磁盘存储器最佳存取控制系统的分析与设计

磁盘存储器磁头伺服定位机构一般如图1所示。其驱动电机是直线电机,径向运动位置传感器是由伺服盘和伺服磁头以及位置信号电路构成。实际上国外在略早一点的磁盘机中位置传感器是光栅或同步感应器。国内伺服磁盘盘面图案的刻制尚未解决,因此位置传感器一     

磁盘系统中磁头定位的光学方法

本文报导了磁盘系统中磁头定位的一种新的光学方法。为了提高磁头定位的精度,研究过几种不使用伺服盘的磁头定位方法,但由于记录在同一数据面上的磁头定位信号与数据信号之间产生干扰,这些方法至今都不成功。在本文说明的新方法中,磁头能用一个光学检测的位置信号定位在磁盘盘面上,同时又不扰乱磁盘系统的运行。 本文研究了一种磁盘与磁头的独特结构。它在铝基片的阳极氧化层上着色再在其上面形成一种磁膜,从而构成描述数据磁道位置的光学图形。在Winchester型铁氧体磁头中间轨道的一个孔中埋置着三条光纤维,盘面上的光学图形由这三条光纤维读出。 用光学方法从旋转的磁盘上检测出一个稳定的位置信号,用这个信号组成一个简单的伺服回路,使磁头能够以±3μm精度定位。曾经发现潜在的精度为±0.7μm。     

硬盘驱动磁头偏置误差检测算法的研究

在硬盘装配过程中,通常需要对磁头间的磁头偏置误差进行预校准,并实施有效的补偿措施以减少磁头切换时的寻址误差,提高读写效率。然而,由于剧烈震动或不当操作等因素的影响,校准好的磁头偏置可能偏离预校准值,从而导致硬盘寻址或读写性能的下降以及伺服启动时间的延长。提出了一种在硬盘正常启动过程中快速有效的磁头偏置的检测和补偿算法,设计了与磁盘扇区绑定磁头偏置滤波方案。实验表明此方法可以快速有效地识别磁头偏置,并启动相应的校准操作,提高了硬盘在剧烈震动后的伺服性能。     

一种旨在提高磁盘驱动器道密度的光记录系统结构

在磁盘驱动器中借助光伺服技术可以大幅度提高道密度我们的方法是；采用光刻工艺，在磁盘上记录高精度有磁，无磁伺服图形，通过磁头读取伺服信息。本文设计了用于刻写伺服图形的光记录系统。该系统可以完成６３５０ＴＰＩ磁盘的刻录。     

自伺服刻写中磁头OTC性能研究

定量分析磁头在整个盘片上的磁道偏移能力对自伺服刻写中参考值的确定十分重要.本文分析影响磁头磁道偏移能力的因素,其中重点讨论弯曲角对边界擦除带的作用以及由此对磁头道偏移能力的影响.在实验部分提出一种新方法,通过这种方法可以获得磁头飞过整个磁盘表面的磁头写入宽度和读取宽度,磁头道偏移能力.实验数据表明随着弯曲度的变化边界擦除带对磁头磁道偏移能力影响较大,弯曲度还造成磁头内外径磁道偏移能力的不一致性.     

大麻Marijuana病毒的诊断、激活和解毒程序

大麻病毒(也叫Marijuana病毒,或Stone病毒)是一种恶性的操作系统型病毒,病毒感染磁盘后,篡改了磁盘原有的引导记录,并将原有的引导记录移到磁盘的其它位置上。病毒被激发后,屏幕左上角出现:Your PC is now Stoned!……LEGALISE MARIJU-AHA!,同时响铃。大麻病毒的危害取决于病毒将磁盘原来的引导记录移到磁盘的什么位置上:对软盘来说,病毒将原来的引导记录从0磁道0磁头1扇区移到0磁道1磁头3扇区,常用的1.2M的双面高密度软盘和360K的双面双密度软盘的0磁道1磁头3扇区在磁盘的目录区中,存储在这个扇区中的32个目录项就被破坏了;对硬盘来说,病毒将原来的主引导记录(分区表)从0磁道0磁头1扇区移到0磁道0磁头7扇区,病毒对硬     

无刷直流电机模糊伺服控制器设计

针对直流无刷电机(BLDC)的数学模型具有较强非线性的特点,文章基于三调节因子模糊控制算法建立了其伺服控制器.与传统伺服控制器相比,为增加控制的平滑性,在模糊伺服控制器的设计中引入了第三个调节因子.将位置误差及其变化量分别作为位置控制器的输入,当位置误差处于不同的等级时采用不同的调节因子.为了验证所设计伺服控制器的有效性,分别对BLDC系统的位置跟踪、转速以及a相电流特性进行了仿真研究.此外,通过与位置环采用普通PI控制器时的位置跟踪特性进行比较,表明所设计的模糊伺服控制器性能较好,从而为无刷电机伺服控制系统的设计、开发与调试提供了一种新途径.     

磁盘机信号模拟系统的研究

文中阐述了磁盘机的特征信号模拟系统在磁盘的开发中的作用，研究了用一种任意波形产生系统来模拟并产生磁盘机的各种特征信号（如磁头的读写信号、伺服头的读出波形等）的原理与方法。     

新的基于运动控制总线的双轴协调控制方法

减小轮廓误差是轮廓线跟踪应用中的一个重要问题.在高速加工中,除了使用高响应的单轴闭环控制方法以保证跟随误差外,还要使用协调控制方法使多轴合成的轮廓误差达到指定的要求.常见的协调控制方法如交叉耦合控制,由于自身的特点,位置环在上位置装置如CNC中实现,伺服中只实现简单的速度控制.这种控制方法加重了上位装置的计算负荷,限制伺服性能的发挥,同时没有充分利用当前主流的运动控制总线的优点.为此本文提出一种新的基于运动控制总线的双轴协调控制方法,利用运动控制总线,将单轴位置环控制下放到伺服中实现.这种结构能够减轻上位装置的计算负荷,充分发挥伺服的控制优势,不改变位置控制的稳定性.通过理论分析及实验结果,验证了这种方法的优点及可行性.本文提出的方法符合运动控制总线和伺服的技术发展趋势,为协调控制探索出一条新的途径.     

磁盘磁头园柱状浮动面研磨技术

一、前言为了保证磁盘磁头浮动性能的稳定可靠,对磁头浮动块工作面不仅光洁度要求高,     

Position error reduction in magnetic disk drives using a head gimbal assembly with radial head motion capability

Reducing the head positioning error is important to achieve higher track density in hard disk drives. In this paper, it is shown that the head off-track due to disk vibration can be reduced by using a head gimbal assembly capable of moving not only vertically to disk surface but also radially across the track. We find the optimal geometric relationship to minimize the head off-track due to disk vibration. The relationship is obtained based on precise mathematical modeling of head off-track mechanism due to disk vibration. Some examples of head gimbal assembly (HGA) with radial head motion capability, which satisfy such optimal relationship, are also proposed. It is experimentally found that the proposed optimal HGA can reduce non-repeatable run-out (NRRO) position error signal (PES) significantly. Since it reduces NRRO PES during servo track writing as well, the written-in portion of repeatable run-out PES can be also significantly reduced.     

Position error signal generation in hard disk drives based on a field programmable gate array (FPGA)

The position error signal (PES) in current hard disk drives is generated from the embedded servo data and used as the input for the track following controller. The servo pattern design and the decoding are both quite complicated in terms of the servo writing and servo detection, but they are important for the system dynamics study and track following controller design. In this paper, a novel scheme based on discrete fourier transformation (DFT) to decode the servo signal from a special magnetic servo pattern and generate the PES is proposed. In the scheme adjacent magnetic tracks with different frequencies are recorded to the disk and used as servo tracks to encode the position information. Simulation results show that the amplitudes at the two writing frequencies in the readback spectrum depend on the magnetic head position. The quadrature PES defined by the difference of the amplitudes is almost linear between the two adjacent tracks The simulation and off-line experimental results analysis agree with each other and prove the feasibility of this scheme. A real-time signal acquiring and processing system with a commercial field programmable gate array (FPGA) and ADC/DAC chips was built, and the proposed scheme was implemented in the FPGA to do the high-speed signal analysis. The magnetic head position information is extracted from the readback spectrum in the FPGA and transferred to a PC host for real-time graphic display using a labview interface. The system demonstrates an ability to generate the PES at 25 K samples per second with a resolution around 3 nm. The sampling rate can be enhanced further to 125 kHz if more servo sectors are written to the disk. This system provides a re-configurable research stage for studying the dynamic behavior of hard disk drives and for developing the control algorithm for track following.     

An iterative learning approach to compensation for the servo track writing error in high track density disk drives

The servo tracks of hard disk drives are written at the time of manufacture with the equipment of servo track writer. The disk vibrations or head fluctuations during servo track writing process give rise to servo track writing error. The servo track writing error may cause some critical errors during data writing operation. In this paper, we propose a new correction algorithm for the servo track writing error based on the iterative learning control technique. The estimate of the servo track writing error is constructed from the position error signal and updated iteratively at each disk rotation. Then, the estimate of servo track writing error is used to correct the position error signal in a feed-forward manner. Our correction algorithm is robust to system model uncertainties, computationally quite simple, and has fast convergence rate. Furthermore, we give a rigorous analysis for the convergence of our correction algorithm. In order to demonstrate the practical use of our work, we present some experimental results using a commercially available hard disk drive.     

一种抑制硬盘自伺服刻写中径向误差传播的方法

磁头和数据道的相对位置是通过分析伺服信息得到的.因此伺服信息必须在硬盘生产过程中被写入.传统的伺服信息刻写过程需要借助伺服道刻写机和净房环境,这些都会使硬盘的生产成本增加.快速增长的磁道密度也给伺服信息的刻写带来很大压力.自伺服刻写能够使用硬盘自身的组件来完成伺服信息的刻写过程,因此提高硬盘的生产效率.讨论了硬盘自伺服刻写过程和其中的关键问题,分析了自伺服刻写原理及其带来的径向误差传递现象.径向误差是由于噪音扰动、"种子"磁道的缺陷和与上一磁道的高度依存性引起的.比较了现行的两种抑制自伺服刻写中误差传播的办法,分析了它们存在的问题,然后提出了一种加权型校正信号的产生方法,并从理论上和仿真条件下证明了该方法的正确性和优越性,它能同时减少磁道绝对径向误差和相对径向误差.     

Dual-stage servo systems and vibration compensation in computer hard disk drives

This paper discusses two mechatronic innovations in magnetic hard disk drive servo systems, which may have to be deployed in the near future, in order to sustain the continuing 60% annual increase in storage density of these devices. The first is the use of high bandwidth dual-stage actuator servo systems to improve the precision and track-following capability of the read/write head positioning control system. The second is the instrumentation of disk drive suspensions with vibration sensing strain gages, in order to enhance airflow-induced suspension vibration suppression in hard disk drives.     

Evolutionary design and implementation of a hard disk drive servo control system

The ever increasing demand for higher storage capacity and smaller magnetic hard disk drives have driven the need of developing a high performance head positioning servo control system. To meet the challenge, this paper presents the design and real-time implementation of a robust two-degree-of-freedom servo system for physical 3.5-in. hard disk drive with single voice-coil-motor actuator using a multi-objective evolutionary algorithm toolbox. Besides the simplicity in controller structure, such an evolutionary servo control system is capable of meeting various performance specifications of hard disk drives in both the time and frequency domains. It is shown that the servo system optimally moves the magnetic head onto the desired track with minimal control effort, and keeps it on the track robustly against plant uncertainties or runout disturbances. Validation results of the evolutionary servo control system are compared with classical PID and RPT controllers, which show excellent closed-loop response and robustness in the face of practical perturbations in HDD.     

基于Kalman滤波的滑模控制在磁盘驱动系统中的应用

针对磁盘驱动伺服系统中存在的诸多随机干扰和随机噪声等特点,常规的PID控制在该类系统中存在滞后或超调,以及传统的滑模控制要求系统不确定因素的边界为已知等缺点,本文提出了基于Kalman滤波算法的指数趋近律滑模变结构控制方法,以指数趋近律作为到达条件设计滑模变结构控制器。该方法能够较好地处理磁盘驱动伺服系统中的不确定性问题,而且对外界干扰不敏感。在MAT-LAB环境下对该算法进行了仿真试验研究,结果表明,该方法能够很好地削弱抖振和抑制伺服系统的随机干扰。将该方法应用于磁盘驱动伺服系统可以显著地改善系统的动态特性,并能使系统的稳定性和控制精度大大提高。     

硬磁盘驱动器数字伺服控制系统的设计

根据硬磁盘驱动器磁头驱动机构的状态空间模型,运用极点配置技术和最优控制技术,分别设计了磁头定位系统在寻道模式和定道模式下的数字伺服控制器,以满足磁头定位系统寻道时间、定道精度等的性能要求,同时充分考虑了功牦限制、寻道残余振荡等影响。仿真结果表明其具有较好的控制性能。     

Piezoelectric film attached suspension for detecting disk flutter and reducing track misregistration

To increase the recording density of hard disk drives, high accuracy of head positioning is required. But disk flutter, which is airflow induced vibration, is a major contributor to head positioning error. For detecting disk flutter, we proposed a suspension to which a PVDF film sensor was attached, and built the suspension into an actual HDD. Comparing the power spectrum of disk vertical vibration with that of the PVDF film sensor output, disk flutter was well detected. We also implemented a feedforward controller and confirmed that the influence of disk flutter on position error signal is considerably suppressed.