For the purpose to facilitate development of high-speed Spindle Units (SUs) running on rolling bearings, we have developed a beam element model, algorithms, and software for computer analysis of thermal characteristic...For the purpose to facilitate development of high-speed Spindle Units (SUs) running on rolling bearings, we have developed a beam element model, algorithms, and software for computer analysis of thermal characteristics of SUs. The thermal model incorporates a model of heat generation in rolling bearings, a model of heat transfer from bearings, and models for estimation of temperature and temperature deformations of SU elements. We have carried out experimental test and made quantitative evaluation of the effect of operation conditions on friction and thermal characteristics of the SUs of grinding and turning machines of typical structures. It is found that the operation conditions make stronger effect on SU temperatures when rpm increases. A comparison between the results of analysis and experiment proves their good mutual correspondence and allows us to recommend application of the models and software developed for design and research of high-speed SUs running on rolling bearings.展开更多
The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board...The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board train control system.To conduct fault prediction for the BTM unit based on actual fault data,this study proposes a prediction method combining reliability statistics and machine learning,and achieves the fusion of prediction results from different dimensions through multi-method interactive validation.Firstly,a method for predicting equipment fault time targeting batch equipment is introduced.This method utilizes reliability statistics to construct a model of the remaining faultless operating time distribution considering uncertainty,thereby predicting the remaining faultless operating probability of the BTM unit.Secondly,considering the complexity of the BTM unit’s fault mechanism,the small sample size of fault cases,and the potential presence of multiple fault features in fault text records,an individual-oriented fault prediction method based on Bayesian-optimized Gradient Boosting Regression Tree(Bayes-GBRT)is proposed.This method achieves better prediction results compared to linear regression algorithms and random forest regression algorithms,with an average absolute error of only 0.224 years for predicting the fault time of this type of equipment.Finally,a multi-method interactive validation approach is proposed,enabling the fusion and validation of multi-dimensional results.The results indicate that the predicted fault time and the actual fault time conform to a log-normal distribution,and the parameter estimation results are basically consistent,verifying the accuracy and effectiveness of the prediction results.The above research findings can provide technical support for the maintenance and modification of BTM units,effectively reducing maintenance costs and ensuring the safe operation of high-speed railway,thus having practical engineering value for preventive maintenance.展开更多
【目的】为准确高效地分析多轴双环磁力齿轮(Multishaft Double Ring-Plate Magnetic Gears,MDRMGs)的磁力与动力学特性,改善摆线式磁力齿轮(Cycloidal Permanent Magnetic Gear,CPMG)转臂轴承工况并延长使用寿命,将磁力齿轮与机械式环...【目的】为准确高效地分析多轴双环磁力齿轮(Multishaft Double Ring-Plate Magnetic Gears,MDRMGs)的磁力与动力学特性,改善摆线式磁力齿轮(Cycloidal Permanent Magnetic Gear,CPMG)转臂轴承工况并延长使用寿命,将磁力齿轮与机械式环板齿轮相结合,设计了一种多轴双环磁力齿轮传动结构。【方法】提出一种磁场单元归类法,进而建立了高效且计及端部漏磁效应的气隙磁场及静态转矩数理模型;同时,基于Riccati传递矩阵法,建立了MDRMG偏心轴转子系统动力学模型。【结果】将磁场单元归类法与有限元法进行对比,发现二者所得的磁密度及磁力结果高度一致,但磁场单元归类法的计算耗时更短;分析还发现,环板间距的变化会影响磁场单元的归类计算及动力学模型中的集总参数,使得MDRMG的静态磁力转矩随环板间距的增加而增加,偏心轴的临界转速随环板间距的增加而减小。磁场单元归类法能够高效且准确地分析MDRMG的气隙磁场及转矩特性;同时,环板间距对MDRMGs的磁场和动力学性能有一定影响。展开更多
The application status of friction stir welding technology is introduced,and the application research of advanced FSW technology in the manufacture of high-speed electric multiple unit aluminum alloy body is analyzed,...The application status of friction stir welding technology is introduced,and the application research of advanced FSW technology in the manufacture of high-speed electric multiple unit aluminum alloy body is analyzed,including the application of traditional friction stir welding technology to a combination of a lap joint and butt joint,and butt joint of large thick plate by both sides process,also introduces bobbin-tool friction stir welding to a butt joint and three-dimensional space curved friction stir welding to T-joint. At the same time the future development trend of new FSW technology derived from traditional FSW technology in rail vehicle manufacturing industry is put forward. As the fast developing of critical technology used on railway vehicles,quick applying advanced welding technology will affect products quality,manufacturing cost and production cycle time directly,and it certainly will be one of the approaches to develop markets by all the railway vehicles manufacturing enterprises.展开更多
In this paper, the control problem of auxiliary power unit （APU） for hybrid electric vehicles is investigated. An adaptive controller is provided to achieve the coordinated control between the engine speed and the b...In this paper, the control problem of auxiliary power unit （APU） for hybrid electric vehicles is investigated. An adaptive controller is provided to achieve the coordinated control between the engine speed and the battery charging voltage. The proposed adaptive coordinated control laws for the throttle angle of the engine and the voltage of the power-converter can guarantee not only the asymptotic tracking performance of the engine speed and the regulation of the battery charging voltage, but also the robust stability of the closed loop system under external load changes. Simulation results are given to verify the performance of the proposed adaptive controller.展开更多
The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability,improving the adhesion utilization,and achieving deep energy recover...The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability,improving the adhesion utilization,and achieving deep energy recovery.There remain technical challenges mainly because of the nonlinear,uncertain,and varying features of wheel-rail contact conditions.This research analyzes the torque transmitting behavior during regenerative braking,and proposes a novel methodology to detect the wheel-rail adhesion stability.Then,applications to the wheel slip prevention during braking are investigated,and the optimal slip ratio control scheme is proposed,which is based on a novel optimal reference generation of the slip ratio and a robust sliding mode control.The proposed methodology achieves the optimal braking performancewithoutthewheel-railcontactinformation.Numerical simulation results for uncertain slippery rails verify the effectiveness of the proposed methodology.展开更多
The paper aims to defme the lawfulness （model）, by which one can reliably estimate the distribution of motor units＇ force from the moment when leg extensor muscles start to generate the force until the moment when ...The paper aims to defme the lawfulness （model）, by which one can reliably estimate the distribution of motor units＇ force from the moment when leg extensor muscles start to generate the force until the moment when the maximal level is achieved. The study included 110 participants. To assess the contractile characteristics of leg extensors, standardized equipment and standardized isometric test in sitting position with the angle of the knee joint of 125° were used. The participants were instructed to exert their maximal force as quickly as possible. Using descriptive statistics, cluster analysis and fitting the exponential model of the distribution of force of leg extensor motor units in the whole range of force generation is defined. The model has the following form： y = 0.2051e3.3855x, where y is the motor units force expressed in daN （decanewtons）, x is the time expressed in s （seconds）. It provides an understanding of the control of multivariate motor unit recruitment and distribution of their force during sports movements as well as training programming for the adoption of forms for conlrolling force distribution of motor units, the development of their maximum force and their involvement speed.展开更多
The scope of this paper is to forecast wind speed. Wind speed, temperature, wind direction, relative humidity, precipitation of water content and air pressure are the main factors make the wind speed forecasting as a ...The scope of this paper is to forecast wind speed. Wind speed, temperature, wind direction, relative humidity, precipitation of water content and air pressure are the main factors make the wind speed forecasting as a complex problem and neural network performance is mainly influenced by proper hidden layer neuron units. This paper proposes new criteria for appropriate hidden layer neuron unit’s determination and attempts a novel hybrid method in order to achieve enhanced wind speed forecasting. This paper proposes the following two main innovative contributions 1) both either over fitting or under fitting issues are avoided by means of the proposed new criteria based hidden layer neuron unit’s estimation. 2) ELMAN neural network is optimized through Modified Grey Wolf Optimizer (MGWO). The proposed hybrid method (ELMAN-MGWO) performance, effectiveness is confirmed by means of the comparison between Grey Wolf Optimizer (GWO), Adaptive Gbest-guided Gravitational Search Algorithm (GGSA), Artificial Bee Colony (ABC), Ant Colony Optimization (ACO), Cuckoo Search (CS), Particle Swarm Optimization (PSO), Evolution Strategy (ES), Genetic Algorithm (GA) algorithms, meanwhile proposed new criteria effectiveness and precise are verified comparison with other existing selection criteria. Three real-time wind data sets are utilized in order to analysis the performance of the proposed approach. Simulation results demonstrate that the proposed hybrid method (ELMAN-MGWO) achieve the mean square error AVG ± STD of 4.1379e-11 ± 1.0567e-15, 6.3073e-11 ± 3.5708e-15 and 7.5840e-11 ± 1.1613e-14 respectively for evaluation on three real-time data sets. Hence, the proposed hybrid method is superior, precise, enhance wind speed forecasting than that of other existing methods and robust.展开更多
For the purpose to improve a design quality of high-speed spindle units, we have developed mathematical models and software to simulate a rotation accuracy of spindles running on ball bearings. In order to better unde...For the purpose to improve a design quality of high-speed spindle units, we have developed mathematical models and software to simulate a rotation accuracy of spindles running on ball bearings. In order to better understand the mechanics of ball bearings, the dynamic interaction of ball bearings and spindle unit, and the influence of the bearing imperfections on the spindle rotation accuracy, we have carried out computer aided analysis and experimental studies. When doing this, we have found that the spindle rotation accuracy can vary drastically with rotational speed. The influence of bearing preload has a secondary importance. Comparison of the results of these studies has demonstrated adequacy of the models developed to the real spindle units.展开更多
文摘For the purpose to facilitate development of high-speed Spindle Units (SUs) running on rolling bearings, we have developed a beam element model, algorithms, and software for computer analysis of thermal characteristics of SUs. The thermal model incorporates a model of heat generation in rolling bearings, a model of heat transfer from bearings, and models for estimation of temperature and temperature deformations of SU elements. We have carried out experimental test and made quantitative evaluation of the effect of operation conditions on friction and thermal characteristics of the SUs of grinding and turning machines of typical structures. It is found that the operation conditions make stronger effect on SU temperatures when rpm increases. A comparison between the results of analysis and experiment proves their good mutual correspondence and allows us to recommend application of the models and software developed for design and research of high-speed SUs running on rolling bearings.
基金supported by the Integrated Rail Transit Dispatch Control and Intermodal Transport Service Technology Project(Grant No.2022YFB4300500).
文摘The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial component.Due to its unique installation position and complex environment,this unit has a higher fault rate within the on-board train control system.To conduct fault prediction for the BTM unit based on actual fault data,this study proposes a prediction method combining reliability statistics and machine learning,and achieves the fusion of prediction results from different dimensions through multi-method interactive validation.Firstly,a method for predicting equipment fault time targeting batch equipment is introduced.This method utilizes reliability statistics to construct a model of the remaining faultless operating time distribution considering uncertainty,thereby predicting the remaining faultless operating probability of the BTM unit.Secondly,considering the complexity of the BTM unit’s fault mechanism,the small sample size of fault cases,and the potential presence of multiple fault features in fault text records,an individual-oriented fault prediction method based on Bayesian-optimized Gradient Boosting Regression Tree(Bayes-GBRT)is proposed.This method achieves better prediction results compared to linear regression algorithms and random forest regression algorithms,with an average absolute error of only 0.224 years for predicting the fault time of this type of equipment.Finally,a multi-method interactive validation approach is proposed,enabling the fusion and validation of multi-dimensional results.The results indicate that the predicted fault time and the actual fault time conform to a log-normal distribution,and the parameter estimation results are basically consistent,verifying the accuracy and effectiveness of the prediction results.The above research findings can provide technical support for the maintenance and modification of BTM units,effectively reducing maintenance costs and ensuring the safe operation of high-speed railway,thus having practical engineering value for preventive maintenance.
文摘【目的】为准确高效地分析多轴双环磁力齿轮(Multishaft Double Ring-Plate Magnetic Gears,MDRMGs)的磁力与动力学特性,改善摆线式磁力齿轮(Cycloidal Permanent Magnetic Gear,CPMG)转臂轴承工况并延长使用寿命,将磁力齿轮与机械式环板齿轮相结合,设计了一种多轴双环磁力齿轮传动结构。【方法】提出一种磁场单元归类法,进而建立了高效且计及端部漏磁效应的气隙磁场及静态转矩数理模型;同时,基于Riccati传递矩阵法,建立了MDRMG偏心轴转子系统动力学模型。【结果】将磁场单元归类法与有限元法进行对比,发现二者所得的磁密度及磁力结果高度一致,但磁场单元归类法的计算耗时更短;分析还发现,环板间距的变化会影响磁场单元的归类计算及动力学模型中的集总参数,使得MDRMG的静态磁力转矩随环板间距的增加而增加,偏心轴的临界转速随环板间距的增加而减小。磁场单元归类法能够高效且准确地分析MDRMG的气隙磁场及转矩特性;同时,环板间距对MDRMGs的磁场和动力学性能有一定影响。
基金supported by Changchun Science and Technology Innovation"Double Tenth Project"(Grant No.17SS024)Technical Development Project of CRRC Changchun Railway Vehicles Co.,Ltd(Grant No.16GCZX006)
文摘The application status of friction stir welding technology is introduced,and the application research of advanced FSW technology in the manufacture of high-speed electric multiple unit aluminum alloy body is analyzed,including the application of traditional friction stir welding technology to a combination of a lap joint and butt joint,and butt joint of large thick plate by both sides process,also introduces bobbin-tool friction stir welding to a butt joint and three-dimensional space curved friction stir welding to T-joint. At the same time the future development trend of new FSW technology derived from traditional FSW technology in rail vehicle manufacturing industry is put forward. As the fast developing of critical technology used on railway vehicles,quick applying advanced welding technology will affect products quality,manufacturing cost and production cycle time directly,and it certainly will be one of the approaches to develop markets by all the railway vehicles manufacturing enterprises.
文摘In this paper, the control problem of auxiliary power unit （APU） for hybrid electric vehicles is investigated. An adaptive controller is provided to achieve the coordinated control between the engine speed and the battery charging voltage. The proposed adaptive coordinated control laws for the throttle angle of the engine and the voltage of the power-converter can guarantee not only the asymptotic tracking performance of the engine speed and the regulation of the battery charging voltage, but also the robust stability of the closed loop system under external load changes. Simulation results are given to verify the performance of the proposed adaptive controller.
基金supported by the National Natural Science Foundation of China(Grant 51305437)Guangdong Innovative Research Team Program of China(Grant201001D0104648280)
文摘The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability,improving the adhesion utilization,and achieving deep energy recovery.There remain technical challenges mainly because of the nonlinear,uncertain,and varying features of wheel-rail contact conditions.This research analyzes the torque transmitting behavior during regenerative braking,and proposes a novel methodology to detect the wheel-rail adhesion stability.Then,applications to the wheel slip prevention during braking are investigated,and the optimal slip ratio control scheme is proposed,which is based on a novel optimal reference generation of the slip ratio and a robust sliding mode control.The proposed methodology achieves the optimal braking performancewithoutthewheel-railcontactinformation.Numerical simulation results for uncertain slippery rails verify the effectiveness of the proposed methodology.
文摘The paper aims to defme the lawfulness （model）, by which one can reliably estimate the distribution of motor units＇ force from the moment when leg extensor muscles start to generate the force until the moment when the maximal level is achieved. The study included 110 participants. To assess the contractile characteristics of leg extensors, standardized equipment and standardized isometric test in sitting position with the angle of the knee joint of 125° were used. The participants were instructed to exert their maximal force as quickly as possible. Using descriptive statistics, cluster analysis and fitting the exponential model of the distribution of force of leg extensor motor units in the whole range of force generation is defined. The model has the following form： y = 0.2051e3.3855x, where y is the motor units force expressed in daN （decanewtons）, x is the time expressed in s （seconds）. It provides an understanding of the control of multivariate motor unit recruitment and distribution of their force during sports movements as well as training programming for the adoption of forms for conlrolling force distribution of motor units, the development of their maximum force and their involvement speed.
文摘The scope of this paper is to forecast wind speed. Wind speed, temperature, wind direction, relative humidity, precipitation of water content and air pressure are the main factors make the wind speed forecasting as a complex problem and neural network performance is mainly influenced by proper hidden layer neuron units. This paper proposes new criteria for appropriate hidden layer neuron unit’s determination and attempts a novel hybrid method in order to achieve enhanced wind speed forecasting. This paper proposes the following two main innovative contributions 1) both either over fitting or under fitting issues are avoided by means of the proposed new criteria based hidden layer neuron unit’s estimation. 2) ELMAN neural network is optimized through Modified Grey Wolf Optimizer (MGWO). The proposed hybrid method (ELMAN-MGWO) performance, effectiveness is confirmed by means of the comparison between Grey Wolf Optimizer (GWO), Adaptive Gbest-guided Gravitational Search Algorithm (GGSA), Artificial Bee Colony (ABC), Ant Colony Optimization (ACO), Cuckoo Search (CS), Particle Swarm Optimization (PSO), Evolution Strategy (ES), Genetic Algorithm (GA) algorithms, meanwhile proposed new criteria effectiveness and precise are verified comparison with other existing selection criteria. Three real-time wind data sets are utilized in order to analysis the performance of the proposed approach. Simulation results demonstrate that the proposed hybrid method (ELMAN-MGWO) achieve the mean square error AVG ± STD of 4.1379e-11 ± 1.0567e-15, 6.3073e-11 ± 3.5708e-15 and 7.5840e-11 ± 1.1613e-14 respectively for evaluation on three real-time data sets. Hence, the proposed hybrid method is superior, precise, enhance wind speed forecasting than that of other existing methods and robust.
文摘For the purpose to improve a design quality of high-speed spindle units, we have developed mathematical models and software to simulate a rotation accuracy of spindles running on ball bearings. In order to better understand the mechanics of ball bearings, the dynamic interaction of ball bearings and spindle unit, and the influence of the bearing imperfections on the spindle rotation accuracy, we have carried out computer aided analysis and experimental studies. When doing this, we have found that the spindle rotation accuracy can vary drastically with rotational speed. The influence of bearing preload has a secondary importance. Comparison of the results of these studies has demonstrated adequacy of the models developed to the real spindle units.
