Beacuse the practical mathematic model of rolling process can't be built accurately,this paper established an expert system to control the rolling steels' gauge by adjusting the setup roll open, which combined...Beacuse the practical mathematic model of rolling process can't be built accurately,this paper established an expert system to control the rolling steels' gauge by adjusting the setup roll open, which combined the experience of theoreticians and operators. The system applied the expression method of rule-skeleton+rule-body', and selected an appropriate non-exact reference model and self-study algorithm. The whole system, including auxiliary routes, is designed in Borland C++. Some experiments on this system have been done, and a good result has been achieved.展开更多
The dynamic responses of suspension system of a vehicle travelling at varying speeds are generally nonstationary random processes,and the non-stationary random analysis has become an important and complex problem in v...The dynamic responses of suspension system of a vehicle travelling at varying speeds are generally nonstationary random processes,and the non-stationary random analysis has become an important and complex problem in vehicle ride dynamics in the past few years.This paper proposes a new concept,called dynamic frequency domain(DFD),based on the fact that the human body holds different sensitivities to vibrations at different frequencies,and applies this concept to the dynamic assessment on non-stationary vehicles.The study mainly includes two parts,the first is the input numerical calculation of the front and the rear wheels,and the second is the dynamical response analysis of suspension system subjected to non-stationary random excitations.Precise time integration method is used to obtain the vertical acceleration of suspension barycenter and the pitching angular acceleration,both root mean square(RMS)values of which are illustrated in different accelerating cases.The results show that RMS values of non-stationary random excitations are functions of time and increase as the speed increases at the same time.The DFD of vertical acceleration is finally analyzed using time-frequency analysis technique,and the conclusion is obviously that the DFD has a trend to the low frequency region,which would be significant reference for active suspension design under complex driving conditions.展开更多
Modeling of welding process by robotic vision is basically a theoretical problem, means mainly on physical problem, and also technological problem. To obtain a good model of welding process by robotic vision, theoreti...Modeling of welding process by robotic vision is basically a theoretical problem, means mainly on physical problem, and also technological problem. To obtain a good model of welding process by robotic vision, theoretical researches are required but also constant experimental researches of several welding processes. Until today researches of welding processes has been based on empirical and detailed experimentation. This paper presents welding process by robotic and automation points of view with application of new technologies. Welding robotic system has been designed with possibility to control and inspect this process. Parameters that should be controlled during the process have been identified to reach desired quality. Figure of control system of welding process by robotic vision is given in this paper.展开更多
The necessi ty of product oriented integrated computer aided process planning (CAPP) is analy zed, and the system architecture and the main functions are described in detail. The key issues of the system, such as the ...The necessi ty of product oriented integrated computer aided process planning (CAPP) is analy zed, and the system architecture and the main functions are described in detail. The key issues of the system, such as the product oriented process planning me thod, the human machine cooperation in process planning, the generation of manu facture bill of material (MBOM) and the dynamic data exchanging technology betwe en CAPP and enterprise resource planning (ERP), are discussed. The CAPP system h as been applied at a CIMS environment corporation successfully.展开更多
The oxidation of Hg^0 by Pulse Corona Induced Plasma Chemical Process (PPCP) was investigated through changing discharge voltage, pulse frequency and gas compositions. Experimental results indicate that active radic...The oxidation of Hg^0 by Pulse Corona Induced Plasma Chemical Process (PPCP) was investigated through changing discharge voltage, pulse frequency and gas compositions. Experimental results indicate that active radicals including O, O3 and OH can contribute to the oxidation of elemental mercury. 10 kV is the onset voltage, and the higher voltage the better removal efficiency. While with the increase of pulse frequency, the Hg^0 concentration falls rapidly at first but then rises rapidly. The best oxidation condition is at 12 kV and 600-800 PPS. Adding O2 can significantly promote oxidation. With NO and SO2 existed, there is an inhibition of mercury oxidation, and NO has a greater influence. Addition of HCl can promote oxidation slightly but affect the initial concentration of mercury significantly. Little moisture content can promote oxidation, while too much H2O can not only resist the oxidation, but also affect the initial concentration of mercury. The mercury oxidation rate can increase to 97.95% at 12 kV/800 PPS with the system of 10% 02/3% H2O/50 ppm HCI. However, mercury oxidation efficiency can reduce down to 20% with 100 ppm NO added.展开更多
The ventilation system plays an essential role in underground workings, and improvements in dilution effect to stochastic methane build-up at cul-de-sac of a coalmine require the installation of mixed ventilation syst...The ventilation system plays an essential role in underground workings, and improvements in dilution effect to stochastic methane build-up at cul-de-sac of a coalmine require the installation of mixed ventilation system. For 4-12-1 I N02.8A centrifugal ventilation fan, the characteristic operating function of its mixed ventilation system is calculated from ventilation quantity and total pressure in the actual working status. At cul-de-sac of the reference coalmine, the evolution of methane concentration is a compound Poisson process and equivalent to a Brownian motion for Gaussian distributed increments. Solution of stochastic differential equation driven by mixed ventilation system, with dilution equation for its closure, provides parameters of mine ventilation system for keeping methane concentration within the permissible limit at cul-de-sac of the reference coalmine. These results intend to shed some light on application of blowing-sucking mixed ventilation systems in underground workings, and establish stochastic trends to consider methane control in coalmines.展开更多
Induction motor is used in many applications to drive an electromechanical system. Transients of the motor torque and speed are outlined by the inertia of rotating rotor. The paper deals with influence of rotor inerti...Induction motor is used in many applications to drive an electromechanical system. Transients of the motor torque and speed are outlined by the inertia of rotating rotor. The paper deals with influence of rotor inertia to transients of motor speed. The method of speed control measurement and experimental equipment is discussed. Simulation and experimental results are compared.展开更多
In view of its huge installed capacity and very complex transmission system,the design process of China's Three Gorges Hydropower Station had been repeatedly demonstrated for more than ten years.The smooth constru...In view of its huge installed capacity and very complex transmission system,the design process of China's Three Gorges Hydropower Station had been repeatedly demonstrated for more than ten years.The smooth construction,bringing into production and operation show that the planning scheme for Three Gorges power transmission project is successful.In this paper the design course of Three Gorges power transmission system is retrospected;the main planning schemes for Three Gorges power transmission system are reviewed;and the design results in different design stages are summarized.展开更多
The induction motor system with fluctuating potential loads is a non-linear complex electro-mechanical system.With beam pumping motors as an example,this paper proposes a multiple factor non-linear mathematical model ...The induction motor system with fluctuating potential loads is a non-linear complex electro-mechanical system.With beam pumping motors as an example,this paper proposes a multiple factor non-linear mathematical model to study the operating performance of the induction motor system.This model consists of non-linear time varying electromagnetic field equations,mechanical wave equations of sucker rods and non-linear coupling equation of reducer and four-bar linkage.The equations are numerically solved by combining time-step finite element method(TS-FEM),finite difference method(FDM),a linear dimension reduction method and the Newton-Raphson method.Simulation results,which are validated by experiments,reveal the influence of the fluctuating potential load on magnetic field distributions,stator and rotor currents,the input power and the power factor.The model and simulation results provide theoretical and technical supports for subsequent researches on model simplification and energy saving technologies.展开更多
In order to recognize the different operating conditions of a distributed and complex electromechanical system in the process industry,this work proposed a novel method of condition recognition by combining complex ne...In order to recognize the different operating conditions of a distributed and complex electromechanical system in the process industry,this work proposed a novel method of condition recognition by combining complex network theory with phase space reconstruction.First,a condition-space with complete information was reconstructed based on phase space reconstruction,and each condition in the space was transformed into a node of a complex network.Second,the limited penetrable visibility graph method was applied to establish an undirected and un-weighted complex network for the reconstructed condition-space.Finally,the statistical properties of this network were calculated to recognize the different operating conditions.A case study of a real chemical plant was conducted to illustrate the analysis and application processes of the proposed method.The results showed that the method could effectively recognize the different conditions of electromechanical systems.A complex electromechanical system can be studied from the systematic and cyber perspectives,and the relationship between the network structure property and the system condition can also be analyzed by utilizing the proposed method.展开更多
Consider a system where units have random magnitude entering according to a homogeneous or nonhomogeneous Poisson process, while in the system, a unit's magnitude may change with time. In this paper, the authors obta...Consider a system where units have random magnitude entering according to a homogeneous or nonhomogeneous Poisson process, while in the system, a unit's magnitude may change with time. In this paper, the authors obtain some results for the limiting behavior of the sum process of all unit magnitudes present in the system at time t.展开更多
Thick SU8 microstructures with high aspect ratio and good side wall quality were fabricated by ultraviolet (UV) lithography, and the processing parameters were comprehensively studied. It proves that the adhesion of...Thick SU8 microstructures with high aspect ratio and good side wall quality were fabricated by ultraviolet (UV) lithography, and the processing parameters were comprehensively studied. It proves that the adhesion of SU8 on silicon (Si) substrates is influenced by Si-OH on the surface, and can be improved by the HF treatment. Cracks and de- lamination are caused by large internal stress during fabrication process, and are significantly influenced by soft bake and post-exposure bake processes. The internal stress is reduced by a low post-exposure bake exposure tem- perature of 85 ℃ for 40 rain. A three-step soft bake enhances the reflowing ofSU8 photoresist, and results in uni- form surface and less air bubbles. The vertical side wall is obtained with the optimized exposure dose of 800 mJ/cm2 for the thickness of 160 μm. Using the optimized fabrication process combined with a proper structure design, dense SU8 micro pillars are achieved with the aspect ratio of 10 and the taper angle of 89.86°. Finally, some possible ap- plications of SU8 in micro-electromechanical system (MEMS) device are developed and demonstrated.展开更多
We study a production-inventory system having a machine, a storage facility. The demand for the product is governed by an Erlangian demand arrival process, where demand sizes are independent and identically distribute...We study a production-inventory system having a machine, a storage facility. The demand for the product is governed by an Erlangian demand arrival process, where demand sizes are independent and identically distributed random variables. A two-criticalnumber policy (m, M) is used to control a machine's setups and shutdowns, namely, a machine is shut down whenever the inventory level reaches M, and resumes operating only when the inventory level falls below the critical number m(m ≤ M). We obtain the steady state distribution of the inventory process and some performance measures of the process.展开更多
文摘Beacuse the practical mathematic model of rolling process can't be built accurately,this paper established an expert system to control the rolling steels' gauge by adjusting the setup roll open, which combined the experience of theoreticians and operators. The system applied the expression method of rule-skeleton+rule-body', and selected an appropriate non-exact reference model and self-study algorithm. The whole system, including auxiliary routes, is designed in Borland C++. Some experiments on this system have been done, and a good result has been achieved.
基金This work was supported by the National Natural Science Foundation of China(No.51705205)。
文摘The dynamic responses of suspension system of a vehicle travelling at varying speeds are generally nonstationary random processes,and the non-stationary random analysis has become an important and complex problem in vehicle ride dynamics in the past few years.This paper proposes a new concept,called dynamic frequency domain(DFD),based on the fact that the human body holds different sensitivities to vibrations at different frequencies,and applies this concept to the dynamic assessment on non-stationary vehicles.The study mainly includes two parts,the first is the input numerical calculation of the front and the rear wheels,and the second is the dynamical response analysis of suspension system subjected to non-stationary random excitations.Precise time integration method is used to obtain the vertical acceleration of suspension barycenter and the pitching angular acceleration,both root mean square(RMS)values of which are illustrated in different accelerating cases.The results show that RMS values of non-stationary random excitations are functions of time and increase as the speed increases at the same time.The DFD of vertical acceleration is finally analyzed using time-frequency analysis technique,and the conclusion is obviously that the DFD has a trend to the low frequency region,which would be significant reference for active suspension design under complex driving conditions.
文摘Modeling of welding process by robotic vision is basically a theoretical problem, means mainly on physical problem, and also technological problem. To obtain a good model of welding process by robotic vision, theoretical researches are required but also constant experimental researches of several welding processes. Until today researches of welding processes has been based on empirical and detailed experimentation. This paper presents welding process by robotic and automation points of view with application of new technologies. Welding robotic system has been designed with possibility to control and inspect this process. Parameters that should be controlled during the process have been identified to reach desired quality. Figure of control system of welding process by robotic vision is given in this paper.
文摘The necessi ty of product oriented integrated computer aided process planning (CAPP) is analy zed, and the system architecture and the main functions are described in detail. The key issues of the system, such as the product oriented process planning me thod, the human machine cooperation in process planning, the generation of manu facture bill of material (MBOM) and the dynamic data exchanging technology betwe en CAPP and enterprise resource planning (ERP), are discussed. The CAPP system h as been applied at a CIMS environment corporation successfully.
文摘The oxidation of Hg^0 by Pulse Corona Induced Plasma Chemical Process (PPCP) was investigated through changing discharge voltage, pulse frequency and gas compositions. Experimental results indicate that active radicals including O, O3 and OH can contribute to the oxidation of elemental mercury. 10 kV is the onset voltage, and the higher voltage the better removal efficiency. While with the increase of pulse frequency, the Hg^0 concentration falls rapidly at first but then rises rapidly. The best oxidation condition is at 12 kV and 600-800 PPS. Adding O2 can significantly promote oxidation. With NO and SO2 existed, there is an inhibition of mercury oxidation, and NO has a greater influence. Addition of HCl can promote oxidation slightly but affect the initial concentration of mercury significantly. Little moisture content can promote oxidation, while too much H2O can not only resist the oxidation, but also affect the initial concentration of mercury. The mercury oxidation rate can increase to 97.95% at 12 kV/800 PPS with the system of 10% 02/3% H2O/50 ppm HCI. However, mercury oxidation efficiency can reduce down to 20% with 100 ppm NO added.
文摘The ventilation system plays an essential role in underground workings, and improvements in dilution effect to stochastic methane build-up at cul-de-sac of a coalmine require the installation of mixed ventilation system. For 4-12-1 I N02.8A centrifugal ventilation fan, the characteristic operating function of its mixed ventilation system is calculated from ventilation quantity and total pressure in the actual working status. At cul-de-sac of the reference coalmine, the evolution of methane concentration is a compound Poisson process and equivalent to a Brownian motion for Gaussian distributed increments. Solution of stochastic differential equation driven by mixed ventilation system, with dilution equation for its closure, provides parameters of mine ventilation system for keeping methane concentration within the permissible limit at cul-de-sac of the reference coalmine. These results intend to shed some light on application of blowing-sucking mixed ventilation systems in underground workings, and establish stochastic trends to consider methane control in coalmines.
文摘Induction motor is used in many applications to drive an electromechanical system. Transients of the motor torque and speed are outlined by the inertia of rotating rotor. The paper deals with influence of rotor inertia to transients of motor speed. The method of speed control measurement and experimental equipment is discussed. Simulation and experimental results are compared.
文摘In view of its huge installed capacity and very complex transmission system,the design process of China's Three Gorges Hydropower Station had been repeatedly demonstrated for more than ten years.The smooth construction,bringing into production and operation show that the planning scheme for Three Gorges power transmission project is successful.In this paper the design course of Three Gorges power transmission system is retrospected;the main planning schemes for Three Gorges power transmission system are reviewed;and the design results in different design stages are summarized.
基金supported by the National Natural Science Foundation of China(Grant No.51307050)
文摘The induction motor system with fluctuating potential loads is a non-linear complex electro-mechanical system.With beam pumping motors as an example,this paper proposes a multiple factor non-linear mathematical model to study the operating performance of the induction motor system.This model consists of non-linear time varying electromagnetic field equations,mechanical wave equations of sucker rods and non-linear coupling equation of reducer and four-bar linkage.The equations are numerically solved by combining time-step finite element method(TS-FEM),finite difference method(FDM),a linear dimension reduction method and the Newton-Raphson method.Simulation results,which are validated by experiments,reveal the influence of the fluctuating potential load on magnetic field distributions,stator and rotor currents,the input power and the power factor.The model and simulation results provide theoretical and technical supports for subsequent researches on model simplification and energy saving technologies.
基金supported by the National Natural Science Foundation of China (Grant by No. 51175402)
文摘In order to recognize the different operating conditions of a distributed and complex electromechanical system in the process industry,this work proposed a novel method of condition recognition by combining complex network theory with phase space reconstruction.First,a condition-space with complete information was reconstructed based on phase space reconstruction,and each condition in the space was transformed into a node of a complex network.Second,the limited penetrable visibility graph method was applied to establish an undirected and un-weighted complex network for the reconstructed condition-space.Finally,the statistical properties of this network were calculated to recognize the different operating conditions.A case study of a real chemical plant was conducted to illustrate the analysis and application processes of the proposed method.The results showed that the method could effectively recognize the different conditions of electromechanical systems.A complex electromechanical system can be studied from the systematic and cyber perspectives,and the relationship between the network structure property and the system condition can also be analyzed by utilizing the proposed method.
基金Project supported by the National Natural Science Foundation of China (No. 10571159, No. 10371109)the Specialized Research Fund for the Doctor Program of Higher Education (No. 20060335032).
文摘Consider a system where units have random magnitude entering according to a homogeneous or nonhomogeneous Poisson process, while in the system, a unit's magnitude may change with time. In this paper, the authors obtain some results for the limiting behavior of the sum process of all unit magnitudes present in the system at time t.
基金supported by the National High Technology Research and Development Program(No.2015AA042603)the Fundamental Research Funds for the Central Universities in China(Nos.106112014CDJZR160001 and 106112015CDJXY120002)
文摘Thick SU8 microstructures with high aspect ratio and good side wall quality were fabricated by ultraviolet (UV) lithography, and the processing parameters were comprehensively studied. It proves that the adhesion of SU8 on silicon (Si) substrates is influenced by Si-OH on the surface, and can be improved by the HF treatment. Cracks and de- lamination are caused by large internal stress during fabrication process, and are significantly influenced by soft bake and post-exposure bake processes. The internal stress is reduced by a low post-exposure bake exposure tem- perature of 85 ℃ for 40 rain. A three-step soft bake enhances the reflowing ofSU8 photoresist, and results in uni- form surface and less air bubbles. The vertical side wall is obtained with the optimized exposure dose of 800 mJ/cm2 for the thickness of 160 μm. Using the optimized fabrication process combined with a proper structure design, dense SU8 micro pillars are achieved with the aspect ratio of 10 and the taper angle of 89.86°. Finally, some possible ap- plications of SU8 in micro-electromechanical system (MEMS) device are developed and demonstrated.
基金This research is supported by the National Natural Science Foundation of China (No. 19871093).
文摘We study a production-inventory system having a machine, a storage facility. The demand for the product is governed by an Erlangian demand arrival process, where demand sizes are independent and identically distributed random variables. A two-criticalnumber policy (m, M) is used to control a machine's setups and shutdowns, namely, a machine is shut down whenever the inventory level reaches M, and resumes operating only when the inventory level falls below the critical number m(m ≤ M). We obtain the steady state distribution of the inventory process and some performance measures of the process.