The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method na...The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method named plasma-based atom-selective etching(PASE)is proposed to achieve the highly efficient,atomic-scale,and damage-free polishing of β-Ga_(2)O_(3).The plasma is excited through the inductive coupling principle and carbon tetrafluoride is utilized as the main reaction gas to etch β-Ga_(2)O_(3).The core of PASE polishing of β-Ga_(2)O_(3)is the remarkable lateral etching effect,which is ensured by both the intrinsic property of the surface and the extrinsic temperature condition.As revealed by density functional theory-based calculations,the intrinsic difference in the etching energy barrier of atoms at the step edge(2.36 eV)and in the terrace plane(4.37 eV)determines their difference in the etching rate,and their etching rate difference can be greatly enlarged by increasing the extrinsic temperature.The polishing of β-Ga_(2)O_(3)based on the lateral etching effect is further verified in the etching experiments.The Sa roughness of β-Ga_(2)O_(3)(001)substrate is reduced from 14.8 nm to 0.057 nm within 120 s,and the corresponding material removal rate reaches up to 20.96μm·min^(−1).The polished β-Ga_(2)O_(3)displays significantly improved crystalline quality and photoluminescence intensity,and the polishing effect of PASE is independent of the crystal face of β-Ga_(2)O_(3).In addition,the competition between chemical etching and physical reconstruction,which is determined by temperature and greatly affects the surface state of β-Ga_(2)O_(3),is deeply studied for the first time.These findings not only demonstrate the high-efficiency and high-quality polishing of β-Ga_(2)O_(3)via atmospheric plasma etching but also hold significant implications for guiding future plasma-based surface manufacturing of β-Ga_(2)O_(3).展开更多
20-high mills often face various flatness problems in the production of cold-rolled stainless steel thin strips.The flatness prediction model is essential for flatness control techniques.A novel rapid prediction model...20-high mills often face various flatness problems in the production of cold-rolled stainless steel thin strips.The flatness prediction model is essential for flatness control techniques.A novel rapid prediction model for flatness in a 20-high mill is proposed based on a model coupling method capable of forecasting the flatness of cold-rolled stainless steel thin strips under symmetric and asymmetric rolling conditions.The model integrates deformation coordination equations between rolls,force and moment balance equations,strip exit transverse displacement equations,and no-load roll gap equations into a unified set of linear equations.This solution process avoids repeated iterations between the elastic deformation model of the roll system and the plastic deformation model of the strip,which is a limitation of the traditional method and significantly improves the calculation speed and stability.The accuracy of the model was verified via a ZR22B-52 Sendzimir 20-high mill.The measured and calculated flatness values highly coincided,confirming the model’s accuracy.Rolling calculations of 304 stainless steel thin strips demonstrate that the new model results are consistent with those of the traditional method.The calculation time of the new model is only approximately 0.04%-0.35%that of the traditional method.On this basis,the impact of common flatness control methods on the flatness has been analyzed.展开更多
Atomic-level manufacturing,as the "keystone" of future technology,marks the transformative shift from the micro/nano era based on "classical theory" to the atomic era grounded in "quantum theo...Atomic-level manufacturing,as the "keystone" of future technology,marks the transformative shift from the micro/nano era based on "classical theory" to the atomic era grounded in "quantum theory".It enables the precise control of matter arrangement and composition at the atomic scale,thereby achieving large-scale production of atomically precise and structured products.Electrochemical deposition(ECD),a typical "atom addition" fabrication method for electrochemical atomic and close-to-atomic scale manufacturing(EC-ACSM),enables precise control over material properties at the atomic scale,allowing breakthroughs in revolutionary performance of semiconductors,quantum computing,new materials,nanomedicine,etc.This review explores the fundamentals of EC-ACSM,particularly at the electrode/electrolyte interface,and investigates maskless ECD techniques,highlighting their advantages,limitations,and the role of in situ monitoring and advanced simulations in the process optimization.However,atomic electrochemical deposition faces significant challenges in precise control over atom-ion interactions,electrode-electrolyte interfacial dynamics,and surface defects.In the future,overcoming these obstacles is critical to advancing EC-ACSM and unlocking its full potential in scalability for industrial applications.EC-ACSM can drive the highly customized design of materials and offer strong technological support for the development of future science,ushering in a new atomic era of material innovation and device manufacturing.展开更多
We propose a method to measure the flatness of an object with a petal-like pattern generated by the interference of the measured orbital angular momentum(OAM)beam and the reference OAM beam which carries the opposite ...We propose a method to measure the flatness of an object with a petal-like pattern generated by the interference of the measured orbital angular momentum(OAM)beam and the reference OAM beam which carries the opposite OAM state.By calculating the difference between the petal rotation angle without/with the object,the thickness information of the object,and then the flatness information,can be evaluated.Furthermore,the direction of the object’s flatness can be determined by the petal’s clockwise/counterclockwise rotation.We theoretically analyze the relationship between the object’s thickness and petal rotation angle,and verify the proposed method by experiment.The experimental results show that the proposed method is a high precision flatness measurement and can obtain the convex/concave property of the flatness.For the 1.02 mm glass sample,the mean deviation of the flatness is 1.357×10^(-8) and the variance is 0.242×10^(-16).For the 0.50 mm glass sample,the mean deviation of the flatness is 1.931×10^(-8) and the variance is 2.405×10^(-16).Two different topological charges are adopted for the 2.00 mm glass sample,and their flatness deviations are 0.239×10^(-8)(ℓ=1)and 0.246×10^(-8)(ℓ=2),where their variances are 0.799×10^(-18)(ℓ=1)and 0.775×10^(-18)(ℓ=2),respectively.It is shown that the flatness measured by the proposed method is the same for the same sample when different topological charges are used.All results indicate that the proposed method may provide a high flatness measurement,and will be a promising way to measure the flatness.展开更多
With the increasing demand for higher-quality flatness in downstream industries,the optimization of rolling processes and parameters has become a critical area of research.The effects of rolling force and front tensio...With the increasing demand for higher-quality flatness in downstream industries,the optimization of rolling processes and parameters has become a critical area of research.The effects of rolling force and front tension adjustments on flatness were examined systematically under various rolling process conditions.By embedding the Johnson-Cook constitutive model into the ABAQUS simulation platform through a user-defined subroutine,a series of three-dimensional finite element models for different rolling scenarios were developed.Simulation results indicate that,under all four rolling process conditions,edge strain consistently exceeds center strain,with forward-driven rolling exhibiting greater edge strain than reverse-driven rolling.Along the strip thickness direction,reverse-driven rolling results in higher strain compared to forward-driven rolling.Moreover,in single roll driven rolling,the upper surface of the strip experiences higher strain than the lower surface,while the reverse trend is observed in double roll driven rolling.As the rolling force increases from 1000 to 5000 kN,the strain difference in the width and thickness directions of the strip varies significantly under double roll driven rolling and double roll reverse-driven rolling,with change slopes of 5.74×10^(-6) and-2.85×10^(-6),respectively.Double roll driven rolling effectively prevents the deterioration of flatness along the rolling direction.Furthermore,as the front tension increases from 60 to 100 MPa,double roll reverse-driven rolling significantly suppresses strain differentials in the width,thickness,and rolling directions,with change slopes of-6.73×10^(-4),1.22×10^(-5),and-1.29×10^(-5),respectively.Eventually,a predictive model is established,integrating rolling process,rolling force,and front tension,thereby providing a theoretical framework for advancing the precision and efficiency of strip rolling processes.展开更多
This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the ...This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the lateral component of the centrifugal force acting on the tank on the basis of modeling and analyzing the dynamic model of the low-speed steering system.Secondly,we propose a differential-flatness ADRC approach by converting the under-actuated system to a fully driven flat one.Moreover,we prove the differential flatness of the steering system,which facilitates a two-channel ADRC development.Finally,we show that both the states of the flat system and the original under-actuated system can track the reference trajectory.On the external interference condition,the system is observed to re-track the target signal within 2 s.展开更多
This study explores the dynamic contact response of a viscoelastic functionally graded material(FGM)-coated half-plane under a rigid flat punch subjected to a time-harmonic vertical force.The elastic modulus and mass ...This study explores the dynamic contact response of a viscoelastic functionally graded material(FGM)-coated half-plane under a rigid flat punch subjected to a time-harmonic vertical force.The elastic modulus and mass density of the FGM coating vary exponentially along the thickness direction.The FGM coating and the homogeneous half-plane possess viscoelastic properties,which are described by a linearly hysteretic damping model.By applying the asymptotic method and the Fourier integral transform technique,the contact problem is converted into a Cauchy singular integral equation.The effects of excitation frequency,gradient index,damping factor ratio,and punch width on the vertical impedance and dynamic contact stress are analyzed.The results indicate that adjusting the gradient index of the FGM coating can significantly affect the contact stress and vertical impedance.展开更多
Nanogrinding of SiC wafers with high flatness and low subsurface damage was proposed and nanogrinding experiments were carried out on an ultra precision grinding machine with fine diamond wheels. Experimental results ...Nanogrinding of SiC wafers with high flatness and low subsurface damage was proposed and nanogrinding experiments were carried out on an ultra precision grinding machine with fine diamond wheels. Experimental results show that nanogrinding can produce flatness less than 1.0μm and a surface roughness Ra of 0.42nm. It is found that nanogrinding is capable of producing much flatter SiC wafers with a lower damage than double side lapping and mechanical polishing in much less time and it can replace double side lapping and mechanical polishing and reduce the removal amount of chemical mechanical polishing.展开更多
It is necessary for precise measurement to estimate the uncertainty of measurement result. When measuring flatness error in close way by pitch, usually the uncertainty of measurement result is independently estimated ...It is necessary for precise measurement to estimate the uncertainty of measurement result. When measuring flatness error in close way by pitch, usually the uncertainty of measurement result is independently estimated according to pitch points. By analyzing a concrete example, this paper proposed that the uncertainty should be evaluated by the correlation calculating method. This approach greatly improved the deficiencies of the assessment method according to independent measurement and enhanced measurement precision. It provides a reference value for uncertainty assessment in leveling a flat.展开更多
Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the im...Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced： the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method.展开更多
The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation , which is use...The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation , which is used for general flatness control.As the basis of flatness control system , the efficiencies of flatness actuators provide a quantitative description to the law of flatness control.Therefore , the determination of actuator efficiency factors is crucial in flatness control.The strategies of closed loop feedback flatness control and rolling force feed-forward control were established respectively based on actuator efficiency factors.For the purpose of obtaining accurate efficiency factors matrixes of flatness actuators , a self-learning model of actuator efficiency factors was established.The precision of actuator efficiency factors can be improved continuously by the input of correlative measured flatness data.Meanwhile , the self-learning model of actuator efficiency factors permits the application of this flatness control for all possible types of actuators and every stand type.The application results show that the self-learning model is capable of obtaining good flatness.展开更多
In order to increase the precision of flatness control, considering the principle and the measured data of rolling process essence, the theory-intelligent dynamic matrix model of flatness control is established by usi...In order to increase the precision of flatness control, considering the principle and the measured data of rolling process essence, the theory-intelligent dynamic matrix model of flatness control is established by using theory and in-telligent methods synthetically. The network model for rapidly calculating the theory effective matrix is established by the BP network optimized by the particle swarm algorithm. The network model for rapidly calculating the meas- urement effective matrix is established by the RBF network optimized by the cluster algorithm. The flatness control model can track the practical situation of roiling process by on-line selVlearning. The scheme for flatness control quantity calculation is established by combining the theory control matrix and the measurement control matrix. The simulation result indicates that the establishment of theory-intelligent dynamic matrix model of flatness control with stable control process and high precision supplies a new way and method for studying flatness on-line control model.展开更多
For the problems occurring in a least square method model, a fuzzy model, and a neural network model for flatness pattern recognition, a fuzzy neural network model for flatness pattern recognition with only three-inpu...For the problems occurring in a least square method model, a fuzzy model, and a neural network model for flatness pattern recognition, a fuzzy neural network model for flatness pattern recognition with only three-input and three output signals was proposed with Legendre orthodoxy polynomial as basic pattern, based on fuzzy logic expert experiential knowledge and genetic-BP hybrid optimization algorithm. The model not only had definite physical meanings in its inner nodes, but also had strong self-adaptability, anti interference ability, high recognition precision, and high velocity, thereby meeting the demand of high-precision flatness control for cold strip mill and providing a convenient, practical, and novel method for flatness pattern recognition.展开更多
In connection with the characteristics of multi-disturbance and nonlinearity of a system for flatness control in cold rolling process, a new intelligent PID control algorithm was proposed based on a cloud model, neura...In connection with the characteristics of multi-disturbance and nonlinearity of a system for flatness control in cold rolling process, a new intelligent PID control algorithm was proposed based on a cloud model, neural network and fuzzy integration. By indeterminacy artificial intelligence, the problem of fixing the membership functions of input variables and fuzzy rules was solved in an actual fuzzy system and the nonlinear mapping between variables was implemented by neural network. The algorithm has the adaptive learning ability of neural network and the indetermi- nacy of a cloud model in processing knowledge, which makes the fuzzy system have more persuasion in the process of knowledge inference, realizing the online adaptive regulation of PID parameters and avoiding the defects of the traditional PID controller. Simulation results show that the algorithm is simple, fast and robust with good control performance and application value.展开更多
In this article, we establish the route taken by the author, and his research group, to bring differential flatness to the realm of active disturbance rejection control （ADRC）. This avenue entitled： 1） generalized...In this article, we establish the route taken by the author, and his research group, to bring differential flatness to the realm of active disturbance rejection control （ADRC）. This avenue entitled： 1） generalized proportional integral observers （GPIO）, as natural state and disturbance observers for fiat systems, 2） generalized proportional integral （GPI） control, provided with extra integrations, to produce a modular controller known as flat filters （FF＇s） and, finally, 3） the establishing of an equivalence of observer based ADRC with FF＇s. The context is that of pure integration systems. The obtained controllers depend only on the order of the flat system and they are to be directly used on the basis of the available flat output signal in a universal, modular, fashion. The map is complemented with the relevant references where the intermediate techniques were illustrated and developed, over the years, in connection with laboratory experimental implementations.展开更多
In flatness measuring system, the flatness measuring signal can be affected by the deflection of flatness measuring roll. The stress on flatness measuring roll was analyzed and a deflection model for the flatness meas...In flatness measuring system, the flatness measuring signal can be affected by the deflection of flatness measuring roll. The stress on flatness measuring roll was analyzed and a deflection model for the flatness measuring roll was obtained by using the influence function method. The model was developed on the basis of the deformation of flatness measuring roll in roiling process and compensation curve was obtained. The results indicated that the set curve of flatness is in good agreement with the online measured curve of flatness, and good strip flatness can be obtained.展开更多
In cold rolling process,the flatness actuator efficiency is the basis of the flatness control system.The precision of flatness is determined by the setpoints of flatness actuators.In the presence of modeling uncertain...In cold rolling process,the flatness actuator efficiency is the basis of the flatness control system.The precision of flatness is determined by the setpoints of flatness actuators.In the presence of modeling uncertainties and unmodeled nonlinearities in rolling process,it is difficult to obtain efficiency factors and setpoints of flatness actuators accurately.Based on the production data,a method to obtain the flatness actuator efficiency by using partial least square(PLS)combined with orthogonal signal correction(OSC)was adopted.Compared with the experiential method and principal component analysis method,the OSC-PLS method shows superior performance in obtaining the flatness actuator efficiency factors at the last stand.Furthermore,kernel partial least square combined with artificial neural network(KPLS-ANN)was proposed to predict the flatness values and optimize the setpoints of flatness actuators.Compared with KPLS or ANN,KPLS-ANN shows the best predictive ability.The root mean square error,mean absolute error and mean absolute percentage error are 0.51 IU,0.34 IU and 0.09,respectively.After the setpoints of flatness actuators are optimized,KPLS-ANN shows better optimization ability.The result in an average flatness standard deviation is 2.22 IU,while the unoptimized value is 4.10 IU.展开更多
The strip flatness and crown control model is the foundation of automatic strip shape control. Considering the metal transverse flows and the inter stand second deformation, the trip flatness and crown control model h...The strip flatness and crown control model is the foundation of automatic strip shape control. Considering the metal transverse flows and the inter stand second deformation, the trip flatness and crown control model has been developed, which can be applied to CVC mills and PC mills as well as normal four-high mills. The strip flatness and crown control model has high precision, and has been successfully applied to the automatic strip shape control system reconstruction of Tangshan Ganglu 1 250 mm hot strip plant.展开更多
A simple plate crown model was introduced,and the crown-flatness vector analysis method was analyzed.Based on the plate rolling technology,the rolling schedule design of elongation phase is divided into three steps.Fi...A simple plate crown model was introduced,and the crown-flatness vector analysis method was analyzed.Based on the plate rolling technology,the rolling schedule design of elongation phase is divided into three steps.First step is to calculate the reductions of first pass of elongation making full use of the mill capability to decrease the total pass number.The second step is to calculate the pass reduction for the last three or four passes to control crown and flatness by crown-flatness vector analysis method.In the third step,the maximum rolling force limit and the total pass number are adjusted to make the plate gauge at exit equal to target gauge with satisfactory flatness.The on-line application shows that this method is effective.展开更多
基金supported by the National Natural Science Foundation of China(52375437,52035009)the Natural Science Foundation of Guangdong Province(2024B1515020027)+2 种基金the Shenzhen Science and Technology Program(Grant No.KQTD20170810110250357)for the financial supportthe assistance of SUSTech Core Research Facilitiessupported by Shenzhen Engineering Research Center for Semiconductorspecific Equipment。
文摘The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method named plasma-based atom-selective etching(PASE)is proposed to achieve the highly efficient,atomic-scale,and damage-free polishing of β-Ga_(2)O_(3).The plasma is excited through the inductive coupling principle and carbon tetrafluoride is utilized as the main reaction gas to etch β-Ga_(2)O_(3).The core of PASE polishing of β-Ga_(2)O_(3)is the remarkable lateral etching effect,which is ensured by both the intrinsic property of the surface and the extrinsic temperature condition.As revealed by density functional theory-based calculations,the intrinsic difference in the etching energy barrier of atoms at the step edge(2.36 eV)and in the terrace plane(4.37 eV)determines their difference in the etching rate,and their etching rate difference can be greatly enlarged by increasing the extrinsic temperature.The polishing of β-Ga_(2)O_(3)based on the lateral etching effect is further verified in the etching experiments.The Sa roughness of β-Ga_(2)O_(3)(001)substrate is reduced from 14.8 nm to 0.057 nm within 120 s,and the corresponding material removal rate reaches up to 20.96μm·min^(−1).The polished β-Ga_(2)O_(3)displays significantly improved crystalline quality and photoluminescence intensity,and the polishing effect of PASE is independent of the crystal face of β-Ga_(2)O_(3).In addition,the competition between chemical etching and physical reconstruction,which is determined by temperature and greatly affects the surface state of β-Ga_(2)O_(3),is deeply studied for the first time.These findings not only demonstrate the high-efficiency and high-quality polishing of β-Ga_(2)O_(3)via atmospheric plasma etching but also hold significant implications for guiding future plasma-based surface manufacturing of β-Ga_(2)O_(3).
基金supported by the National Natural Science Foundation of China(No.U21A20118)the Natural Science Foundation of Hebei Province(No.E2023203065)the National Key Laboratory of Metal Forming Technology and Heavy Equipment,China National Heavy Machinery Research Institute Co.,Ltd.(No.S2208100.W04).Author infor。
文摘20-high mills often face various flatness problems in the production of cold-rolled stainless steel thin strips.The flatness prediction model is essential for flatness control techniques.A novel rapid prediction model for flatness in a 20-high mill is proposed based on a model coupling method capable of forecasting the flatness of cold-rolled stainless steel thin strips under symmetric and asymmetric rolling conditions.The model integrates deformation coordination equations between rolls,force and moment balance equations,strip exit transverse displacement equations,and no-load roll gap equations into a unified set of linear equations.This solution process avoids repeated iterations between the elastic deformation model of the roll system and the plastic deformation model of the strip,which is a limitation of the traditional method and significantly improves the calculation speed and stability.The accuracy of the model was verified via a ZR22B-52 Sendzimir 20-high mill.The measured and calculated flatness values highly coincided,confirming the model’s accuracy.Rolling calculations of 304 stainless steel thin strips demonstrate that the new model results are consistent with those of the traditional method.The calculation time of the new model is only approximately 0.04%-0.35%that of the traditional method.On this basis,the impact of common flatness control methods on the flatness has been analyzed.
基金the support from the National Natural Science Foundation of China (Grant Nos. 52405447 and 52275299)the National Key Research and Development Program of China (Grant No. 2021YFB1716200)the Key Research and Development Program of Jiangxi Province in China (Grant No. 20232BBE50011)。
文摘Atomic-level manufacturing,as the "keystone" of future technology,marks the transformative shift from the micro/nano era based on "classical theory" to the atomic era grounded in "quantum theory".It enables the precise control of matter arrangement and composition at the atomic scale,thereby achieving large-scale production of atomically precise and structured products.Electrochemical deposition(ECD),a typical "atom addition" fabrication method for electrochemical atomic and close-to-atomic scale manufacturing(EC-ACSM),enables precise control over material properties at the atomic scale,allowing breakthroughs in revolutionary performance of semiconductors,quantum computing,new materials,nanomedicine,etc.This review explores the fundamentals of EC-ACSM,particularly at the electrode/electrolyte interface,and investigates maskless ECD techniques,highlighting their advantages,limitations,and the role of in situ monitoring and advanced simulations in the process optimization.However,atomic electrochemical deposition faces significant challenges in precise control over atom-ion interactions,electrode-electrolyte interfacial dynamics,and surface defects.In the future,overcoming these obstacles is critical to advancing EC-ACSM and unlocking its full potential in scalability for industrial applications.EC-ACSM can drive the highly customized design of materials and offer strong technological support for the development of future science,ushering in a new atomic era of material innovation and device manufacturing.
基金supported by the National Natural Science Foundation of China(Grant No.62375140)the Open Research Fund of National Laboratory of Solid State Microstructures(Grant No.M36055).
文摘We propose a method to measure the flatness of an object with a petal-like pattern generated by the interference of the measured orbital angular momentum(OAM)beam and the reference OAM beam which carries the opposite OAM state.By calculating the difference between the petal rotation angle without/with the object,the thickness information of the object,and then the flatness information,can be evaluated.Furthermore,the direction of the object’s flatness can be determined by the petal’s clockwise/counterclockwise rotation.We theoretically analyze the relationship between the object’s thickness and petal rotation angle,and verify the proposed method by experiment.The experimental results show that the proposed method is a high precision flatness measurement and can obtain the convex/concave property of the flatness.For the 1.02 mm glass sample,the mean deviation of the flatness is 1.357×10^(-8) and the variance is 0.242×10^(-16).For the 0.50 mm glass sample,the mean deviation of the flatness is 1.931×10^(-8) and the variance is 2.405×10^(-16).Two different topological charges are adopted for the 2.00 mm glass sample,and their flatness deviations are 0.239×10^(-8)(ℓ=1)and 0.246×10^(-8)(ℓ=2),where their variances are 0.799×10^(-18)(ℓ=1)and 0.775×10^(-18)(ℓ=2),respectively.It is shown that the flatness measured by the proposed method is the same for the same sample when different topological charges are used.All results indicate that the proposed method may provide a high flatness measurement,and will be a promising way to measure the flatness.
基金supported by National Key R&D Program of China(No.2024YFB4007100).
文摘With the increasing demand for higher-quality flatness in downstream industries,the optimization of rolling processes and parameters has become a critical area of research.The effects of rolling force and front tension adjustments on flatness were examined systematically under various rolling process conditions.By embedding the Johnson-Cook constitutive model into the ABAQUS simulation platform through a user-defined subroutine,a series of three-dimensional finite element models for different rolling scenarios were developed.Simulation results indicate that,under all four rolling process conditions,edge strain consistently exceeds center strain,with forward-driven rolling exhibiting greater edge strain than reverse-driven rolling.Along the strip thickness direction,reverse-driven rolling results in higher strain compared to forward-driven rolling.Moreover,in single roll driven rolling,the upper surface of the strip experiences higher strain than the lower surface,while the reverse trend is observed in double roll driven rolling.As the rolling force increases from 1000 to 5000 kN,the strain difference in the width and thickness directions of the strip varies significantly under double roll driven rolling and double roll reverse-driven rolling,with change slopes of 5.74×10^(-6) and-2.85×10^(-6),respectively.Double roll driven rolling effectively prevents the deterioration of flatness along the rolling direction.Furthermore,as the front tension increases from 60 to 100 MPa,double roll reverse-driven rolling significantly suppresses strain differentials in the width,thickness,and rolling directions,with change slopes of-6.73×10^(-4),1.22×10^(-5),and-1.29×10^(-5),respectively.Eventually,a predictive model is established,integrating rolling process,rolling force,and front tension,thereby providing a theoretical framework for advancing the precision and efficiency of strip rolling processes.
基金supported by the National Natural Science Foundation of China(62422305,62373049).
文摘This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the lateral component of the centrifugal force acting on the tank on the basis of modeling and analyzing the dynamic model of the low-speed steering system.Secondly,we propose a differential-flatness ADRC approach by converting the under-actuated system to a fully driven flat one.Moreover,we prove the differential flatness of the steering system,which facilitates a two-channel ADRC development.Finally,we show that both the states of the flat system and the original under-actuated system can track the reference trajectory.On the external interference condition,the system is observed to re-track the target signal within 2 s.
基金Project supported by the National Natural Science Foundation of China(Nos.12021002,12192212,and 12462007)。
文摘This study explores the dynamic contact response of a viscoelastic functionally graded material(FGM)-coated half-plane under a rigid flat punch subjected to a time-harmonic vertical force.The elastic modulus and mass density of the FGM coating vary exponentially along the thickness direction.The FGM coating and the homogeneous half-plane possess viscoelastic properties,which are described by a linearly hysteretic damping model.By applying the asymptotic method and the Fourier integral transform technique,the contact problem is converted into a Cauchy singular integral equation.The effects of excitation frequency,gradient index,damping factor ratio,and punch width on the vertical impedance and dynamic contact stress are analyzed.The results indicate that adjusting the gradient index of the FGM coating can significantly affect the contact stress and vertical impedance.
基金Project (50975040) supported by the National Natural Science Foundation of China
文摘Nanogrinding of SiC wafers with high flatness and low subsurface damage was proposed and nanogrinding experiments were carried out on an ultra precision grinding machine with fine diamond wheels. Experimental results show that nanogrinding can produce flatness less than 1.0μm and a surface roughness Ra of 0.42nm. It is found that nanogrinding is capable of producing much flatter SiC wafers with a lower damage than double side lapping and mechanical polishing in much less time and it can replace double side lapping and mechanical polishing and reduce the removal amount of chemical mechanical polishing.
文摘It is necessary for precise measurement to estimate the uncertainty of measurement result. When measuring flatness error in close way by pitch, usually the uncertainty of measurement result is independently estimated according to pitch points. By analyzing a concrete example, this paper proposed that the uncertainty should be evaluated by the correlation calculating method. This approach greatly improved the deficiencies of the assessment method according to independent measurement and enhanced measurement precision. It provides a reference value for uncertainty assessment in leveling a flat.
基金supported by National Natural Science Foundation of China(Grant No. 50675186)Hebei Provincial Major Natural Science Foundation of China (Grant No. E2006001038)
文摘Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced： the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method.
基金Item Sponsored by National Science and Technology Support Plan of China ( 2011BAF15B01 , 2011BAF15B03 )Provincial Natural Science Foundation of Hebei of China ( E2011203004 )
文摘The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation , which is used for general flatness control.As the basis of flatness control system , the efficiencies of flatness actuators provide a quantitative description to the law of flatness control.Therefore , the determination of actuator efficiency factors is crucial in flatness control.The strategies of closed loop feedback flatness control and rolling force feed-forward control were established respectively based on actuator efficiency factors.For the purpose of obtaining accurate efficiency factors matrixes of flatness actuators , a self-learning model of actuator efficiency factors was established.The precision of actuator efficiency factors can be improved continuously by the input of correlative measured flatness data.Meanwhile , the self-learning model of actuator efficiency factors permits the application of this flatness control for all possible types of actuators and every stand type.The application results show that the self-learning model is capable of obtaining good flatness.
基金Item Sponsored by National High-Tech Research and Development Project of China(2009AA04Z143)Natural Science Foundation of Hebei Province of China(E2006001038)Hebei Provincial Science and Technology Project of China(10212101D)
文摘In order to increase the precision of flatness control, considering the principle and the measured data of rolling process essence, the theory-intelligent dynamic matrix model of flatness control is established by using theory and in-telligent methods synthetically. The network model for rapidly calculating the theory effective matrix is established by the BP network optimized by the particle swarm algorithm. The network model for rapidly calculating the meas- urement effective matrix is established by the RBF network optimized by the cluster algorithm. The flatness control model can track the practical situation of roiling process by on-line selVlearning. The scheme for flatness control quantity calculation is established by combining the theory control matrix and the measurement control matrix. The simulation result indicates that the establishment of theory-intelligent dynamic matrix model of flatness control with stable control process and high precision supplies a new way and method for studying flatness on-line control model.
基金Item Sponsored by National Natural Science Foundation of China and Shanghai Baosteel Group Co(50675186)Provincial Natural Science Foundation of Hebei Province of China(E2006001038)
文摘For the problems occurring in a least square method model, a fuzzy model, and a neural network model for flatness pattern recognition, a fuzzy neural network model for flatness pattern recognition with only three-input and three output signals was proposed with Legendre orthodoxy polynomial as basic pattern, based on fuzzy logic expert experiential knowledge and genetic-BP hybrid optimization algorithm. The model not only had definite physical meanings in its inner nodes, but also had strong self-adaptability, anti interference ability, high recognition precision, and high velocity, thereby meeting the demand of high-precision flatness control for cold strip mill and providing a convenient, practical, and novel method for flatness pattern recognition.
基金Sponsored by National High-tech Research and Development Project of China(2009AA04Z143)Natural Science Foundation of Hebei Province of China(E2006001038)Science and Technology Project of Hebei Province of China(10212101D)
文摘In connection with the characteristics of multi-disturbance and nonlinearity of a system for flatness control in cold rolling process, a new intelligent PID control algorithm was proposed based on a cloud model, neural network and fuzzy integration. By indeterminacy artificial intelligence, the problem of fixing the membership functions of input variables and fuzzy rules was solved in an actual fuzzy system and the nonlinear mapping between variables was implemented by neural network. The algorithm has the adaptive learning ability of neural network and the indetermi- nacy of a cloud model in processing knowledge, which makes the fuzzy system have more persuasion in the process of knowledge inference, realizing the online adaptive regulation of PID parameters and avoiding the defects of the traditional PID controller. Simulation results show that the algorithm is simple, fast and robust with good control performance and application value.
文摘In this article, we establish the route taken by the author, and his research group, to bring differential flatness to the realm of active disturbance rejection control （ADRC）. This avenue entitled： 1） generalized proportional integral observers （GPIO）, as natural state and disturbance observers for fiat systems, 2） generalized proportional integral （GPI） control, provided with extra integrations, to produce a modular controller known as flat filters （FF＇s） and, finally, 3） the establishing of an equivalence of observer based ADRC with FF＇s. The context is that of pure integration systems. The obtained controllers depend only on the order of the flat system and they are to be directly used on the basis of the available flat output signal in a universal, modular, fashion. The map is complemented with the relevant references where the intermediate techniques were illustrated and developed, over the years, in connection with laboratory experimental implementations.
基金Item Sponsored by National Natural Science Foundation of China(50534020)
文摘In flatness measuring system, the flatness measuring signal can be affected by the deflection of flatness measuring roll. The stress on flatness measuring roll was analyzed and a deflection model for the flatness measuring roll was obtained by using the influence function method. The model was developed on the basis of the deformation of flatness measuring roll in roiling process and compensation curve was obtained. The results indicated that the set curve of flatness is in good agreement with the online measured curve of flatness, and good strip flatness can be obtained.
基金This study is financially supported by the National Key Research and Development Program of China(No.2017YFB0304100)the National Natural Science Foundation of China(Nos.51774084,51704067,and 51634002)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.N160704004,N170708020,and N2004010)Liaoning Revitalization Talents Program(XLYC1907065).
文摘In cold rolling process,the flatness actuator efficiency is the basis of the flatness control system.The precision of flatness is determined by the setpoints of flatness actuators.In the presence of modeling uncertainties and unmodeled nonlinearities in rolling process,it is difficult to obtain efficiency factors and setpoints of flatness actuators accurately.Based on the production data,a method to obtain the flatness actuator efficiency by using partial least square(PLS)combined with orthogonal signal correction(OSC)was adopted.Compared with the experiential method and principal component analysis method,the OSC-PLS method shows superior performance in obtaining the flatness actuator efficiency factors at the last stand.Furthermore,kernel partial least square combined with artificial neural network(KPLS-ANN)was proposed to predict the flatness values and optimize the setpoints of flatness actuators.Compared with KPLS or ANN,KPLS-ANN shows the best predictive ability.The root mean square error,mean absolute error and mean absolute percentage error are 0.51 IU,0.34 IU and 0.09,respectively.After the setpoints of flatness actuators are optimized,KPLS-ANN shows better optimization ability.The result in an average flatness standard deviation is 2.22 IU,while the unoptimized value is 4.10 IU.
基金Item Sponsored by National Natural Science Foundation of China (50534020)
文摘The strip flatness and crown control model is the foundation of automatic strip shape control. Considering the metal transverse flows and the inter stand second deformation, the trip flatness and crown control model has been developed, which can be applied to CVC mills and PC mills as well as normal four-high mills. The strip flatness and crown control model has high precision, and has been successfully applied to the automatic strip shape control system reconstruction of Tangshan Ganglu 1 250 mm hot strip plant.
基金Item Sponsored by National Natural Science Foundation of China(50104004)
文摘A simple plate crown model was introduced,and the crown-flatness vector analysis method was analyzed.Based on the plate rolling technology,the rolling schedule design of elongation phase is divided into three steps.First step is to calculate the reductions of first pass of elongation making full use of the mill capability to decrease the total pass number.The second step is to calculate the pass reduction for the last three or four passes to control crown and flatness by crown-flatness vector analysis method.In the third step,the maximum rolling force limit and the total pass number are adjusted to make the plate gauge at exit equal to target gauge with satisfactory flatness.The on-line application shows that this method is effective.
