为提高电励磁直线电动机(electrically excited linear motors,EELM)驱动的数控机床磁悬浮平台控制系统的性能,提出一种非线性自适应反步控制方法。研究EELM的结构与运行机理,该EELM的定子由铁心和励磁绕组组成,动子由动子铁心和电枢绕...为提高电励磁直线电动机(electrically excited linear motors,EELM)驱动的数控机床磁悬浮平台控制系统的性能,提出一种非线性自适应反步控制方法。研究EELM的结构与运行机理,该EELM的定子由铁心和励磁绕组组成,动子由动子铁心和电枢绕组组成,与数控机床进给平台固定连接驱动平台运动,励磁磁场对动子铁心的单边磁拉力实现平台的悬浮;建立EELM磁悬浮平台控制系统的数学模型与状态方程;对电励磁直线电动机磁悬浮平台运行过程中存在的不确定性扰动,设计非线性自适应反步控制器,对未知扰动进行估计,采用李雅普诺夫理论证明系统的稳定性;用MATLAB/Simulink对控制系统进行计算机仿真,验证所提方法的有效性。展开更多
由于在数控机床直线同步电动机磁悬浮系统中,直轴电流、悬浮高度与水平速度之间存在非线性耦合,以及负载扰动等不确定因素,会对控制系统产生诸多不利影响。针对该问题,提出了一种新型解耦控制方法。建立可控励磁磁悬浮直线同步电动机(co...由于在数控机床直线同步电动机磁悬浮系统中,直轴电流、悬浮高度与水平速度之间存在非线性耦合,以及负载扰动等不确定因素,会对控制系统产生诸多不利影响。针对该问题,提出了一种新型解耦控制方法。建立可控励磁磁悬浮直线同步电动机(controllable excitation linear magnetic suspension synchronous motor,CELMSSM)的数学模型;通过选取适当的状态变量得到该电动机的仿射非线性模型;在传统电流控制的基础上,利用非线性系统的微分几何理论,通过坐标变换与状态反馈,将电动机仿射非线性模型解耦线性化为直轴电流子系统、水平速度子系统以及悬浮高度子系统的3个可独立控制的线性子系统;根据最优极点配置法设计系统的控制规律,从而实现可控励磁磁悬浮直线同步电动机的动态解耦控制。最后,对控制系统进行仿真研究,结果表明通过反馈线性化控制与传统PI控制仿真对比,所提出的控制策略可使系统的动、静态性能得到显著增强。展开更多
Objective To analyze the application of real-world evidence(RWE)in the field of medicine in European Union,and provide suggestions for RWE supporting the review and approval of new drugs in China.Methods The European ...Objective To analyze the application of real-world evidence(RWE)in the field of medicine in European Union,and provide suggestions for RWE supporting the review and approval of new drugs in China.Methods The European Medicines Agency(EMA)and other databases were used to search relevant documents for analyzing the European Union’s new drug review and approval process with the support of RWE.Results and Conclusion The European Union carrying out new drug review and approval with the support of RWE has just begun.The decision-making process includes three stages such as new drug research and development,review,and approval.However,there are some challenges in data quality,research methods,evidence sufficiency,and research process of RWE supporting the European Union in reviewing and approving new drugs.At present,RWE can accurately grasp the clinical effects of drugs and improve the safety and effectiveness in the process of assisting the review and approval of new drugs.At the same time,RWE also can promote the development and application of Traditional Chinese Medicine(TCM)and help find out the potential value of TCM such as new indications.展开更多
文摘为提高电励磁直线电动机(electrically excited linear motors,EELM)驱动的数控机床磁悬浮平台控制系统的性能,提出一种非线性自适应反步控制方法。研究EELM的结构与运行机理,该EELM的定子由铁心和励磁绕组组成,动子由动子铁心和电枢绕组组成,与数控机床进给平台固定连接驱动平台运动,励磁磁场对动子铁心的单边磁拉力实现平台的悬浮;建立EELM磁悬浮平台控制系统的数学模型与状态方程;对电励磁直线电动机磁悬浮平台运行过程中存在的不确定性扰动,设计非线性自适应反步控制器,对未知扰动进行估计,采用李雅普诺夫理论证明系统的稳定性;用MATLAB/Simulink对控制系统进行计算机仿真,验证所提方法的有效性。
文摘由于在数控机床直线同步电动机磁悬浮系统中,直轴电流、悬浮高度与水平速度之间存在非线性耦合,以及负载扰动等不确定因素,会对控制系统产生诸多不利影响。针对该问题,提出了一种新型解耦控制方法。建立可控励磁磁悬浮直线同步电动机(controllable excitation linear magnetic suspension synchronous motor,CELMSSM)的数学模型;通过选取适当的状态变量得到该电动机的仿射非线性模型;在传统电流控制的基础上,利用非线性系统的微分几何理论,通过坐标变换与状态反馈,将电动机仿射非线性模型解耦线性化为直轴电流子系统、水平速度子系统以及悬浮高度子系统的3个可独立控制的线性子系统;根据最优极点配置法设计系统的控制规律,从而实现可控励磁磁悬浮直线同步电动机的动态解耦控制。最后,对控制系统进行仿真研究,结果表明通过反馈线性化控制与传统PI控制仿真对比,所提出的控制策略可使系统的动、静态性能得到显著增强。
基金Special Fund of the National Medical Products Administration’s Drug Regulatory Science Research Base-Research Institute of Drug Regulatory Science of Shenyang Pharmaceutical University(No.2020jgkx005).
文摘Objective To analyze the application of real-world evidence(RWE)in the field of medicine in European Union,and provide suggestions for RWE supporting the review and approval of new drugs in China.Methods The European Medicines Agency(EMA)and other databases were used to search relevant documents for analyzing the European Union’s new drug review and approval process with the support of RWE.Results and Conclusion The European Union carrying out new drug review and approval with the support of RWE has just begun.The decision-making process includes three stages such as new drug research and development,review,and approval.However,there are some challenges in data quality,research methods,evidence sufficiency,and research process of RWE supporting the European Union in reviewing and approving new drugs.At present,RWE can accurately grasp the clinical effects of drugs and improve the safety and effectiveness in the process of assisting the review and approval of new drugs.At the same time,RWE also can promote the development and application of Traditional Chinese Medicine(TCM)and help find out the potential value of TCM such as new indications.