Selective frequency compensation for a servo system

Claim 2

A servo system having a bandwidth of a predetermined frequency range for controlling the actuators of a movable member to selected ones of a plurality of desired positions, said servo system comprising: means for generating a first signal responsive to the actual positions of the movable member; means for generating a second signal responsive to a desired position for the movable member; means for combining the first and second signals to generate an error signal; means acting in response to said error signal for actuating the movable member thereby to move said movable member in a direction towards said desired position, and feedback circuit means for enhancing said error signal only in a preseleCted frequency region within the bandwidth frequency range without affecting the error signal in all other frequency regions of the bandwidth frequency range thereby increasing the loop gain in said preselected region thus causing a greater response from said movable member actuating means to an error signal in said enhanced frequency region.

Claim 3

A servo system as defined in claim 1 wherein the feedback circuit means adapted to enhance the error signal changes the gain and phase characteristics of the error signal only in the preselected frequency range.

Claim 4

A servo system as defined in claim 1 wherein the feedback circuit adapted to enhance the error signal includes means for generating a second order transfer function and a high pass transfer function for the error signal.

Claim 5

A servo system having a bandwidth of a predetermined frequency range for controlling the actuation of a movable member having a runout characteristic to selected ones of a plurality of desired positions, said servo system comprising: means for generating a first signal responsive to the actual position of the movable member; means for generating a second signal responsive to a desired position for the movable member; means for combining the first and second signals to generate an error signal; means acting in response to said error signal for actuating the movable member thereby to move said movable member in a direction towards said desired position; and feedback circuit means for amplifying said error signal only in a preselected frequency region corresponding to said runout characteristic included within the bandwidth frequency range thereby increasing the loop gain in said preselected region thus causing a greater response from said movable member actuating means to an error signal in said amplified frequency region so that an effect of said runout characteristic of said movable member is reduced.

Claim 6

A servo system having a bandwidth of a predetermined frequency range for controlling the actuation of a movable member having a runout characteristic to selected ones of a plurality of desired positions, said servo system comprising: means for generating a first signal responsive to the actual position of the movable member; means for generating a second signal responsive to a desired position for the movable member; means for combining the first and second signals to generate an error signal; means acting in response to said error signal for actuating the movable member thereby to move said movable member in a direction towards said desired position; and feedback circuit means for amplifying said error signal only in a preselected frequency region corresponding to said runout characteristic included within the bandwidth frequency range thereby increasing the loop gain in said preselected region thus causing a greater response from said movable member actuating means to an error signal in said amplified frequency region so that an effect of said runout characteristic of said movable member is reduced.

Claim 7

A servo system as defined in claim 4 wherein said feedback circuit means adapted to enhance the error signal changes the gain and phase characteristics of the error signal only in the preselected frequency region.

Claim 8

A servo system as defined in claim 4 wherein said feedback circuit means adapted to enhance the error signal includes means for generating a second order transfer function and a high pass transfer function for the error signal.