采用实心铁磁体的磁悬浮工作台的系统辨识

在超精密磁悬浮工作台中，作为衔铁被悬浮的工作台，如果可以不采用硅钢片而直接使用实心铁磁材料，则可以大大简化加工工艺，并提高工作台的刚度，但实心铁磁材料的电涡流效应对工作台性能的影响需要由实验加以确定。针对这一问题，对一个工作台采用电工纯铁的实际系统进行了研究。实验数据及系统辨识表明，由于电涡流效应，实际物理系统的特性与理论模型有明显的差异，如果不考虑这些差异，将很难获得令人满意的控制效果。另一方面，只要对系统实施辨识，并根据辨识的结果设计磁悬浮控制器，即使采用实心铁磁材料，仍可获得良好的控制性能。     

基于DSP与FPGA的主动磁悬浮轴承控制系统设计

<正>控制系统作为主动磁悬浮轴承的核心，决定了磁轴承的工作性能。本文设计了一种基于DSP与FPGA的主动磁悬浮轴承控制系统，它以DSP实现核心控制，FPGA采集数据和输出控制信号，设计了电源模块、传感器及测量模块、隔离与功率放大模块等硬件电路。同时，控制器采用了改进的线性自抗扰控制和PI双闭环策略，编写了软硬件程序。仿真与实验结果表明，该系统能在不加转速的情况下令转子稳定悬浮，转子最大偏移量不超过14.74μm，处于保护范围0.15mm以内，基本围绕中心点运动，满足设计要求。     

一种新型多定子直线型超声电机的研究

直线型超声电机具有可直接驱动、精度高、响应快、适用于真空环境等优点，但驱动力较小。为提高工作台的负载能力，该文提出并研制了一种多定子直线型超声电机。样机由两个定子和一个动子(与工作台台面相联)组成。定子是一个利用1阶纵振和2阶弯振、带双足的兰杰文振子，双足交替驱动。讨论了该电机的驱动机理，对定子的结构进行了优化设计，给出了定子、动子、工作台一体化的设计方案，并对电机的输出性能做了初步的实验研究。     

用于XLS片子步进机的磁悬浮工作台计划

用于ＸＬＳ片子步进机的磁悬浮工作台计划位于美国墨西哥州阿尔伯克基的Ｓｐｎｄｉａ国家实验室和美国马萨诸塞州Ｔｏｗｓｂｕｒｙ的ＩＳＩ公司，最近联合签订了一个为期１２个月的共同研究和开发合同，旨在建立一个具有６个自由度的磁悬浮片子工作台。此合同项目的目的在...     

一种基于SiP技术的加速度计有源磁悬浮控制电路

加速度计是以加速度的观点来测量物体运动的传感器,它通过检测质量块的惯性力来测量载体的线加速度或角加速度。文中介绍的有源磁悬浮控制电路与陀螺浮子构成磁悬浮摆式积分陀螺加速度计,该加速度计具有量程大、测量精度高等优点。受整机系统内部装配空间的限制,在电路集成化产品的设计中,采用系统集成封装(SiP)技术设计与制作有源磁悬浮控制电路,减小电路产品的底面积和高度,适应整机系统对产品的装配和使用要求。同时详细介绍了基于SiP技术的电路设计方法,对HTCC工艺的SiP结构设计进行了阐述,并简述了HTCC工艺的SiP产品达到的技术性能和应用情况。     

六维磁悬浮纳米级精密工件台的研究

设计了“H”型六维x-y工件台，利用磁悬浮技术将工件台悬浮在x、y导轨上，消除了导轨的摩擦和磨损；直线电机无接触驱动实现了工件台的粗定位；控制不同磁悬浮电磁铁的电流大小，可以实现工件台的微定位以及逐场调平调焦。计算了工件台由于重力弯曲、热膨胀等原因引起结构变形而带来的精度误差，理论上分析证明工件台在x、y方向能满足0.02μm的定位精度要求以及达到0．1μm调焦精度和3．0μrad调平精度的要求。将应用于特征尺寸0．18μm线宽激光光刻机上。     

磁悬浮球系统中光电传感器的研究与设计

主要针对磁悬浮球系统中非接触式位移检测,依据感光器件的光伏效应原理,阐述了非接触式光电传感器的研究与设计,实现了光电信号测量微位移。通过磁悬浮球实验研究表明该传感器的精度(0.01mm)和响应速度(<0.1ms)均达到预期要求,从而给出了一种方便、低成本的位移检测方法。     

磁悬浮轴承磁场均匀性测试系统的设计

介绍了一种基于霍尔传感器的磁悬浮轴承磁场均匀性测试系统的设计。该系统由信号采集、信号处理、显示电路和控制电路等组成,并通过串口实现计算机实时显示磁悬浮轴承的磁场强度并保存数据。该系统具有测试一致性好、精度高及简单等特点,能运用于磁悬浮轴承磁场的检测,提高产品的合格率。     

基于STM32的磁悬浮轴承数字控制器设计

针对传统磁悬浮轴承转子系统开环不稳定、非线性和强耦合等特性,需要对电磁力施加主动控制才能使转子稳定悬浮的缺陷,本文设计了一种基于STM32的磁悬浮轴承数字控制器方案。该控制器以ARM STM32F407ZGT6微处理器为核心,设计了电源转换、电涡流位移传感器、功率放大器控制、实时时钟以及声光报警等硬件电路;同时编写了基于国产嵌入式实时操作系统RT-Thread的多线程软件框架,实现了数据采集、PID算法等功能。实验结果表明,该数字控制器下的磁悬浮轴承转子系统可以在200ms内达到稳定悬浮状态,运行可靠、实时性好、速度快、抗干扰能力强。     

直线电机精密工作台运动控制器设计

为了提高精密工作台的轨迹跟踪精度和动态响应性能,基于辨识出的控制对象离散化模型,利用极点配置方法设计了精密工作台运动控制器的前馈环节和反馈环节,构成具有两自由度结构的精密工作台运动控制系统.通过实验,与PD＋加速度前馈的控制方式相比较,精密工作台静态定位误差提高了0.5 μm;当精密工作台以120 mm/s匀速运动时,轨迹跟踪精度提高了3 μm;定位建立时间缩短了10 ms.结果表明,采用极点配置方法设计的运动控制器具有较好的动态响应和轨迹跟踪性能.     

Closed-loop magnetic bearing and angular velocity control of a reaction sphere actuator

This article presents the first closed-loop magnetic bearing and angular velocity experimental results of a reaction sphere actuator for satellite attitude control. The proposed reaction sphere is a permanent magnet spherical actuator whose rotor is supported by magnetic bearing and can be torqued electronically about any desired axis. The spherical actuator is composed of an 8-pole permanent magnet spherical rotor and of a 20-pole stator with electromagnets. The electromechanical model of the reaction sphere is summarized together with procedures to estimate the rotor magnetic state, the back-EMF voltage, and the rotor angular velocity, which are all fundamental ingredients for controller design. Dynamic controllers are developed to levitate the rotor inside the stator (magnetic bearing) and to control the rotor angular velocity. The magnetic bearing is based on a state-space controller with reduced-order displacement velocity estimator whereas the angular velocity controller is a simple proportional controller with a dedicated angular velocity estimator. The developed control algorithms are experimentally validated using the developed laboratory prototype showing the ability of simultaneously levitating the rotor while rotating it about a given arbitrary axis.     

Ultra precision motion control of a multiple degrees of freedommagnetic suspension stage

A general framework for ultra precision motion control of magnetic suspension actuation systems with large travel ranges in multiple degrees of freedom (DOF) is presented. It encompasses the development of nonlinear electromagnetic force model for 6-DOF actuation, and the design of the necessary control architecture for ultra precision motion control of magnetic suspension actuation systems. A 6-DOF magnetic suspension stage (MSS) was designed and fabricated to illustrate the developed framework. The MSS consists of multiple electromagnets that are located around the flotor and are utilized to suspend and modulate its position and orientation. The control architecture takes the six control parameters provided by a laser measuring system and intends to control the 6-DOF motion by regulating the current in the electromagnets. The developed robust nonlinear control architecture consists of three components: 1) feedback linearization; 2) force distribution; and 3) H_∞ robust controllers for each DOF of motion. Several experiments are designed to illustrate the desired characteristics of the developed system     

A new MAGLEV system for magnetically levitated carrier system

A power-saving electromagnetic suspension system has been developed in which electromagnets with permanent magnets are used to suspend the vehicle. The electromagnets are controlled to maintain air gap length so that the attractive force by the permanent magnet always balances the total weight of the vehicle and its loads, based on modern control theory. This technology realizes a significantly power-saving system in which the electromagnetic coil current required to keep a vehicle levitating was extremely small, ideally zero. The 8-kg weight test vehicle with 4-kg load could be levitated continuously over 8 h, without recharging the on-board 1300-mAh batteries. This technology realized a completely contact-free material transportation system when combined with a contact-free driving system using linear motors. The attractive force characteristics of a permanent magnet with control electromagnets and the newly developed electromagnet control system that can eliminate power collecting devices from the electromagnetic suspension system are described     

Detail and experimental results of ferromagnetic levitation system of Japan air lines HSST-01/-02 vehicles

HSST is an acronym for high-speed surface transport and is the trade name of the vehicle levitated by the attractive electromagnets and propelled by the linear induction motor (LIM) developed by Japan Air Lines. Two test vehicles have been designed, manufactured, and flight-tested. The first test vehicle, HSST-01, marked a maximum speed of 307.8 km/h on a 1300-m long test track in February, 1978, whereas the second test vehicle, HSST-02, has demonstrated boarding test flights successfully to an aggregated total of abut 1500 passengers since April, 1978, onward. The HSST-01 weighs one ton, is 4 m long, designed for high-speed testing, and incorporates eight electromagnets and a LIM with a maximum thrust of 300 kg. The levitating power supply is taken from the batteries carried on board the vehicle, and the three-phase VVVF power for the LIM propulsion is supplied from the wayside power lines through the power collector. The nine-seated HSST-02 has a loaded weight of 2.3 tons. Major items of additional functions realized in the HSST-02 include: 1) the electromagnets are fitted to the flexible chassis for better riding comfort by incorporating mechanical suspension between the chassis and the body, and 2) with the continuous levitation, the power for the LIM is rectified and supplied to the electromagnets jointly serving with the batteries carried on board. In light of the test results obtained so far, it is shown that the predicted performances of the levitation magnets, LIM, and the power collector system have been satisfactorily established, and that there would be no major technical problems in the course of our future development for implementation of the HSST system toward commercial services. The design of a preoperational test vehicle is now underway, and its test flight is scheduled to he initiated in 1980. This 80-seated preoperational test vehicle will have test flights on a 15-km test tract at a target crusing speed of 300 km/h.     

A prototype mechanism for three-dimensional levitated movement of a small magnet

This paper deals with basic technologies for noncontact manipulation of small objects using magnets in micromachine applications. A small permanent magnet is manipulated by controlling the magnetic field applied to it. We propose a prototype mechanism to control the magnetic field for 3D levitated movement of an object. The prototype consists of eight electromagnets, pole-pieces to connect the magnetic poles, a soft iron yoke, and permanent magnets embedded in the yoke to compensate for the gravitational force of an object (a small permanent magnet). Regulation of a magnetic field and, as a result, motion of the object are strongly related to the geometric design of the pole-piece. A strategy for the pole-piece design is proposed and tested experimentally. Motion of the object in the vertical direction is realized by controlling the sum of the electromagnet currents for regulation of magnetic field gradient. Motion in the horizontal plane is realized by controlling the ratio of each electromagnet current for regulating the location of the maximum magnetic field. Results of several experiments show that the proposed prototype is effective.     

A 40-mW 55 Mb/s CMOS equalizer for use in magnetic storage readchannels

A monolithic active equalizer in 2-μm CMOS technology is described, suitable for use in magnetic storage read channels employing peak-detection. Computer simulation of the channel and numerical optimization of equalizer performance have led to a 4-pole equalizer which outperforms conventional 7-pole linear-phase pulse-slimming equalizers. Circuits with matched and scaled stray capacitances use low transconductance amplifiers, with a total on-chip power dissipation of 40 mW (excluding output buffers). A master-slave architecture tunes filter pole frequencies and quality factors (Q) to their nominal values against process and temperature variations     

Newly developed millimeter-sized superconducting linear actuatorwith superconducting slider

A millimeter-sized superconducting linear actuator has been developed. The actuator consists of a superconducting slider, a stator, amplifiers, and a personal computer. Exciting currents for six-phase excitation are applied to the electromagnets of the stator. The experimental results show that the superconducting slider moves over the stator without any mechanical contacts and that the motion resembles a stepping motor. The stable position for the levitating slider depends on the magnetic field produced by the electromagnets. The maximum speed of the slider is more than 10 mm/s     

微带发夹型谐振器滤波器的实验研究

微带发夹型谐振器滤波器具有尺寸小、成本低、易于集成等优点,在微波平面电路的设计中有着良好的应用前景.此前已有一些文献对这类滤波器进行过研究,但一般都是只针对某一种特定的发夹型谐振器进行滤波器的分析设计,而没有对各种不同谐振器的性能指标与滤波器设计要求进行比较研究.本文使用几种不同的发夹型谐振器和不同耦合方式分别设计了三阶和四阶带通滤波器,通过实验对这几种谐振器滤波器进行了分析研究,得到了一些具有实际应用价值的结论.     

Magnetically levitated micro PM motors by two types of activemagnetic bearings

This paper describes magnetically levitated micro permanent magnet (PM) motors by two types of active magnetic bearings. The micro PM motors consist of a cylindrical rotor (φ2.0 mm×10 mm), a pair of electromagnets, a pair of photodiodes, and an analog PD controller. The motors are characterized by the small rotor levitated without any mechanical contacts and one-axis controlled active magnetic bearing. Horseshoe-shaped and cylindrical electromagnets are applied to the active magnetic bearing. The rotor successfully rotates, levitating in the center of the electromagnets. In this paper, dynamic characteristics of the two types of micro PM motors, such as relationships between rotation speed and driving current, rotation speed and time, and acceleration and driving current, are discussed. As a result, it is found that the magnetically levitated micro PM motors by two types of active magnetic bearings are very different from each other and very promising     

Electronic scanning by ferrite-loaded corner reflector antennas

The measured performances of the antennas which consist of a90degcorner reflector, a horn, a core wire of a coaxial line, two or three ferrite rods, and electromagnets magnetizing the respective ferrites are presented. The following are made clear for the antenna with two ferrite rods. The load of the ferrites yields the asymmetric power pattern owing to the anisotropy of the ferrites, though the antenna geometry and the magnetization of the ferrites are symmetric. Moreover, the remarkably sharper main lobe and the higher gain are obtained by loading the ferrites. The main lobe can be turned to the direction reflected about the symmetric plane of the antenna by reversing all the dc magnetic fields applied to the ferrites, that is, electronic lobe switching in theH-plane is realized. It is shown that the antenna loaded with three ferrite rods makes the continuous scan of the main lobe possible by applying the suitable magnetic fields to the ferrites. The direction of the main lobe of these antennas is turned by electronically changing the currents of the electromagnets, that is, by changing the tensor permeabilities of the ferrites. The reciprocity for antennas composed of isotropic media does not hold for these antennas. The receiving power pattern coincides with the transmitting pattern reflected about the symmetric plane when the same dc magnetic fields are applied for both cases. Hence, these antennas permit us to receive from a direction and simultaneously to transmit in the direction reflected about the symmetric plane.