Purpose For the High Energy Photon Source(HEPS),a green-field fourth-generation storage ring light source,the prelimi-nary design report(PDR)was completed in 2018,when the accelerator physics design had been basically...Purpose For the High Energy Photon Source(HEPS),a green-field fourth-generation storage ring light source,the prelimi-nary design report(PDR)was completed in 2018,when the accelerator physics design had been basically finished.During the subsequent hardware and engineering design of the HEPS storage ring based on the PDR design,a few problems and challenges emerged,calling for modifications of the lattice.Method In this paper,we will introduce the background and reasons for the modifications and present the linear optics and simulation results for the nonlinear performance of the modified lattice of the HEPS storage ring.Result and conclusion The modified lattice satisfies the requirements from hardware and engineering design.展开更多
This paper is devoted to the finite-time disturbance attenuation problem of affine nonlinear systems. Based on the finite time Lyapunov stability theory, some finite-time H∞ performance criterions are derived. Then t...This paper is devoted to the finite-time disturbance attenuation problem of affine nonlinear systems. Based on the finite time Lyapunov stability theory, some finite-time H∞ performance criterions are derived. Then the state-feedback control law is designed and the structure of such a controller is investigated. Furthermore, it is shown that the H∞ controller can also make the closed-loop system satisfy finite-time H∞ performance for nonlinear homogeneous systems. An example is provided to demonstrate the effectiveness of the presented results.展开更多
Professor T. T. Soong is one of the early pioneers in field of earthquake responsc control of structures. A new type of smart damper, which is based on an Energy Dissipating Restraint （EDR）, is presented in this pap...Professor T. T. Soong is one of the early pioneers in field of earthquake responsc control of structures. A new type of smart damper, which is based on an Energy Dissipating Restraint （EDR）, is presented in this paper. The EDR by Nims and Kelly, which has a triangle hysteretic loop, behaves like an active variable stiffness system （AVS） and possesses the basic characteristics of a linear viscous damper but has difficulty in capturing the output and large stroke simultaneously needed for practical applicataions in engineering structures. In order to overcome this limitation, the friction surface in the original Sumitomo EDR is divided into two parts with low and high friction coefficients in this paper. The results of finite element analysis studies show that the new type of smart friction damper enables large friction force in proportion to relative displacement between two ends of the damper and has a large allowable displacement to fit the demands of engineering applications. However, unlike the EDR by Nims and Kelly, this type of friction variable damper cannot self re-center. However, the lateral stiffness can be used to restore the structure. The nonlinear time history analysis of earthquake response for a structure equipped with the proposed friction variable dampers was carried out using the IDARC computer program. The results indicate that the proposed damper can successfully reduce the earthquake response of a structure.展开更多
Optimal design theory for linear tuned mass dampers （TMD） has been thoroughly investigated, but is still under development for nonlinear TMDs. In this paper, optimization procedures in the time domain are proposed f...Optimal design theory for linear tuned mass dampers （TMD） has been thoroughly investigated, but is still under development for nonlinear TMDs. In this paper, optimization procedures in the time domain are proposed for design of a TMD with nonlinear viscous damping. A dynamic analysis of a structure implemented with a nonlinear TMD is conducted first. Optimum design parameters for the nonlinear TMD are searched using an optimization method to minimize the performance index. The feasibility of the proposed optimization method is illustrated numerically by using the Taipei 101 structure implemented with TMD. The sensitivity analysis shows that the performance index is less sensitive to the damping coefficient than to the frequency ratio. Time history analysis is conducted using the Taipei 101 structure implemented with different TMDs under wind excitation. For both linear and nonlinear TMDs, the comfort requirements for building occupants are satisfied as long as the TMD is properly designed. It was found that as the damping exponent increases, the relative displacement of the TMD decreases but the damping force increases.展开更多
Evaluation of grade and recovery plays an important role in process control and plant profitability in mineral processing operations, especially flotation. The accurate measurement or estimation of these two parameter...Evaluation of grade and recovery plays an important role in process control and plant profitability in mineral processing operations, especially flotation. The accurate measurement or estimation of these two parameters, based on the secondary variables, is a critical issue. Data-driven modeling techniques, which entail comprehensive data analysis and implementation of machine learning methods for system forecast, provide an attractive alternative. In this paper, two types of artificial neural networks(ANNs),namely radial basis function neural network(RBFNN) and layer recurrent neural network(RNN), and also a multivariate nonlinear regression(MNLR) model were employed to predict metallurgical performance of the flotation column. The training capacity and the accuracy of these three above mentioned types of models were compared. In order to acquire data for the simulation, a case study was conducted at Sarcheshmeh copper complex pilot plant. Based on the root mean squared error and correlation coefficient values, at training and testing stages, the RNN forecasted the metallurgical performance of the flotation column better than RBF and MNLR models. The RNN could predict Cu grade and recovery with correlation coefficients of 0.92 and 0.9, respectively in testing process.展开更多
Microbial fuel cell(MFC)is a kind of promising clean power supply energy equipment,but serious nonlinearities and disturbances exist when the MFC runs,and it is an important topic to guarantee that the output voltage ...Microbial fuel cell(MFC)is a kind of promising clean power supply energy equipment,but serious nonlinearities and disturbances exist when the MFC runs,and it is an important topic to guarantee that the output voltage reaches the setting value quickly and smoothly.Regulating the feeding flow is an effective way to achieve this goal,and especially,the satisfactory results can be achieved by regulating anode feeding flow.In this work,a feedforward fuzzy logic PID algorithm is proposed.The fuzzy logic system is introduced to deal with the non-linear dynamics of MFC,and corresponding PID parameters are calculated according to defuzzification.The magnitude value of the current density is used to simulate the value of the external load.The simulation results indicate that the MFC output voltage can track the setting value quickly and smoothly with the proposed feedforward fuzzy logic PID algorithm.The proposed algorithm is more efficient and robust with respect to anti-disturbance performance and tracking accuracy than other three control methods.展开更多
A new nonlinear variable structure excitation controller is proposed. Its design combines the differential geometry theory and the variable structure controlling theory. The mathematical model in the form of ＂an affm...A new nonlinear variable structure excitation controller is proposed. Its design combines the differential geometry theory and the variable structure controlling theory. The mathematical model in the form of ＂an affme nonlinear system＂ is set up for the control of a large-scale power system. The static and dynamic performances of the nonlinear variable structure controller are simulated. The response of system with the controller proposed is compared to that of the nonlinear optimal controller when the system is subjected to a variety of disturbances. Simulation results show that the nonlinear variable structure excitation controller gives more satisfactorily static and dynamic performance and better robustness.展开更多
基金supported by the High Energy Photon Source(HEPS),a major national science and technol-ogy infrastructurethe National Natural Science Foundation of China(No.11922512)+1 种基金Youth Inno-vation Promotion Association of Chinese Academy of Sciences(No.Y201904)Bureau of Frontier Sciences and Education of Chinese Academy of Sciences(No.QYZDJ-SSW-SLH001)
文摘Purpose For the High Energy Photon Source(HEPS),a green-field fourth-generation storage ring light source,the prelimi-nary design report(PDR)was completed in 2018,when the accelerator physics design had been basically finished.During the subsequent hardware and engineering design of the HEPS storage ring based on the PDR design,a few problems and challenges emerged,calling for modifications of the lattice.Method In this paper,we will introduce the background and reasons for the modifications and present the linear optics and simulation results for the nonlinear performance of the modified lattice of the HEPS storage ring.Result and conclusion The modified lattice satisfies the requirements from hardware and engineering design.
基金Supported by the National Basic Research Program of China (Grant No. 2005CB321902)the National Natural Science Foundation of China(Grant No. 60374001)the Doctoral Fund of Ministry of Education of China (Grant No. 20030006003)
文摘This paper is devoted to the finite-time disturbance attenuation problem of affine nonlinear systems. Based on the finite time Lyapunov stability theory, some finite-time H∞ performance criterions are derived. Then the state-feedback control law is designed and the structure of such a controller is investigated. Furthermore, it is shown that the H∞ controller can also make the closed-loop system satisfy finite-time H∞ performance for nonlinear homogeneous systems. An example is provided to demonstrate the effectiveness of the presented results.
基金National Basic Research Program of China (973 Program) Under Grant No. 2007CB714200
文摘Professor T. T. Soong is one of the early pioneers in field of earthquake responsc control of structures. A new type of smart damper, which is based on an Energy Dissipating Restraint （EDR）, is presented in this paper. The EDR by Nims and Kelly, which has a triangle hysteretic loop, behaves like an active variable stiffness system （AVS） and possesses the basic characteristics of a linear viscous damper but has difficulty in capturing the output and large stroke simultaneously needed for practical applicataions in engineering structures. In order to overcome this limitation, the friction surface in the original Sumitomo EDR is divided into two parts with low and high friction coefficients in this paper. The results of finite element analysis studies show that the new type of smart friction damper enables large friction force in proportion to relative displacement between two ends of the damper and has a large allowable displacement to fit the demands of engineering applications. However, unlike the EDR by Nims and Kelly, this type of friction variable damper cannot self re-center. However, the lateral stiffness can be used to restore the structure. The nonlinear time history analysis of earthquake response for a structure equipped with the proposed friction variable dampers was carried out using the IDARC computer program. The results indicate that the proposed damper can successfully reduce the earthquake response of a structure.
文摘Optimal design theory for linear tuned mass dampers （TMD） has been thoroughly investigated, but is still under development for nonlinear TMDs. In this paper, optimization procedures in the time domain are proposed for design of a TMD with nonlinear viscous damping. A dynamic analysis of a structure implemented with a nonlinear TMD is conducted first. Optimum design parameters for the nonlinear TMD are searched using an optimization method to minimize the performance index. The feasibility of the proposed optimization method is illustrated numerically by using the Taipei 101 structure implemented with TMD. The sensitivity analysis shows that the performance index is less sensitive to the damping coefficient than to the frequency ratio. Time history analysis is conducted using the Taipei 101 structure implemented with different TMDs under wind excitation. For both linear and nonlinear TMDs, the comfort requirements for building occupants are satisfied as long as the TMD is properly designed. It was found that as the damping exponent increases, the relative displacement of the TMD decreases but the damping force increases.
基金the support of the Department of Research and Development of Sarcheshmeh Copper Plants for this research
文摘Evaluation of grade and recovery plays an important role in process control and plant profitability in mineral processing operations, especially flotation. The accurate measurement or estimation of these two parameters, based on the secondary variables, is a critical issue. Data-driven modeling techniques, which entail comprehensive data analysis and implementation of machine learning methods for system forecast, provide an attractive alternative. In this paper, two types of artificial neural networks(ANNs),namely radial basis function neural network(RBFNN) and layer recurrent neural network(RNN), and also a multivariate nonlinear regression(MNLR) model were employed to predict metallurgical performance of the flotation column. The training capacity and the accuracy of these three above mentioned types of models were compared. In order to acquire data for the simulation, a case study was conducted at Sarcheshmeh copper complex pilot plant. Based on the root mean squared error and correlation coefficient values, at training and testing stages, the RNN forecasted the metallurgical performance of the flotation column better than RBF and MNLR models. The RNN could predict Cu grade and recovery with correlation coefficients of 0.92 and 0.9, respectively in testing process.
基金Project(61563032)supported by the National Natural Science Foundation of ChinaProject(18JR3RA133)supported by Gansu Basic Research Innovation Group,China
文摘Microbial fuel cell(MFC)is a kind of promising clean power supply energy equipment,but serious nonlinearities and disturbances exist when the MFC runs,and it is an important topic to guarantee that the output voltage reaches the setting value quickly and smoothly.Regulating the feeding flow is an effective way to achieve this goal,and especially,the satisfactory results can be achieved by regulating anode feeding flow.In this work,a feedforward fuzzy logic PID algorithm is proposed.The fuzzy logic system is introduced to deal with the non-linear dynamics of MFC,and corresponding PID parameters are calculated according to defuzzification.The magnitude value of the current density is used to simulate the value of the external load.The simulation results indicate that the MFC output voltage can track the setting value quickly and smoothly with the proposed feedforward fuzzy logic PID algorithm.The proposed algorithm is more efficient and robust with respect to anti-disturbance performance and tracking accuracy than other three control methods.
文摘A new nonlinear variable structure excitation controller is proposed. Its design combines the differential geometry theory and the variable structure controlling theory. The mathematical model in the form of ＂an affme nonlinear system＂ is set up for the control of a large-scale power system. The static and dynamic performances of the nonlinear variable structure controller are simulated. The response of system with the controller proposed is compared to that of the nonlinear optimal controller when the system is subjected to a variety of disturbances. Simulation results show that the nonlinear variable structure excitation controller gives more satisfactorily static and dynamic performance and better robustness.
