Abstract: A hard disk drive moves a transducer across a disk surface so that the transducer has an acceleration trajectory, which is symmetric about the midpoint of the curve. A digital signal processor known as a controller is used to control the movement of a transducer. The function of a controller is to move the transducer from its present track to a target track in accordance with a servo control routine. During the seek routine the controller moves the transducer in accordance with seek trajectories derived from a design waveform. The seek trajectories are generated at real time for the controller to perform its function. The invention addresses two important features of trajectories-based seek servomechanism.

Abstract: A hard disk drive moves a transducer across a disk surface so that the transducer has an essentially generalized sinusoidal acceleration trajectory. A digital signal processor known as a controller is used to control the movement of a transducer. The function of a controller is to move the transducer from its present track to a target track in accordance with a seek routine and a servo control routine. During the seek routine the controller moves the transducer in accordance with a generalized sinusoidal current trajectory, which is devised to be a current profile for the seek control to move a transducer from one position to another position robustly and as fast as possible. To form the generalized sinusoidal trajectory, a constant acceleration phase is inserted in the middle of the acceleration phase and also a constant deceleration phase is inserted in the middle of the deceleration phase. For seeks without coast mode, the current trajectory can be divided into five phases based on seeking status.

Abstract: A hard disk drive moves a transducer (or recording head) across a disk surface so that the transducer has an essentially extended sinusoidal acceleration trajectory. The transducer may be integrated into a slider that is incorporated into a head gimbal assembly (HGA). The HGA may be mounted to an actuator arm, which can move the transducer across the disk surface. The movement of the actuator arm and the transducer may be controlled by a controller. The function of a controller is to move the transducer from its present track to a target track in accordance with a seek routine and a servo control routine. During the seek routine the controller may move the transducer in accordance with an extended sinusoidal current trajectory. The extended sine wave is devised to be current profiles for use in seeks control to move a recording head from one position to another position fast and robustly.

Abstract: A method and apparatus for moving a transducer across a disk surface in accordance with generalized Fourier seek trajectories for position, velocity, and acceleration control. The generalized Fourier acceleration trajectory includes one or more sine functions with the coefficients determined using a least-mean-square-error technique, which optimizes the selection of the trajectory. The corresponding velocity and position trajectories are derived based on the selected acceleration trajectory. The generalized Fourier seek method and apparatus provides improved performance and robustness of hard disk drive servomechanism, including shorter seek time. Additionally, the hard disk drive is more immune to external disturbances, and the acoustic noise caused by seeking is reduced. Using the generalized Fourier seek method, the duration of acceleration and deceleration modes may be equal or different.

Abstract: A method and apparatus for moving a transducer across a disk surface so that the transducer has a generalized Fourier series seek acceleration trajectory. In one embodiment, the generalized Fourier series seek acceleration trajectory includes tuned coefficients that are determined empirically. The generalized Fourier series seek trajectories provide improved performance and robustness of hard disk drive servomechanisms, resulting in shorter seek time. Additionally, the hard disk drive is more immune to external disturbances, and the acoustic noise caused by seeking is reduced. In one embodiment, the duration of acceleration and deceleration are equal. In another embodiment, the duration of acceleration and deceleration are unequal, resulting in more flexibility to decrease residual vibrations of mechanical components, and further reduction of seek time.