基于H_∞理论的薄钢板磁浮控制研究

为了提高钢板无接触传输磁悬浮系统的鲁棒性和品质指标 ,本文引入H∞ 控制。首先分析了由气隙、悬浮体质量和电磁系统特性参数变化的误差模型 ,在此基础上 ,提出H∞ 控制器的设计方法。将H∞ 控制与传统PID控制进行了比较研究。

一类非线性磁浮控制系统局部分叉特性研究

理论分析表明：由于非线性磁力的作用，此类系统将产生一次余维二分叉和二次Ｈｏｐｆ分叉及异宿分叉；此时控制器参数的设计值将直接影响系统的稳定性．文中给出了分叉参数条件、分叉曲线、全开折平面相图．最后，对实际磁轴承系统进行仿真，其结果证明了理论分析的正确性．文中的分析研究为此类控制系统的优化设计、稳定控制提供了理论依据．

基于MATLAB语言磁浮控制系统仿真

给出了磁浮系统在MATLAB(SIMLINK)环境下的结构模型 ,并用S函数和定点运算工具箱实现变参数PID单片机控制的仿真。

基于改进自抗扰的永磁电磁混合悬浮型磁浮球控制方法

永磁电磁混合悬浮(PEMS)系统在降低能耗和增大悬浮气隙方面优势明显,但其非线性特征和控制难度也相对增加。针对PEMS系统中未知干扰和输入信号噪声引起的控制性能下降问题,提出一种基于改进型Levent微分器(ILevent)的自抗扰控制(ADRC)方法。首先,结合电磁悬浮(EMS)型磁浮球系统的控制结构,搭建PEMS型磁浮球控制系统试验台,并对PEMS型磁浮球系统进行动力学建模,判断系统的稳定性和能观能控特性;其次,采用双曲正切函数对Levent微分器进行改进,降低输出信号抖振,分析改进前后Levent微分器以及ADRC中TD微分器的输出性能,充分融合Levent微分器对信号噪声的鲁棒性和ADRC对干扰的估计与补偿优势,设计了ILevent-ADRC控制器;并利用带约束因子的模拟退火-粒子群(SA-CFPSO)优化算法有效的解决了ILevent-ADRC参数多、关联性强等制约问题;最后,分别对传统ADRC、PID控制和ILevent-ADRC方法在PEMS型磁浮球控制试验台上进行对比实验,验证所提方法的有效性和优越性。实验结果表明:相比于传统ADRC和PID控制方法,所提ILevent-ADRC方法有效提升了PEMS型磁浮球系统的控制性能,不仅能够有效地抑制测量信号噪声对系统的影响,而且还对系统悬浮气隙大范围变化和运行过程中受到的未知扰动具有更强的适应性和鲁棒性。研究成果为磁悬浮智能控制技术的实际应用提供了理论参考,同时对于永磁电磁混合悬浮这一类复杂的非线性系统的控制,也具有较好的参考价值。

激光跟踪仪CFIII三维控制网数据采集软件研制

根据激光跟踪仪自身特点和实际工程应用需要,设计开发了一款激光跟踪仪CFIII三维控制网数据采集软件,该软件主要为高速磁浮、火箭撬滑轨测设一类具有特殊精度要求的测量工作提供外业数据采集服务。本文首先按照软件开发的一般流程进行需求分析和功能设计,并以此为基础对激光跟踪仪控制网测量等相关功能算法进行研究,然后对其中一些关键的功能算法进行阐述,再对各项子功能进行编码实现。最后,本文设计了一系列测量对比分析和仿真计算实验对软件各项功能进行可靠性验证,实验结果表明,本文研制的软件运行正常,测量结果正确、可靠。

基于MSCMG大型遥感卫星高精度姿态控制方法

针对大力矩飞轮前馈和闭环反馈补偿复杂、对精度影响敏感性大的问题,提出了基于磁浮控制力矩陀螺闭环补偿的大型遥感卫星高精度姿态控制方法。该方法采用磁悬浮力矩陀螺为控制执行机构,通过变结构反馈补偿控制律设计,建立新的运动补偿控制系统,减小相机和卫星本体耦合效应。基于磁浮力矩陀螺力矩大、反向激励扰动小、精度高的特性,将其应用于对地遥感成像相机运动补偿控制系统中,仿真结果表明,与飞轮前馈补偿相比,姿态稳定度提高了一个数量级,有效提高空间大惯量卫星姿态控制的稳定度,提升相机对地成像质量;研究结果可为甚高精度卫星姿态控制与载荷运动补偿提供参考。

基于MSCMG的复合补偿控制提高图像配准方法

针对星上相机运动干扰影响遥感卫星图像配准精度控制难题,研究基于磁浮控制力矩陀螺(magnetically suspended control moment gyros, MSCMG)的复合补偿控制提高图像配准精度的方法。以基于MSCMG作为执行机构,采用姿态反馈补偿控制方法,避免复杂的控制系统前馈补偿及其自身干扰,姿态稳定精度达到5.8×10-5(°)/s。在此基础上,提出了MSCMG姿态补偿控制与相机运动补偿算法一体化的复合补偿控制方法。仿真结果表明:采用一体化复合补偿控制,跟踪相机步进角精度由补偿前的6 μrad提高到补偿后的0.36 μrad,提高了一个数量级以上;扫描角精度由补偿前的0.6 μrad提高到补偿后的0.45 μrad;显著提高了相机光轴指向的稳定性;研究结果可为甚高精度遥感卫星高精度图像配准设计提供参考。

Coupling vibration analysis of high-speed maglev train-viaduct systems with control loop failure

The risk of failure of the control loop can occur when a high-speed maglev train runs on viaduct.Meanwhile,the failure of the levitation magnets which balances the gravity of the maglev train could cause the train collision with track.To study the dynamic response of the train and the viaduct when the levitation magnet control loop failure occurs,a high-speed maglev train-viaduct coupling model,which includes a maglev controller fitted by measured force-gap data and considers the actual structure of train and viaduct,is established.Then the accuracy and effectiveness of the established approach are validated by comparing the computed dynamic responses and frequencies with the measurement results.After that,the dynamic responses of maglev train and viaduct are discussed under normal operation and control loop failures,and the most disadvantageous combination of control loop failures is obtained.The results show that when a single control loop fails,it only has a great influence on the failed electromagnet,and the maglev response of adjacent electromagnets has no obvious change and no collision occurs.But there is a risk of rail collisions when the dual control loop fails.

Disturbance decoupled fault diagnosis for sensor fault of maglev suspension system

A disturbance decoupled fault diagnosis strategy is proposed.This disturbance decoupled fault diagnosis is both robust to disturbances and sensitive to sensor faults of magnetic levitation control system.First,a robust controller based on a novel disturbance observer is devised to improve the disturbance attenuation ability,which greatly enhances the robustness of the system.Second,a fault reconstruction technique with adaptive method is presented,along with a strict verification for guaranteeing the robustness of fault.This fault reconstruction technique provides an accurate sensor fault reconstruction.From the results of simulation and experiments conducted on the CMS-04 maglev train,the integrated strategy is robust to model uncertainties of the system and the fault reconstruction algorithm is able to reconstruct the dynamic uncertain faults.

Self-excited vibration problems of maglev vehicle-bridge interaction system

The self-excited vibration problems of maglev vehicle-bridge interaction system were addressed, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, the coupled model containing the quintessential parts was built, and the mechanism of self-excited vibration was explained in terms of energy transmission from levitation system to bridge. Then, the influences of the parameters of the widely used integral-type proportion and derivation(PD) controller and the delay of signals on the stability of the interaction system were analyzed. The result shows that the integral-type PD control is a nonoptimal approach to solve the self-excited vibration completely. Furthermore, the differential-type PD controller can guarantee the passivity of levitation system at full band. However, the differentiation of levitation gap should be filtered by a low-pass filter due to noise of gap differentiation. The analysis indicates that a well tuned low-pass filter can still keep the coupled system stable.

Research on Dynamic Model's Building of Active Magnetic Suspension Systems

An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended under the unit feedback control system designed with the primary dynamic model obtained. Online identification in frequency domain is processed to give the precise model. Comparisons show that the experimental method is much closer to the precise model than the theoretic method based on magnetic circuit law. So this experimental method is a good choice to build the primary dynamic model of AMSS.

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.

A practical robust nonlinear controller for maglev levitation system

In order to explore the precise dynamic response of the maglev train and verify the validity of proposed controller,a maglev guideway-electromagnet-air spring-cabin coupled model is developed in the first step.Based on the coupled model,the stresses of the modules are analyzed,and it is pointed out that the inherent nonlinearity,the inner coupling,misalignments between the sensors and actuators,and external disturbances are the main issues that should be considered for the maglev engineering.Furthermore,a feedback linearization controller based on the mathematical model of a maglev module is derived,in which the nonlinearity,coupling and misalignments are taken into account.Then,to attenuate the effect of external disturbances,a disturbance observer is proposed and the dynamics of the estimation error is analyzed using the input-to-state stability theory.It shows that the error is negligible under a low-frequency disturbance.However,at the high-frequency range,the error is unacceptable and the disturbances can not be compensated in time,which lead to over designed fluctuations of levitation gap,even a clash between the upper surface of electromagnet and lower surface of guideway.To solve this problem,a novel nonlinear acceleration feedback is put forward to enhancing the attenuation ability of fast varying disturbances.Finally,numerical comparisons show that the proposed controller outperforms the traditional feedback linearization controller and maintains good robustness under disturbances.

Nonlinear Control of Magnetic Bearings

In this paper, recent results controling nonlinear systems with output tracking error constmints are applied to the design of new tracking controllers for magnetic bearings. The proposed controllers can force the rotor to track a bounded and sufficiently smooth reference trajectory asymptotically and guarantee non-contactedness betweea the rotor and the stator of the magnetic beadngs. Simulation results are included to illustrate the effectiveness of the propsed controllers.

Improved One-Cycle Control Algorithm in Five-Phase Six-Leg Switching Power Amplifiers for Magnetic Suspension Bearing

For the advantages of easy realization and rapidly intelligent response,the one-cycle control was applied in five-phase six-leg switching power amplifier for magnetic bearing.This paper improves the one-cycle control considering resistance voltage drop and derives its mathematical models.The improved algorithm is compared with the former one.The simulation and experimental results show that the improved algorithm can effectively reduce the output current ripple,achieve good tracking of the given current,improve the control accuracy,and verify the effectiveness and superiority of the method.

Single neuron network PI control of high reliability linear induction motor for Maglev

The paper deals with a new model of linear induction motor (LIM) to improve the reliability of the system. Based on the normal equation circuit of LIM considering the dynamic end effect, an equivalent circuit model with compensation of large end effect is constructed when the end effect force at synchronism is of braking character. The equivalent circuit model is used for secondary-flux oriented control of LIM. Single neuron network PI unit for LIM servo-drive is also discussed. The effectiveness of mathematical model for drive control is verified by simulations.

A practical nonlinear controller for levitation system with magnetic flux feedback

This work proposes a practical nonlinear controller for the MIMO levitation system. Firstly, the mathematical model of levitation modules is developed and the advantages of the control scheme with magnetic flux feedback are analyzed when compared with the current feedback. Then, a backstepping controller with magnetic flux feedback based on the mathematical model of levitation module is developed. To obtain magnetic flux signals for full-size maglev system, a physical method with induction coils installed to winding of the electromagnet is developed. Furthermore, to avoid its hardware addition, a novel conception of virtual magnetic flux feedback is proposed. To demonstrate the feasibility of the proposed controller, the nonlinear dynamic model of full-size maglev train with quintessential details is developed. Based on the nonlinear model, the numerical comparisons and related experimental validations are carried out. Finally, results illustrating closed-loop performance are provided.

Dynamic Analysis of Micro-machined Diamagnetic Stable Permanent Magnet Levitation System

A novel micro-machined diamagnetic stable.levitation system （MDSLS） which is composed of a free permanent magnetic rotor, a ring lifting permanent magnet and two diamagnetic stabilizers was presented. The static and dynamic stable characters of MDSLS were analyzed. The coupled non-linear differential equations were used to describe six-degree-of-freedom motion of the levitated rotor, and the equivalent surface current and combined dia- magnetic image current method were utilized to model the interaction forces and torques between the lifting perma- nent magnet and rotor permanent magnet and also between the rotor permanent magnet and diamagnetic sub- strates. Because of difficulty to get analytical solution, the numerical calculation based on Runge-Kutta method was used to solve the dynamic model. The vibration frequencies were identified b~ fast Fourier transform （FFT） analysis. According to their resonance characteristics and parameters, the translational and angular dynamic stiff- ness were also calculated. The results show that the levitation of the rotor in MDSLS is stable, and the MDSLS is potential for the application in levitation inertial sensor.

Modeling and simulation of CMS04 maglev train with active controller

The application of new-designed levitation controller requires extensive validation prior to enter into commercial service. However, huge mounts of approximations and assumptions lead the theoretical analysis away from the engineering practice. The experimental methods are time-consuming and financial expensive, even unrealizable due to the lack of suitable sensors. Numerical simulations can bridge the gap between the theoretical analysis and experimental techniques. A complete overall dynamic model of maglev levitation system is derived in this work, which includes the simple-supported bridges, the calculation of electromagnetic force with more details, the stress of levitation modules and the cabin. Based on the aforementioned model, it shows that the inherent nonlinearity, inner coupling, misalignments between the sensors and actuators, and self-excited vibration are the main issues that should be considered during the design process of controller. Then, the backstepping controller based on the mathematical model of the module with reasonable simplifications is proposed, and the stability proofs are listed. To show the advantage of controller, two numerical simulation experiments are carried out. Finally, the results illustrating closed-loop performance are provided.

A Study on the Levitation Control of the Multi-degrees-of-Freedom Rotational Machine Supported by Magnetic Bearings Using Flux Feedback

This paper deals with an open-loop characteristic of a magnetically levitated system including flux feedback. In order to design a controller to obtain a good disturbance rejection and to be insensitive to parameter variations, it might be useful to employ a flux feedback loop. The air gap flux which can be sensed by a proper sensor has linear relationship with respect to the change of the current and the air gap. This linear property decreases the inherent nonlinearity of the magnetic suspension system that is caused by the coupling between the electrical actuator and the mechanical plant. Simulation results achieved from a multi-degree-of-freedom numerical model show that the flux feedback loop makes an improvement of the performance of the magnetic suspension system against the load variations.