IEEE/ASME Transactions on Mechatronics

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 m... View full abstract»

We propose a new integrated head/actuator/slider concept for hard disk drives. This slider is batch fabricated on the sacrificial layer of a wafer together with an electrostatic microactuator via micromachining technology. We present the basic integrated head/actuator/slider design, the fabrication and flying-height tests of a micromachined slider body, and the design, fabrication, and testing of ... View full abstract»

A dual-stage servo system which utilizes a high-bandwidth secondary actuator has been proposed for magnetic hard disk drives. Microfabricated actuators are promising candidates for this secondary actuator, since they offer the benefits of extremely small size and weight and may be batch fabricated for reduced production cost. This paper presents the design of an electrostatic microactuator which p... View full abstract»

This paper describes a servo demodulator which provides greatly improved performance over the currently used servo demodulation methods for disk drives. The demodulation algorithm proposed here makes better use of knowledge about the readback signal coming from the disk to provide better noise immunity and more immunity to other nonidealities in the magnetic head response. The net result is a demo... View full abstract»

This paper considers a pivot friction compensator using the combination of an accelerometer and a disturbance observer. Noting that the pivot torque bias due to uncertain disturbances and nonlinearities such as pivot friction is approximately the difference between the scaled voice-coil motor (VCM) current and the scaled carriage angular acceleration, a disturbance observer to estimate the bias ca... View full abstract»

The mode switching control (MSC) is a kind of variable-structure control system with switching in only one direction. When the mode is switched from the fast-movement servo mode to the precise-positioning servo mode, the switching time is the initial time when the precise-positioning mode begins. As a result, initial value compensation (IVC), a method that takes into account the initial state valu... View full abstract»

Experimental techniques are proposed to evaluate the dynamic properties of suspension-slider-air-bearing systems. The bump responses of the sliders and gimbal structures are measured. The modal parameters, such as frequencies, damping ratios, and mode shapes of the systems are obtained by using the proposed procedure. The techniques are applied to investigate the dynamic properties of three system... View full abstract»

This paper investigates the use of photoresistive light sensor arrays as a possible lateral position sensing system for a vehicle, or several vehicles, following a lead vehicle under separate control. A brief motivation for the use of such a sensing array is followed by a derivation of an appropriate sensor layout. It is shown that the sensing array has several benefits, including cost, simplicity... View full abstract»

A novel active prediction, planning, and execution (APPE) system is presented for the robotic interception of moving objects. An APPE system's objective is simply to move the robot to the earliest pregrasping location. A fine-motion tracking algorithm can take over the motion control at that point, utilizing proximity sensors mounted on the robot's end-effector. This approach eliminates the necess... View full abstract»

Motivated by the Udwadia and Kalaba equation, it is suggested that one can take the advantage of the second-order form of constraint in a more global sense. The second-order form is especially useful in deriving equations of motion that are uncoupled and Lagrangian multiplier free. As a demonstration, the procedure of incorporating the second-order form into the Maggi's equation and Lagrange's equ... View full abstract»

A new pole-zero cancellation technique using a modified series approximation is proposed for the feedforward controller. The gain of the system with the proposed feedforward controller is close to 1 for up to relatively high frequency. The tracking error of this method depends on the pth-order difference of the desired trajectory. The method is effective when the closed-loop system has unstable ze... View full abstract»