In the large-scale distributed hardware-in-the-loop radar simulation system based on HLA, a new solution of processing after acquisition is proposed, which separates the software subsystem from the hardware jammer sub...In the large-scale distributed hardware-in-the-loop radar simulation system based on HLA, a new solution of processing after acquisition is proposed, which separates the software subsystem from the hardware jammer subsystem by a response database, so as to settle the problem, that the software subsystem can not meet the real-time need of the hardware, with very little increment of code. And the data completeness and feasibility of this solution are discussed.展开更多
To enhance the fidelity and accuracy of the simulation of communication networks,hardware-in-the-loop（HITL） simulation was employed.HITL simulation methods was classified into three categories,of which the merits an...To enhance the fidelity and accuracy of the simulation of communication networks,hardware-in-the-loop（HITL） simulation was employed.HITL simulation methods was classified into three categories,of which the merits and shortages were compared.Combing system-in-the-loop（SITL） simulation principle with high level architecture（HLA）,an HITL simulation model of asynchronous transfer mode（ATM） network was constructed.The throughput and end-to-end delay of all-digital simulation and HITL simulation was analyzed,which showed that HITL simulation was more reliable and effectively improved the simulation credibility of communication network.Meanwhile,HLA-SITL method was fast and easy to achieve and low-cost during design lifecycle.Thus,it was a feasible way to research and analyze the large-scale network.展开更多
A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit（ECU）in modem diesel engine...A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit（ECU）in modem diesel engines, and to diminish potential damages on components or human exposure to dangers in R＆D en- deavor. This plat-form consists of a computer installed with software Matlab/Simulink/RTW and dSPACE/ ControlDesk; a diesel engine ECU, and a dSPACE autobox which runs a real-time diesel engine model. A typical model of diesel engine with turbocharger and intercooler is presented. Based on this model our research is carried out with a real ECU to test its software control strategies. Results show that by using the diesel engine model downloaded inside, the hardware-in-the-loop platform can simulate diesel engine＇s working conditions and generate all kinds of sensor signals which ECU needs on a real-time basis. So the ECU control strategies can be validated and relevant parameters roughly calibrated.展开更多
The simulation of the transformer transient is one of the indispensable qualifications for improving the performance of transformer protection, the key technique of the transformer's transient simulation is the tr...The simulation of the transformer transient is one of the indispensable qualifications for improving the performance of transformer protection, the key technique of the transformer's transient simulation is the treatment of ferromagnetic elements' loop. Thus the shapes of the primary hysteresis loop and each internal secondary hysteresis loop in the identical magnetism conducting are analyzed, and then it is proposed that there are some fractal characteristics in the relation between them. The fractal phenomenon of the ferromagnetic elements' hysteresis loop in the transformer's transient simulation is first brought forward, the mutuality between the ferromagnetic elements' primary hysteresis loop and its secondary hysteresis loops is revealed in mechanism by using the fractal theory. According to the iterated function system of fractal theory, the secondary hysteresis loops can be generated by the iterative calculation of the primary loop. The simulation results show the validity of this idea.展开更多
In order to study the factors that influence the air fuel ratio(A/F), the amplitude and frequency of A/F fluctuation, to reform the control strategy, and to improve the efficiency of three way catalyst(TWC), a model...In order to study the factors that influence the air fuel ratio(A/F), the amplitude and frequency of A/F fluctuation, to reform the control strategy, and to improve the efficiency of three way catalyst(TWC), a model of closed loop control system including the engine, air fuel mixing and transportation, oxygen sensor and controller, etc., is developed. Various factors that influence the A/F control are studied by simulation. The simulation results show that the reference voltage of oxygen sensor will influence the mean value of A/F ratio, the controller parameters will influence the amplitude of A/F fluctuation, and the operating conditions of the engine determine the frequency of A/F fluctuations, the amplitude of A/F fluctuation can be reduced to within demanded values by logical selection of the signal acquisition method and controller parameters. Higher A/F fluctuation frequency under high speed and load can be reduced through software delay in the controller. The A/F closed loop control system based on the simulation results, accompanied with a rare earth element TWC, gives a better efficiency of conversion against harmful emissions.展开更多
An electric vehicle simulation system with battery in the loop（BIL） is described in this paper.Virtual models are used for the other parts of power train including the electric motor/controller,transmission and vehi...An electric vehicle simulation system with battery in the loop（BIL） is described in this paper.Virtual models are used for the other parts of power train including the electric motor/controller,transmission and vehicle dynamics,which allows the easy change of system parameters and rapid evaluation of vehicle and battery performance for different vehicle configurations.Tests were conducted using the system and the measurements（voltage and current,efficiency） obtained from the real battery were compared with those obtained from a standard nominal model of the battery.The results indicate that the measured voltage and current between the real battery and those obtained from the model are significantly different.Additionally,it is expected that the difference will increase significantly as the battery ages.展开更多
For the research of mobile Ad hoc network (MANET), hardware in the loop simulation (HILS) is introduced to improve simulation fidelity. The architectures and frameworks of HILS system are discussed. Based on HILS and ...For the research of mobile Ad hoc network (MANET), hardware in the loop simulation (HILS) is introduced to improve simulation fidelity. The architectures and frameworks of HILS system are discussed. Based on HILS and QualNet network simulator, two kinds of simulation frameworks for MANET multicast emergency communication network are proposed. By running simulation under this configuration and doing experiments with on-demand multicast routing protocol (ODMRP), unicast and multicast functions of this protocol are tested. Research results indicate that HILS method can effectively reduce the difficulty of system modeling and improve precision of simulation, and can further accelerate transition from design to system deployment.展开更多
An investigation into the aircraft flight simulation and control system is presented in this paper. The study was firstly focused on the establishment of an integrated hardware-in-the-loop（HITL） platform for aircraf...An investigation into the aircraft flight simulation and control system is presented in this paper. The study was firstly focused on the establishment of an integrated hardware-in-the-loop（HITL） platform for aircraft flight simulation based on MATLAB/Simulink ＋ dSPACE. The platform combines the abundant software and hardware resources of dSPACE simulation platform to simulate the flight attitude of an aircraft in six-DOF （ degree of freedom） motion. Based on the platform, the study was then focused on the flight numerical simulation by taking a loitering aerial vehicle as an example. An aircraft mathematical model was created for a modular design and off-line numerical simulation based on MATLAB/Simulink. Finally, the study was focused on the control system design of the loitering aerial vehicle and conduct of an HITL simulation experiment for the vehicle pitch control. The experiment verifies the system design and control effectiveness. Research results show that the dSPACE simulation system provides a real time good experimental platform to improve the efficiency of study and development of a flight control system.展开更多
By building a turbine charged diesel engine model and a proportional electromagnet-rack model in Matlab/Simulink and using dSPACE,a hardware-in-loop(HIL) simulation platform for the electronic governor is constructed....By building a turbine charged diesel engine model and a proportional electromagnet-rack model in Matlab/Simulink and using dSPACE,a hardware-in-loop(HIL) simulation platform for the electronic governor is constructed.A developed electronic governor is simulated in this platform.The comparison between the experiment and simulation results indicates that the built models can meet the HIL requirements.The control parameters obtained from virtual calibration and the control algorithm validated by HIL simulation can be applied in real bench experiments directly.展开更多
Three-dimensional simulations of ferroelectric hysteresis and butterfly loops are carried out based on solving the time dependent Ginzburg-Landau equations using a finite volume method. The influence of externally mec...Three-dimensional simulations of ferroelectric hysteresis and butterfly loops are carried out based on solving the time dependent Ginzburg-Landau equations using a finite volume method. The influence of externally mechanical loadings with a tensile strain and a compressive strain on the hysteresis and butterfly loops is studied numerically. Different from the traditional finite element and finite difference methods, the finite volume method is applicable to simulate the ferroelectric phase transitions and properties of ferroelectric materials even for more realistic and physical problems.展开更多
We apply the hybrid Monte Carlo （HMC） micromagnetie method to FeCo soft magnetic polycrystalline films and test the new method by comparing with the result worked out by micromagnetics using Landau Lifshitz-Gilbert ...We apply the hybrid Monte Carlo （HMC） micromagnetie method to FeCo soft magnetic polycrystalline films and test the new method by comparing with the result worked out by micromagnetics using Landau Lifshitz-Gilbert equations, and the magnetic properties of FeCo films are understood better by carefully considering the effects of polycrystalline microstructures. The hysteresis loops of the FeCo film from low temperature up to 1100K are simulated by the new HMC micromagnetic method.展开更多
To evaluate the software behavior of the electronic control unit （ECU） of automotive electrical parking brake （EPB）, a software- in-the-loop （SiL） simulation system is built. The EPB is simulated by ARX （auto-r...To evaluate the software behavior of the electronic control unit （ECU） of automotive electrical parking brake （EPB）, a software- in-the-loop （SiL） simulation system is built. The EPB is simulated by ARX （auto-regressive with auxiliary input） model, ARMAX （auto-regressive moving average with auxiliary input） model, and NNARMAX （neural network ARMAX） model. By system identification, the ARX（3,4,2）, ARX（4,4,2）, ARMAX（3,3,1,1）, and ARMAX（4,4,3,2） models are derived. Validation results show that the four-order ARMAX model and the NNARMAX model better simulate the actuator of the EPB.展开更多
Hysteresis loops and energy products have been calculated systematically by a three-dimensional （3D） software OOMMF for Sm-Co/α-Fe/Sm-Co trilayers with various thicknesses and β, where β is the angle between the ...Hysteresis loops and energy products have been calculated systematically by a three-dimensional （3D） software OOMMF for Sm-Co/α-Fe/Sm-Co trilayers with various thicknesses and β, where β is the angle between the easy axis and the field applied perpendicular to the film plane. It is found that trilayers with a perpendicular anisotropy possess considerably larger coercivities and smaller remanences and energy products compared with those with an in-plane anisotropy. Increase of β leads to a fast decrease of the maximum energy product as well as the drop of both remanence and coercivity. Such a drop is much faster than that in the single-phased hard material, which can explain the significant discrepancy between the experiment and the theoretical energy products. Some modeling techniques have been utilized with spin check procedures performed, which yield results in good agreement with the one-dimensional （1D） analytical and experimental data, justifying our calculations. Further, the calculated nucleation fields according to the 3D calculations are larger than those based on the 1D model, whereas the corresponding coercivity is smaller, leading to more square hysteresis loops and better agreement between experimental data and the theory.展开更多
In order to study the basic characteristics of gas flow field in the atomizing chamber near the nozzle outlet of the vortical loop slit atomizer and its influence mechanism on clogging phenomenon,the computational flu...In order to study the basic characteristics of gas flow field in the atomizing chamber near the nozzle outlet of the vortical loop slit atomizer and its influence mechanism on clogging phenomenon,the computational fluid dynamics(CFD)software Fluent is used to conduct a numerical simulation of the gas flow field in the atomizing chamber near the nozzle outlet of this atomizer under different annular slit widths,different atomization gas pressures and different protrusion lengths of the melt delivery tube. The results show that under atomization gas pressure p=4.5 MPa,the greater the annular slit width D,the lower the static temperature near the central hole outlet at the front end of the melt delivery tube,and the smaller the aspirating pressure at the front end of the melt delivery tube. These features can effectively prevent the occurrence of the clogging phenomenon of metallic melt. Under an annular slit width of D=1.2 mm,when the atomization gas pressure satisfies 1 MPa ≤ p ≤ 2 MPa and increases gradually,the aspirating pressure at the front end of the melt delivery tube will decline rapidly. This can prevent the clogging phenomenon of metallic melt. However,when the atomization gas pressure p >2 MPa,the greater the atomization gas pressure,the lower the static temperature near the central hole outlet at the front end of the melt delivery tube,and the greater the aspirating pressure at the front end of the melt delivery tube. Hence,the effect of preventing the solidification-induced clogging phenomenon of metallic melt is restricted. When atomization gas pressure is p =4.5 MPa and annular slit width is D=1.2 mm,the greater the protrusion length H of the melt delivery tube,and the smaller the aspirating pressure at its front end. The static temperature near the central hole that can be observed in its front end is approximate to effectively prevent the occurrence of clogging phenomenon of metallic melt. However,because of the small aspirating pressure,the metallic melt flows into the atomizing chamber from the central hole at the front end of the melt delivery tube at an increasing speed and the gas-melt ratio in the mass flow rate is reduced,which is not conducive to the improvement of atomization performance.展开更多
The inconsistency of the cells in a battery pack can affect its lifespan,safety and reliability in the electric vehicles. The balanced system is an effective technique to reduce its inconsistency and improve the opera...The inconsistency of the cells in a battery pack can affect its lifespan,safety and reliability in the electric vehicles. The balanced system is an effective technique to reduce its inconsistency and improve the operating performance. A hybrid equilibrium strategy based on decision combing battery state-of-charge（ SOC） and voltage has been proposed. The battery SOC is estimated through an improved least squares method. An equalization hardware in loop（ HIL） platform has been constructed. Based on this HIL platform,equilibrium strategy has been verified under the constant-current-constant-voltage（ CCCV） and dynamicstresstest（ DST） conditions. Experimental results indicate that the proposed hybrid equalization strategy can achieve good balance effect and avoid the overcharge and over-discharge of the battery pack at the same time.展开更多
We present a theoretical study of the magnetic properties of the lanthanum copper manganate double perovskite La2CuMnO6 ceramic,using Monte Carlo simulations.We analyze and discuss the ground state phase diagrams in d...We present a theoretical study of the magnetic properties of the lanthanum copper manganate double perovskite La2CuMnO6 ceramic,using Monte Carlo simulations.We analyze and discuss the ground state phase diagrams in different planes to show the effect of every physical parameter.Based on the Monte Carlo simulations,which combine Metropolis algorithm and Ising model,we explore the thermal behavior of the total magnetization and susceptibility.We also present and discuss the influence of physical parameters such as the external magnetic field,the exchange coupling interactions between magnetic atoms,and the exchange magnetic field on the magnetization of the system.Moreover,the critical temperature of the system is about Tc=70 K,in agreement with the experimental value.Finally,the hysteresis loops of La2CuMnO6 are discussed.展开更多
In wheel–rail adhesion studies,most of the test rigs used are simplified designs such as a single wheel or wheelset,but the results may not be accurate.Alternatively,representing the complex system by using a full ve...In wheel–rail adhesion studies,most of the test rigs used are simplified designs such as a single wheel or wheelset,but the results may not be accurate.Alternatively,representing the complex system by using a full vehicle model provides accurate results but may incur complexity in design.To trade off accuracy over complexity,a bogie model can be the optimum selection.Furthermore,only a real-time model can replicate its physical counterpart in the time domain.Developing such a model requires broad expertise and appropriate software and hardware.A few published works are available which deal with real-time modeling.However,the influence of the control system has not been included in those works.To address these issues,a real-time scaled bogie test rig including the control system is essential.Therefore,a 1:4 scaled bogie roller rig is developed to study the adhesion between wheel and roller contact.To compare the performances obtained from the scaled bogie test rig and to expand the test applications,a numerical simulation model of that scaled bogie test rig is developed using Gensys multibody software.This model is the complete model of the test rig which delivers more precise results.To exactly represent the physical counterpart system in the time domain,a real-time scaled bogie test rig(RT-SBTR)is developed after four consecutive stages.Then,to simulate the RT-SBTR to solve the internal state equations and functions representing the physical counterpart system in rigs used are simplified designs such as a single wheel or wheelset,but the results may not be accurate.Alternatively,representing the complex system by using a full vehicle model provides accurate results but may incur complexity in design.To trade off accuracy over complexity,a bogie model can be the optimum selection.Furthermore,only a real-time model can replicate its physical counterpart in the time domain.Developing such a model requires broad expertise and appropriate software and hardware.A few published works are available which deal with real-time modeling.However,the influence of the control system has not been included in those works.To address these issues,a real-time scaled bogie test rig including the control system is essential.Therefore,a 1:4 scaled bogie roller rig is developed to study the adhesion between wheel and roller contact.To compare the performances obtained from the scaled bogie test rig and to expand the test applications,a numerical simulation model of that scaled bogie test rig is developed using Gensys multibody software.This model is the complete model of the test rig which delivers more precise results.To exactly represent the physical counterpart system in the time domain,a real-time scaled bogie test rig(RT-SBTR)is developed after four consecutive stages.Then,to simulate the RT-SBTR to solve the internal state equations and functions representing the physical counterpart system in equal or less than actual time,the real-time simulation environment is prepared in two stages.To such end,the computational time improved from 4 times slower than real time to 2 times faster than real time.Finally,the real-time scaled bogie model is also incorporated with the braking control system which slightly reduces the computational performances without affecting real-time capability.展开更多
A hardware-software co-simulation method for system on chip (SOC) design is discussed. It is based on an instruction set simulator (ISS) and an event-driven hardware simulator, and a bus interface model that is descri...A hardware-software co-simulation method for system on chip (SOC) design is discussed. It is based on an instruction set simulator (ISS) and an event-driven hardware simulator, and a bus interface model that is described in C language provides the interface between the two. The bus interface model and the ISS are linked into a singleton program--the software simulator, which communicate with the hardware simulator through Windows sockets. The implementation of the bus interface model and the synchronization between hardware and software simulator are discussed in detail. Co-simulation control of the hardware simulator is also discussed.展开更多
A loop modeling method, adaptive simulated annealing, for ab initio prediction of protein loop structures, as an optimization problem of searching the global minimum of a given energy function, is proposed. An interfa...A loop modeling method, adaptive simulated annealing, for ab initio prediction of protein loop structures, as an optimization problem of searching the global minimum of a given energy function, is proposed. An interface-friendly toolbox—LoopModeller in Windows and Linux systems, VC++ and OpenGL environments is developed for analysis and visualization. Simulation results of three short-chain neurotoxins modeled by LoopModeller show that the method proposed is fast and efficient.展开更多
基金the Ministerial Level Advanced Research Foundation
文摘In the large-scale distributed hardware-in-the-loop radar simulation system based on HLA, a new solution of processing after acquisition is proposed, which separates the software subsystem from the hardware jammer subsystem by a response database, so as to settle the problem, that the software subsystem can not meet the real-time need of the hardware, with very little increment of code. And the data completeness and feasibility of this solution are discussed.
基金Supported by the National Natural Science Foundation of China (61101129)Specialized Research Fund for the Doctoral Program of Higher Education(20091101110019)
文摘To enhance the fidelity and accuracy of the simulation of communication networks,hardware-in-the-loop（HITL） simulation was employed.HITL simulation methods was classified into three categories,of which the merits and shortages were compared.Combing system-in-the-loop（SITL） simulation principle with high level architecture（HLA）,an HITL simulation model of asynchronous transfer mode（ATM） network was constructed.The throughput and end-to-end delay of all-digital simulation and HITL simulation was analyzed,which showed that HITL simulation was more reliable and effectively improved the simulation credibility of communication network.Meanwhile,HLA-SITL method was fast and easy to achieve and low-cost during design lifecycle.Thus,it was a feasible way to research and analyze the large-scale network.
基金Sponsored by the Ministerial Level Advanced Research(10660060220)
文摘A hardware-in-the-loop simulating platform is developed to avoid designing defects caused by the complicated logical structure and multiple-functional buildup of the dectronic control unit（ECU）in modem diesel engines, and to diminish potential damages on components or human exposure to dangers in R＆D en- deavor. This plat-form consists of a computer installed with software Matlab/Simulink/RTW and dSPACE/ ControlDesk; a diesel engine ECU, and a dSPACE autobox which runs a real-time diesel engine model. A typical model of diesel engine with turbocharger and intercooler is presented. Based on this model our research is carried out with a real ECU to test its software control strategies. Results show that by using the diesel engine model downloaded inside, the hardware-in-the-loop platform can simulate diesel engine＇s working conditions and generate all kinds of sensor signals which ECU needs on a real-time basis. So the ECU control strategies can be validated and relevant parameters roughly calibrated.
文摘The simulation of the transformer transient is one of the indispensable qualifications for improving the performance of transformer protection, the key technique of the transformer's transient simulation is the treatment of ferromagnetic elements' loop. Thus the shapes of the primary hysteresis loop and each internal secondary hysteresis loop in the identical magnetism conducting are analyzed, and then it is proposed that there are some fractal characteristics in the relation between them. The fractal phenomenon of the ferromagnetic elements' hysteresis loop in the transformer's transient simulation is first brought forward, the mutuality between the ferromagnetic elements' primary hysteresis loop and its secondary hysteresis loops is revealed in mechanism by using the fractal theory. According to the iterated function system of fractal theory, the secondary hysteresis loops can be generated by the iterative calculation of the primary loop. The simulation results show the validity of this idea.
文摘In order to study the factors that influence the air fuel ratio(A/F), the amplitude and frequency of A/F fluctuation, to reform the control strategy, and to improve the efficiency of three way catalyst(TWC), a model of closed loop control system including the engine, air fuel mixing and transportation, oxygen sensor and controller, etc., is developed. Various factors that influence the A/F control are studied by simulation. The simulation results show that the reference voltage of oxygen sensor will influence the mean value of A/F ratio, the controller parameters will influence the amplitude of A/F fluctuation, and the operating conditions of the engine determine the frequency of A/F fluctuations, the amplitude of A/F fluctuation can be reduced to within demanded values by logical selection of the signal acquisition method and controller parameters. Higher A/F fluctuation frequency under high speed and load can be reduced through software delay in the controller. The A/F closed loop control system based on the simulation results, accompanied with a rare earth element TWC, gives a better efficiency of conversion against harmful emissions.
文摘An electric vehicle simulation system with battery in the loop（BIL） is described in this paper.Virtual models are used for the other parts of power train including the electric motor/controller,transmission and vehicle dynamics,which allows the easy change of system parameters and rapid evaluation of vehicle and battery performance for different vehicle configurations.Tests were conducted using the system and the measurements（voltage and current,efficiency） obtained from the real battery were compared with those obtained from a standard nominal model of the battery.The results indicate that the measured voltage and current between the real battery and those obtained from the model are significantly different.Additionally,it is expected that the difference will increase significantly as the battery ages.
文摘For the research of mobile Ad hoc network (MANET), hardware in the loop simulation (HILS) is introduced to improve simulation fidelity. The architectures and frameworks of HILS system are discussed. Based on HILS and QualNet network simulator, two kinds of simulation frameworks for MANET multicast emergency communication network are proposed. By running simulation under this configuration and doing experiments with on-demand multicast routing protocol (ODMRP), unicast and multicast functions of this protocol are tested. Research results indicate that HILS method can effectively reduce the difficulty of system modeling and improve precision of simulation, and can further accelerate transition from design to system deployment.
基金Sponsored by the Ministerial Level Advanced Research Foundation(A26020060253)
文摘An investigation into the aircraft flight simulation and control system is presented in this paper. The study was firstly focused on the establishment of an integrated hardware-in-the-loop（HITL） platform for aircraft flight simulation based on MATLAB/Simulink ＋ dSPACE. The platform combines the abundant software and hardware resources of dSPACE simulation platform to simulate the flight attitude of an aircraft in six-DOF （ degree of freedom） motion. Based on the platform, the study was then focused on the flight numerical simulation by taking a loitering aerial vehicle as an example. An aircraft mathematical model was created for a modular design and off-line numerical simulation based on MATLAB/Simulink. Finally, the study was focused on the control system design of the loitering aerial vehicle and conduct of an HITL simulation experiment for the vehicle pitch control. The experiment verifies the system design and control effectiveness. Research results show that the dSPACE simulation system provides a real time good experimental platform to improve the efficiency of study and development of a flight control system.
文摘By building a turbine charged diesel engine model and a proportional electromagnet-rack model in Matlab/Simulink and using dSPACE,a hardware-in-loop(HIL) simulation platform for the electronic governor is constructed.A developed electronic governor is simulated in this platform.The comparison between the experiment and simulation results indicates that the built models can meet the HIL requirements.The control parameters obtained from virtual calibration and the control algorithm validated by HIL simulation can be applied in real bench experiments directly.
基金Supported by the Research Starting Funds for Imported Talents of Ningxia University under Grant No BQD2012011
文摘Three-dimensional simulations of ferroelectric hysteresis and butterfly loops are carried out based on solving the time dependent Ginzburg-Landau equations using a finite volume method. The influence of externally mechanical loadings with a tensile strain and a compressive strain on the hysteresis and butterfly loops is studied numerically. Different from the traditional finite element and finite difference methods, the finite volume method is applicable to simulate the ferroelectric phase transitions and properties of ferroelectric materials even for more realistic and physical problems.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51171086 and 51371101
文摘We apply the hybrid Monte Carlo （HMC） micromagnetie method to FeCo soft magnetic polycrystalline films and test the new method by comparing with the result worked out by micromagnetics using Landau Lifshitz-Gilbert equations, and the magnetic properties of FeCo films are understood better by carefully considering the effects of polycrystalline microstructures. The hysteresis loops of the FeCo film from low temperature up to 1100K are simulated by the new HMC micromagnetic method.
基金Sichuan Province Key Discipline Con-struction for Automotive Engineering ( No.SZD0410 )Research Foundation of Xihua University (No.R0620301)
文摘To evaluate the software behavior of the electronic control unit （ECU） of automotive electrical parking brake （EPB）, a software- in-the-loop （SiL） simulation system is built. The EPB is simulated by ARX （auto-regressive with auxiliary input） model, ARMAX （auto-regressive moving average with auxiliary input） model, and NNARMAX （neural network ARMAX） model. By system identification, the ARX（3,4,2）, ARX（4,4,2）, ARMAX（3,3,1,1）, and ARMAX（4,4,3,2） models are derived. Validation results show that the four-order ARMAX model and the NNARMAX model better simulate the actuator of the EPB.
基金supported by the National Natural Science Foundation of China(Grant Nos.11074179,10747007,51331003,51371011,and 51001002)the State Key Development Program of Basic Research of China(Grant No.2010CB934600)+2 种基金the Construction Plan for Scientific Research Innovation Teams of Universities in Sichuan Province,China(Grant No.12TD008)the Beijing Municipal Natural Science Foundation,China(Grant No.2122006)Scientific Research Innovation Fund for Student in Sichuan Normal University,China
文摘Hysteresis loops and energy products have been calculated systematically by a three-dimensional （3D） software OOMMF for Sm-Co/α-Fe/Sm-Co trilayers with various thicknesses and β, where β is the angle between the easy axis and the field applied perpendicular to the film plane. It is found that trilayers with a perpendicular anisotropy possess considerably larger coercivities and smaller remanences and energy products compared with those with an in-plane anisotropy. Increase of β leads to a fast decrease of the maximum energy product as well as the drop of both remanence and coercivity. Such a drop is much faster than that in the single-phased hard material, which can explain the significant discrepancy between the experiment and the theoretical energy products. Some modeling techniques have been utilized with spin check procedures performed, which yield results in good agreement with the one-dimensional （1D） analytical and experimental data, justifying our calculations. Further, the calculated nucleation fields according to the 3D calculations are larger than those based on the 1D model, whereas the corresponding coercivity is smaller, leading to more square hysteresis loops and better agreement between experimental data and the theory.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Simulation and Test of the Flow Field of Gas Atomization Nozzle (No. 1001-KFA19184)。
文摘In order to study the basic characteristics of gas flow field in the atomizing chamber near the nozzle outlet of the vortical loop slit atomizer and its influence mechanism on clogging phenomenon,the computational fluid dynamics(CFD)software Fluent is used to conduct a numerical simulation of the gas flow field in the atomizing chamber near the nozzle outlet of this atomizer under different annular slit widths,different atomization gas pressures and different protrusion lengths of the melt delivery tube. The results show that under atomization gas pressure p=4.5 MPa,the greater the annular slit width D,the lower the static temperature near the central hole outlet at the front end of the melt delivery tube,and the smaller the aspirating pressure at the front end of the melt delivery tube. These features can effectively prevent the occurrence of the clogging phenomenon of metallic melt. Under an annular slit width of D=1.2 mm,when the atomization gas pressure satisfies 1 MPa ≤ p ≤ 2 MPa and increases gradually,the aspirating pressure at the front end of the melt delivery tube will decline rapidly. This can prevent the clogging phenomenon of metallic melt. However,when the atomization gas pressure p >2 MPa,the greater the atomization gas pressure,the lower the static temperature near the central hole outlet at the front end of the melt delivery tube,and the greater the aspirating pressure at the front end of the melt delivery tube. Hence,the effect of preventing the solidification-induced clogging phenomenon of metallic melt is restricted. When atomization gas pressure is p =4.5 MPa and annular slit width is D=1.2 mm,the greater the protrusion length H of the melt delivery tube,and the smaller the aspirating pressure at its front end. The static temperature near the central hole that can be observed in its front end is approximate to effectively prevent the occurrence of clogging phenomenon of metallic melt. However,because of the small aspirating pressure,the metallic melt flows into the atomizing chamber from the central hole at the front end of the melt delivery tube at an increasing speed and the gas-melt ratio in the mass flow rate is reduced,which is not conducive to the improvement of atomization performance.
基金Supported by the National Natural Science Foundation of China(51507012)Beijing Nova Program(Z171100001117063)
文摘The inconsistency of the cells in a battery pack can affect its lifespan,safety and reliability in the electric vehicles. The balanced system is an effective technique to reduce its inconsistency and improve the operating performance. A hybrid equilibrium strategy based on decision combing battery state-of-charge（ SOC） and voltage has been proposed. The battery SOC is estimated through an improved least squares method. An equalization hardware in loop（ HIL） platform has been constructed. Based on this HIL platform,equilibrium strategy has been verified under the constant-current-constant-voltage（ CCCV） and dynamicstresstest（ DST） conditions. Experimental results indicate that the proposed hybrid equalization strategy can achieve good balance effect and avoid the overcharge and over-discharge of the battery pack at the same time.
文摘We present a theoretical study of the magnetic properties of the lanthanum copper manganate double perovskite La2CuMnO6 ceramic,using Monte Carlo simulations.We analyze and discuss the ground state phase diagrams in different planes to show the effect of every physical parameter.Based on the Monte Carlo simulations,which combine Metropolis algorithm and Ising model,we explore the thermal behavior of the total magnetization and susceptibility.We also present and discuss the influence of physical parameters such as the external magnetic field,the exchange coupling interactions between magnetic atoms,and the exchange magnetic field on the magnetization of the system.Moreover,the critical temperature of the system is about Tc=70 K,in agreement with the experimental value.Finally,the hysteresis loops of La2CuMnO6 are discussed.
基金The authors greatly appreciate the financial support from the Rail Manufacturing Cooperative Research Centre(funded jointly by participating rail organizations and the Australian Federal Government’s Business Cooperative Research Centres Program)through Project R1.7.1-“Estimation of adhesion conditions between wheels and rails for the development of advanced braking control systems.”Tim McSweeney,Adjunct Research Fellow,Centre for Railway Engineering is thankfully acknowledged for his assistance with proofreading.
文摘In wheel–rail adhesion studies,most of the test rigs used are simplified designs such as a single wheel or wheelset,but the results may not be accurate.Alternatively,representing the complex system by using a full vehicle model provides accurate results but may incur complexity in design.To trade off accuracy over complexity,a bogie model can be the optimum selection.Furthermore,only a real-time model can replicate its physical counterpart in the time domain.Developing such a model requires broad expertise and appropriate software and hardware.A few published works are available which deal with real-time modeling.However,the influence of the control system has not been included in those works.To address these issues,a real-time scaled bogie test rig including the control system is essential.Therefore,a 1:4 scaled bogie roller rig is developed to study the adhesion between wheel and roller contact.To compare the performances obtained from the scaled bogie test rig and to expand the test applications,a numerical simulation model of that scaled bogie test rig is developed using Gensys multibody software.This model is the complete model of the test rig which delivers more precise results.To exactly represent the physical counterpart system in the time domain,a real-time scaled bogie test rig(RT-SBTR)is developed after four consecutive stages.Then,to simulate the RT-SBTR to solve the internal state equations and functions representing the physical counterpart system in rigs used are simplified designs such as a single wheel or wheelset,but the results may not be accurate.Alternatively,representing the complex system by using a full vehicle model provides accurate results but may incur complexity in design.To trade off accuracy over complexity,a bogie model can be the optimum selection.Furthermore,only a real-time model can replicate its physical counterpart in the time domain.Developing such a model requires broad expertise and appropriate software and hardware.A few published works are available which deal with real-time modeling.However,the influence of the control system has not been included in those works.To address these issues,a real-time scaled bogie test rig including the control system is essential.Therefore,a 1:4 scaled bogie roller rig is developed to study the adhesion between wheel and roller contact.To compare the performances obtained from the scaled bogie test rig and to expand the test applications,a numerical simulation model of that scaled bogie test rig is developed using Gensys multibody software.This model is the complete model of the test rig which delivers more precise results.To exactly represent the physical counterpart system in the time domain,a real-time scaled bogie test rig(RT-SBTR)is developed after four consecutive stages.Then,to simulate the RT-SBTR to solve the internal state equations and functions representing the physical counterpart system in equal or less than actual time,the real-time simulation environment is prepared in two stages.To such end,the computational time improved from 4 times slower than real time to 2 times faster than real time.Finally,the real-time scaled bogie model is also incorporated with the braking control system which slightly reduces the computational performances without affecting real-time capability.
文摘A hardware-software co-simulation method for system on chip (SOC) design is discussed. It is based on an instruction set simulator (ISS) and an event-driven hardware simulator, and a bus interface model that is described in C language provides the interface between the two. The bus interface model and the ISS are linked into a singleton program--the software simulator, which communicate with the hardware simulator through Windows sockets. The implementation of the bus interface model and the synchronization between hardware and software simulator are discussed in detail. Co-simulation control of the hardware simulator is also discussed.
文摘A loop modeling method, adaptive simulated annealing, for ab initio prediction of protein loop structures, as an optimization problem of searching the global minimum of a given energy function, is proposed. An interface-friendly toolbox—LoopModeller in Windows and Linux systems, VC++ and OpenGL environments is developed for analysis and visualization. Simulation results of three short-chain neurotoxins modeled by LoopModeller show that the method proposed is fast and efficient.
