Seagate Technology Incorporated

Lee Ling Tan

Xiong Liu

Choon Kiat Lim

Beng Wee Quak

Kian Keong Ooi

Ming Zhong Ding

Wing Kong Chiang

Mui Chong Chai

Yang Quan Chen

Embodiments of the present invention provide for apparatus and methods for performing unload operations, including enabling read/write heads to reach a desired velocity at the ramp. Embodiments of the present invention are particularly beneficial for handheld products where low power consumption and reliability are important requirements.

Ramp unload in disc drives

A method for generating a velocity command for an actuator assembly is provided. The actuator assembly includes an actuator arm, which is to move over a plurality of surfaces. The method begins by providing a compensation torque for each of the plurality of surfaces. A position of the actuator arm is determined so that it may be mapped to one of the plurality of surfaces, which is the present surface over which the actuator arm is moving. A target velocity is then provided for the actuator arm and input to a controller, which generates a velocity command from the target velocity and a selected compensation torque, which is the compensation torque of the present surface.

Velocity control system for an actuator assembly

A method of handling resonance effects on disc drives includes the steps of monitoring a position error signal (PES) for an actuator arm of a disc drive, generating a feedforward compensation signal from the PES using a bandpass filter, and applying the compensation signal to a servo control signal. The bandpass filter has a center frequency set to a known resonance frequency. A disc drive includes an actuator assembly including an arm for carrying a head in a transducing relation with respect to a disc in response to a control signal, and a controller that monitors a PES for the arm and generates the control signal. The controller includes a servo controller that generates a servo control signal from the PES, and a feedforward compensation element which bandpass filters the PES to generate a compensation signal which is combined with the servo control signal to generate the control signal.

Method and apparatus for handling resonance effects in disc drives using active damping

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Singapore, Singapore

Lee Ling Tan