical example is shown to illustrate the designed method.展开更多
An approach is proposed to design decentralized state feedback H ∞ suboptimal controllers for LTI interconnected large scale systems. The parametrization theorem of decentralized robust state feedback controllers is ...An approach is proposed to design decentralized state feedback H ∞ suboptimal controllers for LTI interconnected large scale systems. The parametrization theorem of decentralized robust state feedback controllers is developed in two steps and the design condition for the feedback gain is in the form of matrix inequalities. An iterative solution algorithm based on linear matrix inequality(LMI) techniques is proposed to obtain the decentralized feedback gain. The given examples are taken to show the application and the convergence of the algorithm.展开更多
In view of the problem that existing Media Access Control(MAC) protocols can not pro-vide real-time monitor on network conditions,this paper puts forward a new MAC protocol- Predict and Feedback MAC(PFMAC) which can p...In view of the problem that existing Media Access Control(MAC) protocols can not pro-vide real-time monitor on network conditions,this paper puts forward a new MAC protocol- Predict and Feedback MAC(PFMAC) which can predict the channel's congestion level reasonably.The dominant idea of the new scheme is to record the channel's busy or idle situation in the backoff stage by sending Sensor Nodes(SNs),and according to the congestion level every SN can change the contention window adaptively when send packets successfully to minimize collisions,saving energy and channel resources.The result of simulation shows that compared with other MAC protocols,the PFMAC protocol can improve network throughput and reduce energy consumption in high speed network en-vironment.展开更多
Greenhouse system (GHS) is the worldwide fastest growing phenomenon in agricultural sector. Greenhouse models are essential for improving control efficiencies. The Relative Gain Analysis (RGA) reveals that the GHS con...Greenhouse system (GHS) is the worldwide fastest growing phenomenon in agricultural sector. Greenhouse models are essential for improving control efficiencies. The Relative Gain Analysis (RGA) reveals that the GHS control is complex due to 1) high nonlinear interactions between the biological subsystem and the physical subsystem and 2) strong coupling between the process variables such as temperature and humidity. In this paper, a decoupled linear cooling model has been developed using a feedback-feed forward linearization technique. Further, based on the model developed Internal Model Control (IMC) based Proportional Integrator (PI) controller parameters are optimized using Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) to achieve minimum Integral Square Error (ISE). The closed loop control is carried out using the above control schemes for set-point change and disturbance rejection. Finally, closed loop servo and servo-regulatory responses of GHS are compared quantitatively as well as qualitatively. The results implicate that IMC based PI controller using PSO provides better performance than the IMC based PI controller using GA. Also, it is observed that the disturbance introduced in one loop will not affect the other loop due to feedback-feed forward linearization and decoupling. Such a control scheme used for GHS would result in better yield in production of crops such as tomato, lettuce and broccoli.展开更多
文摘To improve the precision of the coiling temperature and the performance of the feedback control system with long pure time delay on hot strip mills, we analyzed the design process of the Dahlin algorithm in detail. The coiling temperature curves controlled by the PID algorithm and Dahlin algorithm were simulated and compared, which showed that the control precision with the Dahlin algorithm was higher than that with the PID algorithm. That was further verified by the production practice.
文摘It is a fact that the feedback delay actually arises in digital control systems. It is necessary to modify the structure of digital control systems and develop new control algorithms, which is done in this paper. A great number of digital computer simulation experiments have shown the obvious advantage of the new algorithms.
文摘Taking a single magnet levitation system as theobject, a nonlinear numerical model of the vehicle–guidewaycoupling system was established to study the levitationcontrol strategies. According to the similarity in dynamics,the single magnet-guideway coupling system was simplifiedinto a magnet-suspended track system, and the correspondinghardware-in-loop test rig was set up usingdSPACE. A full-state-feedback controller was developedusing the levitation gap signal and the current signal, andcontroller parameters were optimized by particle swarmalgorithm. The results from the simulation and the test rigshow that, the proposed control method can keep the systemstable by calculating the controller output with the fullstateinformation of the coupling system, Step responsesfrom the test rig show that the controller can stabilize thesystem within 0.15 s with a 2 % overshot, and performswell even in the condition of violent external disturbances.Unlike the linear quadratic optimal method, the particleswarm algorithm carries out the optimization with thenonlinear controlled object included, and its optimizedresults make the system responses much better.
文摘This paper considers the H-infinity dynamic output feedback control for descriptor systems with delay in states. The controller is a descriptor system without delay. Several equivalent sufficient conditions for the existence of one descriptor dynamic controller without impulsive models are given. Furthermore the explicit expression of the desired controller is obtained. The detailed design of the controller is presented using the cone complementarity linearization iterative algorithm and the LMI method. A ntumerical example is shown to illustrate the designed method.
文摘An approach is proposed to design decentralized state feedback H ∞ suboptimal controllers for LTI interconnected large scale systems. The parametrization theorem of decentralized robust state feedback controllers is developed in two steps and the design condition for the feedback gain is in the form of matrix inequalities. An iterative solution algorithm based on linear matrix inequality(LMI) techniques is proposed to obtain the decentralized feedback gain. The given examples are taken to show the application and the convergence of the algorithm.
基金Supported by the 948 Project (2012-4-21)the Ph.D.Programs Foundation of Ministry of Education of China(20100062120008)the Scientific Research Fund of Heilongjiang Provincial Education Department(11553022)
文摘In view of the problem that existing Media Access Control(MAC) protocols can not pro-vide real-time monitor on network conditions,this paper puts forward a new MAC protocol- Predict and Feedback MAC(PFMAC) which can predict the channel's congestion level reasonably.The dominant idea of the new scheme is to record the channel's busy or idle situation in the backoff stage by sending Sensor Nodes(SNs),and according to the congestion level every SN can change the contention window adaptively when send packets successfully to minimize collisions,saving energy and channel resources.The result of simulation shows that compared with other MAC protocols,the PFMAC protocol can improve network throughput and reduce energy consumption in high speed network en-vironment.
文摘Greenhouse system (GHS) is the worldwide fastest growing phenomenon in agricultural sector. Greenhouse models are essential for improving control efficiencies. The Relative Gain Analysis (RGA) reveals that the GHS control is complex due to 1) high nonlinear interactions between the biological subsystem and the physical subsystem and 2) strong coupling between the process variables such as temperature and humidity. In this paper, a decoupled linear cooling model has been developed using a feedback-feed forward linearization technique. Further, based on the model developed Internal Model Control (IMC) based Proportional Integrator (PI) controller parameters are optimized using Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) to achieve minimum Integral Square Error (ISE). The closed loop control is carried out using the above control schemes for set-point change and disturbance rejection. Finally, closed loop servo and servo-regulatory responses of GHS are compared quantitatively as well as qualitatively. The results implicate that IMC based PI controller using PSO provides better performance than the IMC based PI controller using GA. Also, it is observed that the disturbance introduced in one loop will not affect the other loop due to feedback-feed forward linearization and decoupling. Such a control scheme used for GHS would result in better yield in production of crops such as tomato, lettuce and broccoli.
