This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/s...This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under highspeed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded.展开更多
为了达到能量转换最优化和减小机械结构的疲劳负荷的要求,基于双馈感应发电机风能转换系统建立了数学模型,提出一种双频环滑模预测优化控制方法。该方法采用双频环多目标结构,低频环引入基于ARMA(autoregressive and moving average mod...为了达到能量转换最优化和减小机械结构的疲劳负荷的要求,基于双馈感应发电机风能转换系统建立了数学模型,提出一种双频环滑模预测优化控制方法。该方法采用双频环多目标结构,低频环引入基于ARMA(autoregressive and moving average model)模型预测后的风速低频分量,采用PI控制对应于最优叶尖速度以保证其工作点运行在最优控制特性曲线上;高频环引入风速的湍流分量,将预测控制与滑模控制相结合实现系统的动态优化。仿真结果表明:双频环滑模预测控制有效避免了不确定性对系统的影响,实现了部分负荷状态下的最优控制特性跟踪,减少了控制输入量的变化量,降低了机械疲劳,保证了系统的优化稳定运行。展开更多
基金supported by the National Natural Science Foundation of China(Nos.51620105010,51675019 and 51575019)the National Basic Research Program of China(No.2014CB046402)+1 种基金the ‘‘111" Projectthe Excellence Foundation of BUAA for PhD Students
文摘This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator（LS-EHA）. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under highspeed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded.
文摘为了达到能量转换最优化和减小机械结构的疲劳负荷的要求,基于双馈感应发电机风能转换系统建立了数学模型,提出一种双频环滑模预测优化控制方法。该方法采用双频环多目标结构,低频环引入基于ARMA(autoregressive and moving average model)模型预测后的风速低频分量,采用PI控制对应于最优叶尖速度以保证其工作点运行在最优控制特性曲线上;高频环引入风速的湍流分量,将预测控制与滑模控制相结合实现系统的动态优化。仿真结果表明:双频环滑模预测控制有效避免了不确定性对系统的影响,实现了部分负荷状态下的最优控制特性跟踪,减少了控制输入量的变化量,降低了机械疲劳,保证了系统的优化稳定运行。
