Patent ID: 7660070

Claim:
A acceleration feedforward directed seek procedure for initiating and controlling the movement of an actuator controlled read/write head of a disk storage device from an initial position to a target position comprising: (a) applying time based acceleration feedforward instructions to said actuator, progressively computed at each of a plurality of successive time intervals starting at zero and on a sinusoidal trajectory, increasing to a maximum, then decreasing, passing through a minimum, and then increasing to a switchpoint whereat the acceleration of the sinusoidal trajectory equals the acceleration of the exponential trajectory, thereby resulting in making a smooth and continuous transition to an exponentially decreasing trajectory; (b) whereupon during said exponential trajectory, acceleration and velocity are each driven, by timely computed corrections to said feedforward, to reach zero when said head reaches said target position; (c) wherein said acceleration feedforward instructions are progressively computed at each of a plurality of successive time intervals using calibration data comprising a normalized velocity trajectory look-up table incorporated in controller firmware and positional feedback data from said read/write head; (d) wherein a folded-over normalized velocity trajectory table is provided to generate a velocity demand at any given head position in a phase-plane approach, said normalized velocity trajectory table being independent of actual acceleration as well as all system-specific parameters making it reusable across all platforms and systems, said table further featuring multiple zones with varying resolution, thereby insuring accurate trajectories at low velocities when transitioning to exponential arrival.