| 摘要 |
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. A very general class of waveforms is the prototype acceleration of investigation, which includes the known waveforms of prior art as its special cases, including the classical bang-bang control, simple sinusoidal seek, more sophisticated generalized Fourier seek trajectory or even the very versatile trajectories such as extended sinusoidal waveform and the generalized sinusoidal waveform. The method of generating seeks trajectories based on a general, normalized waveform is devised. The method is universally applicable for a general waveform, which has symmetry property about its midpoint. The generation of seek states at real time is generally a tedious task. One method for the sinusoidal seek method uses recursive approach to update seek states with the use of trigonometric identities. The extension of this recursive method applies to the generalized Fourier seek trajectory. Following the same lines of recursive method with use of trigonometric identities, more tedious recursive methods can be used for either the extended sinusoidal waveform or the generalized sinusoidal waveform. However, it is much simpler and effectively to use a multi-linear approximation for any seek trajectory to generate seek states for controller. The benefit of the multi-linear approximation over the recursive method becomes even more pronounced when the waveform gets more complicated.
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