Estimation method for unobservable settling vibration of head-positioning control in hard disk drives

To improve reliability in hard disk drives, we proposed an estimation method for unobservable settling vibration in head-positioning control systems. Our proposed method uses both observability and excitability of mechanical vibrations in settling time of a track-seeking control. To see the observability, we employed the estimation method of unobservable amplitude of oscillations caused by mechanical resonances. To see the excitability, we also employed the Shock Response Spectrum (SRS) analysis that can handle the transient characteristics of mechanical vibrations. Simulations and experiments results on the track-seeking control showed that the results of our proposed method were good approximate solutions of the unobservable settling vibrations. This means that we can estimate the risk of the unobservable settling vibrations which may lead to destruction of user data in hard disk drives by using the proposed method. As a result, we can chose the best suited solution to avoid unobservable vibrations in the head-positioning control systems.     

Discrete-time LQG/LTR design and modeling of a disk drive actuatortracking servo system

This paper presents the discrete-time LQG/LTR design of a disk drive track following servo system. The servo compensator designed through linear-quadratic Gaussian control combined with loop transfer recovery (LQG/LTR) consists of a Kalman filter for state estimation and state feedback for control. The desired tracking servo performance is first formulated through a frequency shaped return ratio of the Kalman filter and subsequently recovered at the output of the plant/compensator loop through the automatic design of a discrete-time linear quadratic (LQ) regulator. Particular attention has been given to modeling the calculation time delay and bias force estimation. The excellent robustness and performance characteristics of a continuous time LQG/LTR design are theoretically unachievable due to the extremely low sampling rate and nonminimum phase plant characteristics. However, both time and frequency domain simulations show that reasonable stability margins and performance can still be recovered. This technique nearly eliminates all the trial and error typical of a conventional pole placement design of a similar system. The direct discrete-time design can handle extremely low sampling rates associated with embedded servo systems. The technique can also be used for designing multi-rate and multi-input servo systems     

Robust tracking servo system considering force disturbance for the optical disk recording system

This paper proposes a new robust tracking servo system for the optical disk recording system with feedforward controller based on the prediction of the tracking error. In optical recording systems, the feedback servo system must suppress the influence of force disturbance and parameter variation. To overcome this problem, this paper designs the robust feedback control system by using coprime factorization and disturbance observer. The detecting signal of the optical disk recording system is only a tracking error. Hence, the feedforward controller of the proposed tracking control system is constructed based on both the "zero-phase-error tracking" control theory and the prediction of the tracking error. The experimental results point out that the proposed tracking servo system has a quick and precise tracking response and keeps the residual tracking error below its tolerance.     

A gradient-based track-following controller optimization for hard disk drive

This paper presents a gradient-based parameter optimization method to find the optimal compensator that minimizes the standard deviation (/spl sigma//sub PES/) of the position error signal (PES) in a hard disk drive servo system. By using the plant response data and the PES gradient information based on the nominal plant model, optimal digital controllers that minimized the 3/spl sigma//sub PES/ of a plant with uncertainty were selected within a pre-found robust stable region. As a result, an optimal track-following controller that minimized the standard deviation of the measured PES (/spl sigma//sub PESm/) was able to be obtained without the prior knowledge of the disturbance and noise model. Furthermore, we proved that if the measurement noise is white, an optimal controller that minimizes the 3/spl sigma//sub PESm/ also minimizes the 3/spl sigma//sub PES/. Both simulation and implementation results suggest that such a gradient-based search process is faster than nongradient optimization methods such as random neighborhood search and genetic algorithms.     

Parametric vibration for electromechanical integrated electrostatic harmonic drive

In this paper, the electromechanical coupled force between flexible ring and stator of the drive system is presented. The radial displacement of the flexible ring subjected to electric field force is obtained. A critical voltage is found beyond which the flexible ring and the stator will make contact. Considering the ring contacting with the stator as a curved beam fixed at ends, an electromechanical coupled dynamic equation of the drive system is developed. From the equation, the natural frequencies and vibrating modes of the drive system are given. The periodic variable voltage is expressed as disturbance on natural frequency of the drive system and the forced response of the drive system to voltage excitation is investigated. Using Laplace transformation, the forced frequency response of the drive system to voltage excitation is obtained as well. Changes of the forced frequency response along with drive parameters are discussed. Influences of the linear excitation caused by changing boundary angle on the system vibrations are also investigated. The response frequencies are dependent on exciting frequency and natural one. As the exciting frequency is close to the natural frequency of the drive system, the resonance occurs. The flexible ring radius, clearance between the ring and stator, etc. has obvious influences on the frequency responses of the drive system.     

High-bandwidth high-accuracy rotary microactuators for magnetichard disk drive tracking servos

Reports on the design, fabrication, and testing of an electrostatic microactuator for a magnetic hard disk drive (HDD) tracking servo. The design requirements for a microactuator are investigated. These include high Z-directional stiffness, low in-plane stiffness, high structural aspect ratio, large output force, high area efficiency, low cost, and mass batch production. An area-efficient rotary microactuator design was devised, and microactuators were successfully fabricated using innovative processing technologies. The microactuator has a structural thickness of 40 μm with a minimum gap/structure width of approximately 2 μm. Its frequency response was measured and it was determined that it can be modeled as a second-order linear system, up to the 26-kHz frequency range. Moreover, the microactuator will enable the design of a servo system that exceeds a 5-kHz servo bandwidth, which is adequate to achieve a track density of more than 25 kilotrack per inch (kTPI). The microactuator/slider assembly was also tested on a spinning disk, with its position controlled by a PID controller using the magnetic position error signal written on the disk. An accuracy of about 0.05 μm was observed when the servo controller was turned on. Continuous-time dual-stage servos were designed and simulated using the μ-synthesis technique. A sequentially designed SISO and a MIMO control design method have been shown to be capable of meeting prescribed uncertainty and performance specifications     

网络CAI软件开发及其在机械设计传动中的应用

随着科学技术的快速发展,计算机辅助教学(CAI)的应用也越来越广泛,并且已经得到教育界的高度重视.本文设计开发的CAI软件是当前计算机辅助教学发展的重要内容,而且该款软件已经在机械设计传动课程中得到了成功应用,获得了良好效果.     

Position-sensorless drive of linear pulse motor for suppressingtransient vibration

The linear pulse motor (LPM) has been widely used because of its simple structure and easy control without the use of feedback. However, degradation of the response performance occurs, resulting from the transient vibration which is inherent in the LPM. The fastest way to suppress the vibration is to close the control loop using the position feedback sensor, However, the straightforward use of such a sensor feedback leads to higher cost and complicated configuration, sacrificing the structural advantage of the LPM. Therefore, the authors propose a Kalman filter-based sensorless control for suppressing the transient vibration. In this proposed control method, the LPM mover position and speed are optimally estimated using an extended Kalman filter applied to the nonlinear state equations of excitation winding circuits. The effectiveness of this method is confirmed by experiments on a prototype LPM control system using a digital signal processor     

Robust H∞ control with multiple constraints forthe track-following system of an optical disk drive

In this paper, the authors design a tracking controller which satisfies transient response specifications and maintains tracking error within a tolerable limit for the uncertain track-following system of an optical disk drive. To this end, a robust H_∞ control problem, with regional stability constraints and sinusoidal disturbance rejection is considered. The internal model principle is used for rejecting the sinusoidal disturbance caused by eccentric rotation of the disk. The authors show that a condition satisfying the regional stability constraints can be expressed in terms of a linear matrix inequality (LMI) using the Lyapunov theory and S-procedure. Finally, a tracking controller is obtained by solving an LMI optimization problem involving two LMIs. The proposed controller design method is evaluated through an experiment     

高精度投影光刻机对准微动硅片台

介绍一种高精度的光刻机对准微动硅片台的机械结构，并对其功能和工作原理进行详细叙述。     

A novel motor drive design for incremental motion system via sliding-mode control method

This paper proposes a particular motor position control drive design via a novel sliding-mode controller. The newly designed controller is especially suitable for the motor incremental motion control which is specified by a trapezoidal velocity profile. The novel sliding-mode controller is designed in accordance with the trapezoidal velocity profile to guarantee the desired performance. A motor control system associated PC-based incremental motion controller with permanent-magnet synchronous motor is built to verify the control effect. The validity of the novel incremental motion controller with sliding-mode control method is demonstrated by simulation and experimental results.     

Optimal controller design for a matrix converter based surface mounted PMSM drive system

This paper proposes a new control algorithm for a matrix converter permanent magnet synchronous motor (PMSM) drive system. First, a new switching strategy, which applies a backpropagation neural network to adjust a pseudo DC bus voltage, is proposed to reduce the current harmonics of the permanent magnet synchronous motor. Next, a two-degree-of-freedom controller is proposed to improve the system performance. The parameters of this controller are obtained by using a frequency-domain optimization technique. The controller design algorithm can be applied in an adjustable speed control system and a position control system to obtain good transient responses and good load disturbance rejection abilities. The controller design procedures require only algebraic computation. The implementation of this kind of controller is only possible by using a high-speed digital signal processor. In this paper, all the control loops, including current-loop, speed-loop, and position-loop, are implemented by a 32-b TMS320C40 digital signal processor. The hardware, therefore, is very simple. Several experimental results are shown to validate the theoretical analysis.     

Advanced simulation model for IPM motor drive with considering phase voltage and stator inductance

This paper proposes an advanced simulation model of driving system for Interior Permanent Magnet (IPM) BrushLess Direct Current (BLDC) motors driven by 120-degree conduction method (two-phase conduction method, TPCM) that is widely used for sensorless control of BLDC motors. BLDC motors can be classified as SPM (Surface mounted Permanent Magnet) and IPM motors. Simulation model of driving system with SPM motors is simple due to the constant stator inductance regardless of the rotor position. Simulation models of SPM motor driving system have been proposed in many researches. On the other hand, simulation models for IPM driving system by graphic-based simulation tool such as Matlab/Simulink have not been proposed. Simulation study about driving system of IPMs with TPCM is complex because stator inductances of IPM vary with the rotor position, as permanent magnets are embedded in the rotor. To develop sensorless scheme or improve control performance, development of control algorithm through simulation study is essential, and the simulation model that accurately reflects the characteristic of IPM is required. Therefore, this paper presents the advanced simulation model of IPM driving system, which takes into account the unique characteristic of IPM due to the position-dependent inductances. The validity of the proposed simulation model is validated by comparison to experimental and simulation results using IPM with TPCM control scheme.     

基于ARM9和QT的步进电机驱动控制系统设计与实现

本文设计了由S3C2440微处理器和驱动芯片TA8435H控制的步进电机驱动系统,并通过Linux 下应用Qt 设计开发嵌入式控制系统人机界面的方法,通过触摸屏对步进电机转速、方向、细分模式等进行控制,最后给出了QT应用程序的移植过程,移植过程采用交叉编译,系统界面直观简洁,易于操作,极大地方便了对电机的控制,使其更好地应用于工业控制领域。     

QKD系统中相位调制器驱动电路设计

相位调制器是量子密钥分发系统中不可缺少的调制器件,其输出调制信号的脉宽影响量子比特误码率.本文提出一种利用高速高频模拟开关实现相位调制器驱动电路的设计方法,仿真结果显示驱动电路输出电压脉冲脉宽可低于10ns,并能很好地应用到量子密钥分发实验系统中,从理论及实验上对实验方案的可行性及可靠性进行了验证.     

远程输电线路振动数据监测系统软件的设计

系统通过PC监控界面可以实时远程监测到输电杆塔和输电线的振动波形,并判断杆塔振动类型,大大降低了输电线路巡线作业强度。ARM通过3G网将振动数据传送至PC机,PC机对振动数据波形还原并判断振动类型,监控界面采用VS2008开发完成。     

基于加速传感器的船舶振动检测系统设计

船舶振动是船舶与海洋结构物设计中的关键技术之一,船舶架构是一种复杂的组合弹性体,本身的振动非常复杂。不同于传统的机械式船舶振动检测设计,本系统采用嵌入式系统,运用传感器检测、实时数据处理等技术,使产品具有小型、专用、易携带、可靠性高的特点,在船舶振动检测领域有广泛的应用前景。     

Robust speed control system considering vibration suppressioncaused by angular transmission error of planetary gear

This paper proposes a new robust speed control to suppress vibration caused by angular transmission error of planetary gears. For this purpose, this paper first constructs a new numerical simulation model of angular transmission error of planetary gear, which is confirmed by experimental data from a robot arm. Next, in order to suppress the vibration caused by angular transmission error, we propose a robust speed control system based on disturbance observer and coprime factorization. Numerical simulation results show that the proposed system regulates the angular speed of motor satisfactorily, and it suppresses the vibration caused by angular transmission error