磁悬浮系统的积分变结构控制

针对磁悬浮系统的非线性特性,提出一种积分变结构控制方法.搭建了磁悬浮系统的非线性数学模型,采用变结构理论设计控制器,切换函数选取时引入积分环节,并用光滑连续的饱和函数取代符号函数,减小系统的稳态误差.仿真结果验证,积分变结构控制可以有效消除抖振,当外界扰动作用时,系统具有较好的平稳性和鲁棒性.     

H infinity Control for Sandwiched Maglev Stage with Dynamic Damping

An H infinity (H∞) controller for a sandwiched maglev positioning stage is proposed. The maglev positioning stage has a special structure:a sandwiched maglev stage, consisting of repulsive linear motors and attractive linear motors, which have better levitation performance. Forces on the sandwiched maglev stage are analyzed and modeled. The positioning controller is designed based on the feedback linearized model with a dynamic damping system. The design of the H infinity controller for stage positioning is derived as a series of linear matrix inequalities (LMIs) which are efficiently solved in Matlab. The proposed controller and its effectiveness is demonstrated compared to PID method.     

磁悬浮平台电磁悬浮系统的模糊滑模控制

为实现开环不稳定且高度非线性的磁悬浮平台悬浮气隙的精确控制,采用模糊滑模控制方案,根据电磁悬浮系统的动态非线性数学模型,设计使系统状态在有限时间内到达稳定点的滑模面,通过等效控制和切换控制律实现对参数摄动和外部扰动的完全鲁棒性.根据滑模切换状态,利用模糊推理方法柔化切换控制.基于模糊滑模控制器的控制系统能够有效地削弱滑模控制抖振,并较好地抑制外部扰动,且对参数变化具有完全鲁棒性,实现磁悬浮平台的高刚度稳定悬浮.结果表明,所设计的控制系统对参数变化及周期性扰动具有很强的鲁棒性.     

Levitation mechanism modelling for maglev transportation system

A novel maglev transportation system was proposed for large travel range ultra precision motion. The system consists of a levitation subsystem and a propulsion subsystem. During the propulsion subsystem driving the moving platform along the guideway, the levitation subsystem uses six pairs of electromagnets to steadily suspend the moving platform over the guideway. The model of the levitation system, which is a typical nonlinear multi-input multi-output coupling system and has many inner nonlinear coupling characteristics, was deduced. For testifying the model, the levitation mechanism was firstly controlled by proportional-integral-differential (PID) control, and then a lot of input-output data were collected for model parameter identification. The least-square parameter identification method was used. The identification results prove that the model is feasible and suitable for the real system.     

层叠绕组式磁悬浮永磁直流平面电机PID控制系统研究

提出了一种层叠绕组式五自由度磁悬浮永磁直流平面电机的构想,针对该磁悬浮平面电机中的磁悬浮系统进行了控制系统设计。在对悬浮系统三维有限元分析的基础上利用参数辨识法构建了磁悬浮系统非线性模型;并利用微分几何方法,对磁悬浮模型进行完全精确反馈线性化,设计了PID控制器,并进行了样机控制实验。磁悬浮永磁直流平面电机悬浮高度的控制仿真和实验结果吻合度良好,系统稳态误差在1μm以内并具有优良的跟踪性能。     

进给机构磁悬浮系统的解耦控制分析

进给机构的磁悬浮系统由于结构的特点在进给运动中存在着水平y方向及垂直z方向的磁力和位移耦合现象．为此,分析推导了该磁悬浮系统的动力学方程,建立了相应的磁悬浮控制系统的状态方程．理论分析计算及仿真结果表明：通过采用状态反馈结合输入变换,可以使原来包含着变量间耦合的复杂控制系统实现解耦控制,简化了磁悬浮系统的控制过程,有利于提高进给机构运动的平稳性和定位精度．     

混合磁悬浮球系统变参数PID控制仿真

根据奇异摄动法,建立了混合磁悬浮系统非线性动态数学模型,并根据控制器参数的整定原则,提出了混合磁悬浮球的一种变参数PID控制方案．在MATLAB的Simulink环境下用S- Function编写参数变化规则模块,所进行的动态仿真结果表明,变参数PID控制器无论在上升时间、超调量,还是调节时间上都明显优于传统的PID控制器．     

Control of magnetic levitation positioning stage with an eddy current damper

To enhance the system damping,a permanent magnet set which served as an eddy current damper was added to the magnetic levitation positioning stage which consists of a moving table,four Halbach permanent magnetic arrays,four stators and displacement sensors.The dynamics model of this stage was a complex nonlinear,strong coupling system which made the control strategy to be a focus research.The nonlinear controller of the system was proposed based on the theory of differential geometry.Both simulation and experimental results show that either the decoupling control of the movement can be realized in horizontal and vertical directions,and the control performance was improved by the damper,verifying the validity and efficiency of this method.     

直线电机悬浮平台的L2鲁棒控制

永磁直线同步电机（PMLSM）悬浮平台系统的水平推力和法向力之间存在非线性耦合,且易受负载扰动和参数变化等不确定性因素的影响.为了解决上述问题并实现准确定位,在系统非线性数学模型的基础上,对水平轴和竖直轴均设计了PD位置控制器与L₂速度控制器,将解耦与扰动抑制转化为L₂速度控制器的设计问题.仿真结果表明,该方法设计的系统实现了水平方向和竖直方向的直接动态解耦,并且对负载扰动和参数变化具有很好的鲁棒性.     

STATCOM影响高压直流输电动态响应性能的仿真研究

在同步旋转坐标系下采用STATCOM(Static Synchronous Compensator)的暂态数学模型,基于非线性反馈线性化的逆系统方法,构造出STATCOM的伪线性系统,依据滑模变结构控制理论设计出STATCOM的滑模变结构控制器。在交直流系统中,SVC、STATCOM等不同的无功补偿装置对HVDC系统故障时动态响应性能的影响不同,通过对SVC,常规PI控制的STATCOM与变结构控制的STATCOM进行比较,仿真结果表明后者能更好地提高HVDC系统在故障时的动静态性能。     

基于三步法的磁悬浮球系统控制研究

针对磁悬浮球系统存在的非线性、不确定性和和外界干扰问题,为使系统输出在跟踪期望位置轨迹变化时具有良好的动态品质,设计了三步非线性控制器。该控制器由类稳态控制、可变参考前馈控制和误差反馈控制组成,按固定顺序分步骤推导完成。三步非线性控制器推导过程简单明确,所获得的控制律结构层次清晰,并且避免了高阶非线性带来的多次微分问题。仿真实验结果表明,三步非线性控制器的跟踪速度快,超调量小,跟踪效果好,不存在抖振现象。     

基于滑模状态观测器的两自由度磁悬浮球控制

首先分析了磁悬浮球绕组磁力线扭曲特性,构建了含轴向和水平两自由度的磁悬浮球运动模型,采用模型转换,将系统中的匹配性和非匹配性干扰统一重构为匹配性干扰,建立新的系统状态空间方程;其次,针对悬浮气隙中气隙速度与加速度难以获取、干扰实时性观测困难的问题,提出了含干扰重构的气隙速度、加速度滑模观测器,并基于此观测器设计了滑模跟踪控制器;最后搭建含干扰重构的滑模状态观测和跟踪协同控制仿真平台,结果表明所提控制策略在动态响应速度、跟踪误差和抗干扰能力性能方面优于传统PID控制.     

中低速磁浮列车过轨缝的间隙信号处理算法及实现

悬浮传感器间隙信号的正确处理是实现磁浮列车稳定悬浮控制的重要基础,若磁浮列车在过轨缝时的间隙信号处理不当会带来阶跃干扰,易使悬浮控制出现过度调节,影响悬浮系统的稳定性,甚至导致磁浮列车发生振动或砸轨。现实中磁浮列车也确实易在过轨缝时发生振动或砸轨现象,因此,为解决这一实际问题,结合实验线和某磁浮运行线磁浮列车过轨缝的间隙信号数据特点,提出一种新的磁浮列车过轨缝的间隙信号处理算法。该算法通过提取磁浮列车过轨缝时的实验和运行数据的间隙信号特点,区分开理想轨缝和轨道台阶,并设计了一种间隙补偿方法。仿真结果表明,所提算法可有效处理轨道台阶带来的信号干扰,提升悬浮控制系统的稳定性。     

基于场路耦合的磁悬浮永磁直线电动机控制系统

为了解决数控机床进给系统的摩擦问题,采用一种磁悬浮永磁直线电动机来实现无摩擦进给.建立磁悬浮永磁直线电动机的电压、磁链、推力和运动的数学模型及控制系统的场路耦合仿真模型,运用Ansoft软件中的Maxwell和Simplorer对磁悬浮永磁直线电动机控制系统进行场路耦合的联合仿真,并研究磁悬浮永磁直线电动机加速、刹车与反向运行过程.仿真结果表明,该磁悬浮永磁直线电动机控制系统具有良好的跟踪和抗扰性能,为深入研究整个系统的相互耦合以及搭建实验平台提供了依据.     

超导陀螺转子的磁悬浮特性分析

超导陀螺是利用低温超导体的Mdssner效应实现转子悬浮的一种精度高、能耗少的惯性器件．为研究超导陀螺转子的磁悬浮特性,文章介绍了超导陀螺的转子超导磁悬浮结构及悬浮原理,分析了转子间隙内磁通与间隙间的关系,推导出了由8个结构完全相同的超导线圈形成的球形腔内转子的磁悬浮力及磁悬浮支承刚度的定量计算公式,指出磁悬浮力的大小与间隙内磁通量的平方成正比,与间隙量的平方成反比,磁悬浮支承刚度则与间隙内磁通量的平方成正比,但与间隙量的立方成反比．根据转子受力建立了转子的二阶无阻尼偏移模型从而为转子的偏移控制奠定了基础．文章最后对实现陀螺转子的超导支承做了探讨,对影响磁悬浮力和磁悬浮刚度的因素进行了分析并提出了相应的解决方案。     

Maglev self-excited vibration suppression with a virtual sky-hooked damper

This work addresses the problem of self-excited vibration,which degrades the stability of the levitation control,decreases the ride comfort,and restricts the construction cost of maglev system.Firstly,a minimum model containing a flexible bridge and a single levitation unit is presented.Based on the simplified model,the principle underlying the self-excited vibration is explored.After investigations about the energy transmission between the levitation system and bridge,it is concluded that the increment of modal damping can dissipate the accumulated energy by the bridge and the self-excited vibration may be avoided.To enlarge the equivalent modal damping of bridge,the sky-hooked damper is adopted.Furthermore,to avoid the hardware addition of real sky-hooked damper,considering the fact that the electromagnet itself is an excellent actuator that is capable of providing sufficiently fast and large force acting on the bridge to emulate the influence of the real sky-hooked damper,the technique of the virtual sky-hooked damper is proposed.The principle underlying the virtual sky-hooked damper by electromagnet is explored and the vertical velocity of bridge is estimated.Finally,numerical and experimental results illustrating the stability improvement of the vehicle-bridge interaction system are provided.     

Saturation influence of control voltage on maglev stationary self-excited vibration

This work addresses the saturation influence of control voltage on the occurring of self-excited vibration of maglev vehicle-bridge interaction system, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, the interaction model of vehicle-bridge system is developed. Based on the interaction model, the relationship between the control voltage and vibration frequency is solved. Then, the variation of the effective direct component and fundamental harmonic are discussed. Furthermore, from the perspective of energy transmission between the levitation system and bridge, the principle underlying the self-excited vibration is explored, and the influence on the stability is discussed. Finally, in terms of the variation of the characteristic roots, the influence is analyzed further and some conclusions are obtained. This study provides a theoretical guidance for mastering the self-excited vibration problems.     

基于巨磁阻抗效应磁场测量传感器研究

针对非晶材料巨磁阻抗效应,设计并实现了一种新型磁场测量传感器,根据非晶丝的双峰特性,分析传感器的工作原理,设计传感器的闭环负反馈结构,建立了传感器的数学模型.在此基础上,通过分析传感器的误差传递函数,提出一种比例积分控制规律,可有效地消除传感器的稳态误差,提高传感器的线性度.实验结果表明：在该控制器的作用下,传感器的线...     

椭圆轨道绳系卫星系统释放的类反步法控制

为解决椭圆轨道上绳系卫星系统的稳定和快速释放问题,在传统反步法的基础上,提出了一种类反步法的非线性控制方法.与传统反步法仅适应于严格反馈系统不同,提出的类反步法非线性控制方法不仅可以应用于非严格反馈系统,并且能够充分地利用系统的非线性模型来改善控制效果.首先,基于拉格朗日力学原理,建立了椭圆轨道上绳系卫星系统释放过程的动力学模型,并通过一种新型的量纲为1的变换对动力学模型进行化简,得到了量纲为1的卫星系统模型;其次,设计了一种类反步非线性控制方法以应对绳系卫星系统模型中的耦合特性,并采用Lyapunov函数验证了各系统状态的渐进稳定性能;最后,设计了绳系卫星系统释放过程的非线性控制和PID控制的数值仿真实验,通过对比验证了所提出的类反步法非线性控制方法的有效性.仿真结果表明,所提出的类反步法控制方案不仅可以稳定、高效地控制椭圆轨道上绳系卫星系统的释放过程;而且相对比传统的PID控制方案所取得的控制效果更优.