Seek trajectory adaptation in sinusoidal seek servo hard disk drives

A method for moving a transducer across a surface of a disk, comprising:

• determining a seek length between a current track and a new track for a current seek;
• determining a seek time for moving the transducer from the current track to the new track;
• adjusting the seek time, if necessary, in response to a velocity error between a calculated velocity and a design velocity for the seek length;
• and
• exciting an actuator arm that is coupled to the transducer to move the transducer across said disk surface from the current track to the new track using an acceleration trajectory based on the seek length and seek time.

A computer program product, comprising:

• a computer usable medium having computer readable program code embodied therein to move a transducer attached to an actuator arm across a surface of a disk in a hard disk drive, the computer readable program code in said computer program product comprising:
• first computer readable program code to determine a seek length between a first track and a second track for a current seek;
• second computer readable program code to determine a seek time for moving the transducer from the current track to the new track;
• third computer readable program code to adjust the seek time, if necessary, in response to an amount of voltage available to drive the actuator arm;
• and
• fourth computer readable program code to excite the actuator arm to move the transducer across said disk surface from the first track to the second track using an acceleration trajectory based on the seek length and seek time.

A method for moving a transducer across a surface of a disk, comprising:

• determining a seek length and a seek time for a current seek from a first track to a second track;
• moving the transducer across the disk surface based on the seek length and seek time;
• computing a design position of the transducer;
• determining an actual position of the transducer;
• generating a position correction value that is a function of the design position and the actual position;
• computing a design velocity of the transducer;
• determining an actual velocity of the transducer;
• generating a velocity correction value that is a function of the design velocity, the actual velocity and the position correction value;
• storing a scaling value in a memory in response to the velocity correction value, said scaling value for multiplying with the seek time to obtain a scaled seek time during a future seek of the seek length;
• computing a design acceleration of the transducer using a generalized Fourier series seek acceleration trajectory that includes one or more tuned coefficients;
• determining an actual acceleration of the transducer;
• generating a feedforward acceleration value that is a function of the actual acceleration value;
• generating an acceleration correction value that is a function of the velocity correction value, the feedforward acceleration value and the design acceleration;
• and,
• varying the movement of the transducer in response to the generation of the acceleration correction value.