摘要:
Disclosed is a disk drive to characterize misaligned servo wedges. A disk of the disk drive includes a plurality of circumferential tracks, in which, each track includes a plurality of servo wedges spaced sequentially around the circumference of the track wherein the servo wedges may be misaligned relative to the head of the disk drive that moves about a pivot. A servo controller is used to characterize the misaligned servo wedges relative to the head during a seek operation by implementing the following operations: commanding the head to perform a seek operation from a starting track to an ending track; obtaining samples of wedge-to-wedge time (WTWT) values corresponding to time intervals between identified servo wedges for sampled tracks traversed during the seek operation; calculating WTWT variations for each sample; and calculating a calibrated misalignment value for each sample based upon WTWT variations.
摘要:
A disk drive is disclosed that estimates a sinusoidal error in a wedge time period due to eccentricity in the disk rotating to generate eccentricity compensation values. During a write operation a head is positioned over a target data sector within a target track, a write clock frequency is set using an eccentricity compensation value corresponding to the target data sector, and data is written to the target data sector using the write clock frequency. In this manner, the eccentricity compensation value adjusts the write clock frequency to better optimize the linear bit density from the inner to outer diameter tracks.
摘要:
A disk drive is disclosed comprising control circuitry for generating a control signal applied to a VCM in response to a position error signal (PES) generated from reading embedded servo sectors and a feed-forward compensation value that compensates for a repeatable runout (RRO) disturbance. The feed-forward compensation value is generated for each servo sector in response to an RRO estimate Ŝ computed recursively for each servo sector according to: S ^ n + 1 = S ^ n - λ [ S ^ n - 1 n ∑ i = 1 n PES i ] wherein: λ is a predetermined fraction; PESi is the position error signal generated for a selected servo sector during an ith revolution of the disk; and n represents a number of disk revolutions.
摘要:
A method is disclosed for adaptive learning of fundamental-frequency repeatable runout (1FRRO) compensation information in a disk drive. The disk drive includes a transducer head, a magnetic disk having a plurality of concentric data tracks defined by embedded servo wedges that provide position information, and a control system. In the method, 1FRRO compensation information is learned over a predetermined minimum number of disk revolutions. After the predetermined minimum number of disk revolutions, the 1FRRO compensation information is monitored for convergence while learning of the 1FRRO compensation information continues. Learning is terminated upon detection of convergence of the 1FRRO compensation information.
摘要:
A disk drive and method for estimating a sinusoidal error in a wedge time period is disclosed. An estimated WTP is calculated according to: EST_WTP=RTP+â*cos(2πk/N)+{circumflex over (b)}*sin(2πk/N) wherein RTP is a reference time period corresponding to a nominal WTP, k is an index representing a servo wedge, and {â,{circumflex over (b)}} are adjustable coefficients. A wedge time error e(k) is estimated as the difference between the estimated WTP and a detected actual WTP. The coefficients {â,{circumflex over (b)}} for generating the estimated WTP are adjusted according to: â(k+1)=â(k)−G*e(k)*cos(2πk/N) {circumflex over (b)}(k+1)={circumflex over (b)}(k)−G*e(k)*sin(2πk/N) wherein G is a predetermined gain.
摘要:
Disclosed is a disk drive and method to characterize misaligned servo wedges. The disk drive includes an actuator arm, a head, a disk, and a servo controller. The head is connected to a distal end of the actuator arm in which the actuator arm is rotatable about a pivot to move the head radially over the disk. The servo controller is used to characterize misaligned servo wedges by implementing operations including: commanding the head to track follow on a track; measuring wedge-to-wedge time (WTWT) values corresponding to time intervals between identified servo wedges; calculating wedge-to-wedge time (WTWT) variations for the measured WTWT values; and characterizing the calculated WTWT variations, wherein, characterizing the calculated WTWT variations for the track includes utilizing a WTWT variation modeling function to model the WTWT variations.
摘要:
A disk drive is disclosed wherein a BEMF speed error is measured during a BEMF spindle speed control mode, and a spindle control current is updated in response to the BEMF speed error to drive the disk at an operating speed. A reference time period (RTP) is calibrated, and a sinusoidal error in a wedge time period (WTP) due to eccentricity in the disk rotating is estimated to generate an eccentricity compensation value. After switching to a wedge spindle speed control mode, an actual WTP is detected and a wedge speed error is generated in response to the RTP, the detected actual WTP, and the eccentricity compensation value. The disk is then maintained at the operating speed by updating the spindle control current in response to the wedge speed error.
摘要:
A method for improving the performance of a rotary actuator in a disk drive, the rotary actuator comprises a voice coil motor (VCM) characterized by a torque parameter, the disk drive comprises a servo control system having a motor driver circuit for receiving a series of command effort signals (CEFs) transmitted based on a first seek profile, and for providing an operating current to VCM based on the CEFs for causing a movement of the actuator from a first radial location to a target radial location. The method includes recording the transmitted CEFs, and while actuator is moving: adjusting each recorded CEF to account for a disk drive influence on actuator movement; storing adjusted CEFs; monitoring velocity of moving actuator; calculating an acceleration value corresponding to moving actuator from the stored CEFs and monitored velocity; and adjusting the acceleration value to account for a radial torque parameter variation.
摘要:
A refillable dispenser for viscous compositions comprises a bottle having walls defining an upper cavity and a lower cavity, a viscous composition refill mechanism configured to allow viscous composition to enter the upper cavity when the refill mechanism is fluidly coupled to a viscous composition source and a viscous composition dispensing mechanism configured to allow viscous composition to be dispensed from the upper cavity to outside the bottle when the dispensing mechanism is actuated. A gasket configured to substantially seal the upper cavity from the lower cavity is provided wherein the gasket is capable of moving towards the upper cavity upon actuation of the dispensing mechanism and moving towards the lower cavity upon entrance of the viscous composition into the upper cavity.
摘要:
A method for providing firewall for terminals in the IMS network and a firewall system are provided. The method includes: arranging a firewall system in the IMS network; acquiring an identification information of said terminal, when the firewall system receives a request for providing the terminal with a firewall from a network element; sending an identification information of the firewall system to the terminal and related network elements; and managing at least part of the communication activities between said terminal and other network elements by the firewall system, wherein, said other network elements include network elements in the IMS network and/or network elements which communicate with said terminal via the IMS network.