Automatic width control is a key issue in hot strip rolling process. The edge rolling has been widely used in the roughing stand of hot strip mill to control the width of the slab. However, the edge rolling and conseq...Automatic width control is a key issue in hot strip rolling process. The edge rolling has been widely used in the roughing stand of hot strip mill to control the width of the slab. However, the edge rolling and consequent hori- zontal rolling will cause a significant width change in the head part and tail part of the slab, which have to be trimmed before the finishing stands. Based on the width reduction deformation curve of the head and tail along the longitudinal direction of slab, the short stroke control （SSC） technology has been developed to overcome this problem. The finite element method has been used to simulate the unsteady edge rolling process. Three short stroke control curves have been compared in order to obtain the best width control result. The optimized short stroke control curve has been ap- plied to the automatic width control system of industrial hot rolling mill, and good performance is obtained.展开更多
The highly nonlinear behavior of the system limits the performance of classical linear proportional and integral （PI） controllers used for hot rolling. An active disturbance rejection controller is proposed in this ...The highly nonlinear behavior of the system limits the performance of classical linear proportional and integral （PI） controllers used for hot rolling. An active disturbance rejection controller is proposed in this paper to deal with the nonlinear problem of hydraulic servo system in order to preserve last response and small overshoot of control system. The active disturbance rejection （ADR） controller is composed of nonlinear tracking differentiator （TD）, extended state observer （ESO） and nonlinear feedback （NF） law. An example of the hydraulic edger system case study is investigated to show the effectiveness and robustness of the proposed nonlinear controller, especially, in the circumstance of foreign disturbance and working condition variation, compared with classic PI controller.展开更多
According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill t...According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill train.On the basis of improving width range of continuous casting of slab,we obtained a good result of greatly increasing the yield of slab→coil is achieved.展开更多
This paper presents a width controller,a dead time controller,a discontinuous current mode（DCM） controller and a frequency skipping modulation（FSM） controller for a high frequency high efficiency buck DC-DC conver...This paper presents a width controller,a dead time controller,a discontinuous current mode（DCM） controller and a frequency skipping modulation（FSM） controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range,especially at high switching frequency,the dead time controller and width controller are applied to enhance the high load efficiency,while the DCM controller and FSM controller are proposed to increase the light load efficiency.The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35μm CMOS process,and the measured results show that the efficiency of the buck DC-DC converter is above 80%over a wide load current range from 8 to 570 mA,and the peak efficiency is 86%at 10 MHz switching frequency.展开更多
In this paper, the weld pool shape control by intelligent strategy was studied. A neuron self-learning PSD controller for backside width of weld pool in pulsed GTAW with wire filler was designed. The PSD control arith...In this paper, the weld pool shape control by intelligent strategy was studied. A neuron self-learning PSD controller for backside width of weld pool in pulsed GTAW with wire filler was designed. The PSD control arithmetic was analyzed, simulating experiment by MATLAB software was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were successfully implemented. The study results show that the neuron self-learning PSD control method can attain a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model.展开更多
Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation f...Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.展开更多
The surface dielectric barrier discharge （SDBD） plasma actuator has shown great promise as an aerodynamic flow control device. In this paper, the encapsulated electrode width of a SDBD actuator is changed to study t...The surface dielectric barrier discharge （SDBD） plasma actuator has shown great promise as an aerodynamic flow control device. In this paper, the encapsulated electrode width of a SDBD actuator is changed to study the airflow acceleration behavior. The effects of encapsulated electrode width on the actuator performance are experimentally investigated by measuring the dielectric layer surface potential, time-averaged ionic wind velocity and thrust force. Experimental results show that the airflow velocity and thrust force increase with the encapsulated electrode width. The results can be attributed to the distinct plasma distribution at different encapsulated electrode widths.展开更多
The weld pool shape control by intelligent strategy was studied. In order to improve the ability of self-learning and self-adaptation of the ordinary fuzzy control, a self-learning fuzzy neural network controller (FNN...The weld pool shape control by intelligent strategy was studied. In order to improve the ability of self-learning and self-adaptation of the ordinary fuzzy control, a self-learning fuzzy neural network controller (FNNC) for backside width of weld pool in pulsed gas tungsten arc welding (GTAW) with wire filler was designed. In FNNC, the fuzzy system was expressed by an equivalence neural network, the membership functions and inference rulers were decided through the learning of the neural network. Then, the FNNC control arithmetic was analyzed, simulating experiment was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were implemented. The maximum error between the real value and the given one was 0.39mm, the mean error was 0.014mm, and the root-mean-square was 0.14mm. The real backside width was maintained around the given value. The results show that the self-learning fuzzy neural network control strategy can achieve a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model.展开更多
The attitude control problem of the kinetic kill vehicle is studied in this work. A new mathematical model of the kinetic kill vehicle is proposed, the linear quadratic regulator technique is used to design the optima...The attitude control problem of the kinetic kill vehicle is studied in this work. A new mathematical model of the kinetic kill vehicle is proposed, the linear quadratic regulator technique is used to design the optimal attitude controller, and the pulse-width pulse-frequency modulator is used to shape the continuous control command to pulse or on-off signals to meet the requirements of the reaction thrusters. The methods to select the appropriate parameters of pulse-width pulse-frequency are presented in detail. Numerical simulations show that the performance of the LQR/PWPF approach can achieve good control performance such as pseudo-linear operation, high accuracy, and fast enough tracking speed.展开更多
Two-dimensional/one-dimensional(2D/1D)heterostructures as a new type of heterostructure have been studied for their unusual properties and promising applications in electronic and optoelectronic devices.However,the st...Two-dimensional/one-dimensional(2D/1D)heterostructures as a new type of heterostructure have been studied for their unusual properties and promising applications in electronic and optoelectronic devices.However,the studies of 2D/1D heterostructures are mainly focused on vertical heterostructures,such as MoS_(2) nanosheet-carbon nanotubes.The research on lateral 2D/1D heterostructures with a tunable width of 1D material is still scarce.In this study,bidirectional flow chemical vapor deposition(CVD)was used to accurately control the width of the WS_(2)/WSe2(WS_(2)/MoS_(2))heterostructures by controlling reacting time.WSe2 and MoS_(2) with different widths were epitaxially grown at the edge of WS_(2),respectively.Optical microscope,atomic force microscope(AFM),and scanning electron microscope(SEM)images show the morphology and width of the heterostructures.These results show that the width of the heterostructures can be as low as 10 nm by using this method.The interface of the heterostructure is clear and smooth,which is suitable for application.This report offers a new method for the growth of 1D nanowires,and lays the foundation for the future study of the physical and chemical properties of 2D/1D lateral heterostructures.展开更多
基金Item Sponsored by National Science and Technology Support Programfor 11th Five-Year Plan of China (2006BAE03A13)International Cooperation Research Project of Shanxi Province (2009081013)
文摘Automatic width control is a key issue in hot strip rolling process. The edge rolling has been widely used in the roughing stand of hot strip mill to control the width of the slab. However, the edge rolling and consequent hori- zontal rolling will cause a significant width change in the head part and tail part of the slab, which have to be trimmed before the finishing stands. Based on the width reduction deformation curve of the head and tail along the longitudinal direction of slab, the short stroke control （SSC） technology has been developed to overcome this problem. The finite element method has been used to simulate the unsteady edge rolling process. Three short stroke control curves have been compared in order to obtain the best width control result. The optimized short stroke control curve has been ap- plied to the automatic width control system of industrial hot rolling mill, and good performance is obtained.
基金Project supported by the National Basic Research Program (973) of China (No. 2006CB705400)the National Natural Science Foun- dation of China (No. 50575200)
文摘The highly nonlinear behavior of the system limits the performance of classical linear proportional and integral （PI） controllers used for hot rolling. An active disturbance rejection controller is proposed in this paper to deal with the nonlinear problem of hydraulic servo system in order to preserve last response and small overshoot of control system. The active disturbance rejection （ADR） controller is composed of nonlinear tracking differentiator （TD）, extended state observer （ESO） and nonlinear feedback （NF） law. An example of the hydraulic edger system case study is investigated to show the effectiveness and robustness of the proposed nonlinear controller, especially, in the circumstance of foreign disturbance and working condition variation, compared with classic PI controller.
文摘According to technological requirement of hot charge rolling and hot direct rolling,in this paper,we investigated the technology of the width control rolling in the rougher mills of hot strip continuous rolling mill train.On the basis of improving width range of continuous casting of slab,we obtained a good result of greatly increasing the yield of slab→coil is achieved.
基金Project supported by the National Natural Science Foundation of China(No.60676013).
文摘This paper presents a width controller,a dead time controller,a discontinuous current mode（DCM） controller and a frequency skipping modulation（FSM） controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range,especially at high switching frequency,the dead time controller and width controller are applied to enhance the high load efficiency,while the DCM controller and FSM controller are proposed to increase the light load efficiency.The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35μm CMOS process,and the measured results show that the efficiency of the buck DC-DC converter is above 80%over a wide load current range from 8 to 570 mA,and the peak efficiency is 86%at 10 MHz switching frequency.
文摘In this paper, the weld pool shape control by intelligent strategy was studied. A neuron self-learning PSD controller for backside width of weld pool in pulsed GTAW with wire filler was designed. The PSD control arithmetic was analyzed, simulating experiment by MATLAB software was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were successfully implemented. The study results show that the neuron self-learning PSD control method can attain a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.N120407007)
文摘Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.
基金supported by National Natural Science Foundation of China(No.11175037)National Natural Science Foundation for Young Scientists of China(No.11305017)Special Fund for Theoretical Physics(No.11247239)
文摘The surface dielectric barrier discharge （SDBD） plasma actuator has shown great promise as an aerodynamic flow control device. In this paper, the encapsulated electrode width of a SDBD actuator is changed to study the airflow acceleration behavior. The effects of encapsulated electrode width on the actuator performance are experimentally investigated by measuring the dielectric layer surface potential, time-averaged ionic wind velocity and thrust force. Experimental results show that the airflow velocity and thrust force increase with the encapsulated electrode width. The results can be attributed to the distinct plasma distribution at different encapsulated electrode widths.
文摘The weld pool shape control by intelligent strategy was studied. In order to improve the ability of self-learning and self-adaptation of the ordinary fuzzy control, a self-learning fuzzy neural network controller (FNNC) for backside width of weld pool in pulsed gas tungsten arc welding (GTAW) with wire filler was designed. In FNNC, the fuzzy system was expressed by an equivalence neural network, the membership functions and inference rulers were decided through the learning of the neural network. Then, the FNNC control arithmetic was analyzed, simulating experiment was done, and the validating experiments on varied heat sink workpiece and varied gap workpiece were implemented. The maximum error between the real value and the given one was 0.39mm, the mean error was 0.014mm, and the root-mean-square was 0.14mm. The real backside width was maintained around the given value. The results show that the self-learning fuzzy neural network control strategy can achieve a perfect control effect under different set values and conditions, and is suitable for the welding process with the varied structure and coefficients of control model.
文摘The attitude control problem of the kinetic kill vehicle is studied in this work. A new mathematical model of the kinetic kill vehicle is proposed, the linear quadratic regulator technique is used to design the optimal attitude controller, and the pulse-width pulse-frequency modulator is used to shape the continuous control command to pulse or on-off signals to meet the requirements of the reaction thrusters. The methods to select the appropriate parameters of pulse-width pulse-frequency are presented in detail. Numerical simulations show that the performance of the LQR/PWPF approach can achieve good control performance such as pseudo-linear operation, high accuracy, and fast enough tracking speed.
基金the support from National Natural Science Foundation of China(No.51872086)the Hunan Key Laboratory of Two-Dimensional Materials(Grant No.2018TP1010)the Innovative Research Groups of Hunan Province(Grant No.2020JJ1001)for the work conducted at Hunan University.
文摘Two-dimensional/one-dimensional(2D/1D)heterostructures as a new type of heterostructure have been studied for their unusual properties and promising applications in electronic and optoelectronic devices.However,the studies of 2D/1D heterostructures are mainly focused on vertical heterostructures,such as MoS_(2) nanosheet-carbon nanotubes.The research on lateral 2D/1D heterostructures with a tunable width of 1D material is still scarce.In this study,bidirectional flow chemical vapor deposition(CVD)was used to accurately control the width of the WS_(2)/WSe2(WS_(2)/MoS_(2))heterostructures by controlling reacting time.WSe2 and MoS_(2) with different widths were epitaxially grown at the edge of WS_(2),respectively.Optical microscope,atomic force microscope(AFM),and scanning electron microscope(SEM)images show the morphology and width of the heterostructures.These results show that the width of the heterostructures can be as low as 10 nm by using this method.The interface of the heterostructure is clear and smooth,which is suitable for application.This report offers a new method for the growth of 1D nanowires,and lays the foundation for the future study of the physical and chemical properties of 2D/1D lateral heterostructures.
