模糊-PID控制器在静电悬浮转子微陀螺起支控制中的应用

针对起支控制的非线性特性,提出了模糊-PID控制器。当转子远离平衡位置时,采用模糊控制提高快速响应特性,在平衡位置附近采用PID控制器以消除系统的稳态误差。实验结果表明,采用模糊-PID控制,超调量从27%减小到20%,调节时间为25ms,显示了良好的动态性能和全局稳定性。     

静电陀螺漂移模型辨识

一、引言静电陀螺是近代高精度惯性器件,它利用静电场将一个球形转子悬浮在超高真空球腔内。由于其结构简单,转子启动后不和任何物质接触,所以其漂移率十分稳定,这样就可通过补偿,提高陀螺的极限准确度。同二自由度液浮陀螺一样,静电陀螺的漂移模型也可用比力的二次方程来描述d(x)=D(x)_F D(x)_xf_x D(x)_yf_y D(x)_f_z D(x)_(xx)f_x~2 D(x)_(zz)f_z~2 D(x)_(xy)f_xf_y D(x)_(yz)f_yf_z D(x)_(zx)f_zf_x D(x)_R(1)d(y)=D(y)_F D(y)_xf_x D(y)_yf_y D(y)_zf_z D(y)_(yy)f_y~2 D(y)_(zz)f_z~2 D(y)_(xy)f_xf_y D(y)_(yz)f_yf_z D(y)_(zx)f_zf_x D(y)_R(2)式中,D(·)表示x 轴或y 轴漂移,D_F 为常值分量(度/小时);D_x、D_y、D_z 为正比于比力分量(度/小时/g);D_(xx)、D_(yy)、D_(zz)为正比于比力平方分量(度/小时/g~2);D_(xy)、D_(yz)、D_(zx)     

静电悬浮转子微陀螺微位移信号检测系统的设计

为实现对悬浮转子微陀螺转子五自由度的测量,提出了一种频分复用的微位移检测原理,主要介绍了多频率信号发生器,前置放大器,锁相放大器组成的测试系统,设计了一种基于DDS技术的多频率信号发生器和基于锁相放大原理的解调电路。实验和分析结果表明,该电路能实现多自由度微位移检测,设计的多频率信号发生器的频率分辨率能达到0．005821Hz,相位分辨率可以达到0．006rad,检测轴向灵敏度为1．34V／μm,检测径向灵敏度为0．092V／μm,测量电路的轴向位移分辨率为0．45nm,径向位移分辨率为6．6nm,转角的分辨率为0．25μrad,位移检测电路的分辨率,灵敏度和测量范围能够满足静电悬浮转子微陀螺的控制需要。     

悬浮转子式微陀螺的反电动势转速检测

根据液浮转子式微陀螺闭环驱动系统对转子转速测量的需求,提出了一种适用于悬浮转子式微陀螺的反电动势转速检测方法.根据楞次定律,永磁转子在附有检测线圈的定子中转动时,会切割磁感线感应出反电动势.对反电动势信号进行分析,即可测得转子的转速.由于检测线圈与驱动线圈共用定子铁芯,这种检测方法在降低定于结构复杂度的同时,也引入了矩形波驱动信号带来的毛刺干扰.干扰信号经过模拟低通滤波器衰减后,通过模数转换器转换为数字信号.该信号通过单片机上运行的过零检测算法处理后,即可得到当前转子的转速.测试结果表明,该转速检测系统在刷新率为4 Hz、转速达到5 000 r/min以上时,测量值的相对误差在0.3％以内,其非线性误差为0.41％,能够满足对悬浮转子式微陀螺转速进行检测的要求.     

静电陀螺的热设计及试验研究

本文运用集中化结构建模思想,将静电陀螺的温度模型简化为一个线性定常多变量系统。并应用未知系统控制理沦,提出一种仅利用原系统阶跃响应的过渡过程时间及其稳态值设计控制器的新方法。     

有源静电悬浮系统的变预载控制

在基于静电悬浮轴承的惯性仪表中,为了保证系统的承载能力,需要选取很高的预载电压;而为了提高惯性仪表的精度,希望选取较低的预载电压以减小电场干扰力矩。为解决此问题提出了一种固定低预载与连续变预载相结合的控制方案,通过将被控对象精确反馈线性化和增益补偿后,能够保证系统性能基本不受预载电压变化的影响。实验表明,系统的预载电压降低了56.7%,高压放大器的功耗降低了45.3%。     

有源静电轴承的动刚度特性研究

针对补偿负刚度后的静电轴承一转子系统模型,讨论了PID控制参数与动刚度特性的关系,为根据刚度指标确定控制参数提供了理论依据。对三自由度静电球轴承的动刚度分析与实验结果表明,系统在低频与高频段具有较高的支承刚度,而中频刚度较低,刚度幅频特性曲线呈“浴盆”状。在系统通频带内,动态刚度主要由控制器参数决定,而高频刚度主要取决于转子的惯性项。在系统稳定区域,改变控制器参数可以灵活设定系统的动刚度特性。     

基于高速视觉的静电悬浮控制系统

静电悬浮是一种无接触式研究材料深过冷等特性的重要方法之一,为此设计了一套地面静电悬浮控制系统。基于双GPU建立图像采集和位置解算系统,使用实时检测算法完成对目标的实时检测。对样品带电以及动力学建模,通过开环-赋初值PID的控制策略,实现材料的融化悬浮等实验,省去了深紫外灯进行电荷补充的装置。实验证明,图像处理速度在304×304像素达到了700frame/s,同时规则球体控制精度约在±0.02mm以内。模型仿真控制结果和实际实验控制结果的相关参数基本一致。加入900V(该电压引起材料的加速度约为1.274m/s2)的人工扰动下,静电悬浮约340ms即可稳定,证明了基于高速视觉的静电悬浮控制系统的可行性与可靠性和静电悬浮动力学建模的准确性。     

磁悬浮与光电反馈式静电悬浮

对磁悬浮技术作简要综述,着重介绍超导磁悬浮技术的基本原理及发展现状。提出一种新的悬浮技术——静电悬浮技术,讨论静电悬浮的原理及其光电反馈控制系统,展望静电悬浮技术的应用前景。     

静电悬浮加速度计检测线路设计及实验研究

本文首先介绍静电悬浮加速度计在国内外的发展现状以及在空间技术中的应用，然后介绍静电悬浮加速度计的基本工作原理。针对测量微弱差动电容△C的检测线路进行设计，建立了用于调制△C的变压器电流电桥的等效电路模型，导出了用于调制信号放大的宽带放大电路的放大倍数KAC，分析了采用2路TTL同步方波信号控制4路单刀单掷模拟开关的解调电路工作过程，估算了滤波电路的截止频率f-3dB，使得解调信号在工作频带fs内基本保持0dB增益，在高于载波频率f0上获得较大的衰减。实验结果表明，该检测线路实际灵敏度为0．601mV／fF，考虑线路固有噪声和寄生电容的影响，最小分辨率达到1．06fF。     

基于智能运动控制器的开放式多轴联动数控系统

提出了一种以工控机为支撑平台,利用智能运动控制器对多轴联动进行位控的开放式闭环数控系统。介绍了该系统的功能,硬件和软件设计方法。实践证明,基于智能运动控制器的数控系统完全可以实现较高精度的实时控制,而且具有开放性,可实现对多轴联动的开环和闭环控制。     

Statics of levitated vehicle model with hybrid magnets

By studying the special characteristics of permanent and electronic magnets, a levitated vehicle model with hybrid magnets is established. The mathematical model of the vehicle is built based on its dynamics equation by studying its machine structure and working principle. Based on the model, the basic characteristics and the effect between the excluding forces from permanent magnets in three different spatial directions are analyzed, statics characteristics of the interference forces in three different spatial directions are studied, and self-adjusting equilibrium characteristics and stabilization are analyzed. Based on the structure above, the vehicle can levitate steadily by control system adjustment.     

3700造纸机液压系统及计算机闭环控制的应用

阐述了3700造纸机液压系统的工作原理，系统特点以及计算机闭环控制在该系统中的应用。     

闭环点位置对静电悬浮加速度计性能影响研究

为研究差动电容式静电悬浮加速度计非线性、零偏、标度因数、噪声以及量程与闭环点位置的关系,推导了闭环点位置与上述参数关系的数学模型,分析了闭环点偏移来源。通过仿真和实验对比了闭环点调节前后系统非线性、零偏和量程,通过实验研究了闭环点位置波动对系统噪声的影响。仿真和实验结果表明,将敏感质量闭环点位置调节在机械零点附近可以降低系统非线性、零偏和系统噪声,并能提高理论量程。     

Collision prevention of eccentric proof mass applied for micro-gyroscope

An innovative 3-phase AC (Alternative Current) drive circuit for the seismic disc in micro-gyroscopes is designed and verified by computer simulations and experiments. The in-plane dynamic model of the seismic disc with mass eccentricity and air gap against the centre bearing and the mathematic expression of two sinusoidal magnetic fields are developed respectively. In order to prevent the seismic disc from collision with the centre bearing and the EM (Electromagnetic) poles, an anti-collision controller is established by employing two Look-up tables which define the intensity of the applied current to the EM poles. Self-sensing technique is included to measure the real-time offset and angular position deviation (i.e., precession) of the disc by two orthogonal pairs of EM poles, without any additional sensors. The drive circuit under SPWM (Sinusoidal Pulse Width Modulation) operation and the anti-collision strategy are verified by intensive computer simulations via commercial software, OrCAD 9, and experiments.     

空压机用直流无刷电机的开环控制研究

为提高空压机整机效率,空压机采用直流无刷电机直联驱动。同时为降低成本,借鉴直接转矩控制的思想,提出了一种简单的基于单片机的变占空比开环控制方法。给出了基于Simulink的仿真计算。计算结果表明,这种控制方法简单可行,压缩机转速波动较小,且有着较好的稳定性和抗干扰能力。该方法适用于阻力矩波动较大且成本控制严格的场合,如往复式空压机和往复泵等。     

Suppression of dynamic offset of electromagnetic drive module for micro-gyroscope

An innovative 3-phase alternative current (AC) drive circuit for the seismic disc in micro-gyroscopes is designed and verified by computer simulations and experiments. The in-plane dynamic model of the seismic disc with mass eccentricity and air gap against the centre bearing and the mathematic expression of two sinusoidal magnetic fields are developed respectively. In order to prevent the seismic disc from collision with the centre bearing and the electromagnetic (EM) poles, an anti-collision controller is established by employing two look-up tables which define the intensity of the applied current to the EM poles. Self-sensing technique is included to measure the real-time offset of the disc by two orthogonal pairs of EM poles, without any additional sensors. The drive circuit under sinusoidal pulse width modulation (SPWM) operation and the anti-collision strategy are verified by intensive computer simulations via commercial software, OrCAD 9, and experiments.     

Analytical closed form model for static pull-in analysis in electrostatically actuated torsional micromirrors

The objective of this work is to create an analytical framework to study the static pull-in and also equilibrium behavior in electrostatically actuated torsional micromirrors. First the equation governing the static behavior of electrostatic torsion micromirrors is derived and normalized. Perturbation method, the method of straight forward expansion is utilized to find the pull-in angle of the mirror. Comparison of the presented results with numerical ones available in the literature shows that the proposed second order perturbation expansion gives very precise approximations for the pull-in angle of the mirror. Then straightforward perturbation expansion method is used again to analytically simulate the voltage dependent behavior in electrostatic torsion micromirrors. The results are compared with numerical and experimental findings and excellent agreement is observed.