Actuating system

Claim 2

In combination, a platen having a planar configuration and having a plurality of poles disposed at spaced positions along a particular axis, first pickoff means having poles disposed relative to the poles on the platen to move along the particular axis relative to the platen and to generate a first periodic function in accordance with the movement of the poles on the first pickoff means along the particular axis relative to the poles on the platen, second pickoff means having poles disposed relative to the poles on the platen to move along the particular axis relative to the platen and disposed relative to the first pickoff means to generate a second periodic function in accordance with the movement of the poles on the second pickoff means along the particular axis relative to the poles on the platen, means responsive to the generation of the first periodic function in accordance with the movement of the first pickoff means along the first particular axis relative to the platen for generating signals representing the first periodic function, means responsive to the generation of the second periodic function in accordance with the movement of the second pickoff means along the second particular axis relative to the platen for generating signals representing the second periodic function, first actuator means having poles disposed relative to the poles on the platen to move along the particular axis relative to the platen and operatively coupled to the first and second pickoff means, the first actuator means being responsive to the signals representing the first periodic function for producing forces for driving the first and second pickoff means in accordance with the characteristics of such signals, second actuator means having poles disposed relative to the poles on the platen to move along the particular axis relative to the platen and operatively coupled to the first and second pickoff means, the second actuator means being responsive to the signals representing the second periodic function for producing forces for driving the first and second pickoff means in accordance with the characteristics of such signals, and means responsive to the signals generated by the first and second pickoff means for controlling the operation of the actuator means to prevent the pickoff means and the actuator means from rotating about an axis substantially normal to a surface including the particular axis.

Claim 3

In the combination set forth in claim 1, the poles on the first pickoff means having a particular relationship to the poles on the platen relative to the poles on the second pickoff means and the poles on the first actuator means having the particular relationship to the poles on the platen relative to the poles on the second actuator means.

Claim 4

In the combination set forth in claim 2, the poles on the first and second pickoff means being magnetic and the first and second signal-producing means respectively including windings on the poles of the first and second pickoff means, the poles of the actuator means constituting permanent magnets and the first and second actuator means respectively including windings on the poles of the actuator means.

Claim 5

In combination, a platen having a first plurality of poles disposed at spaced positions along a first particular axis and having a second plurality of poles disposed at spaced positions along a second particular axis, first pickoff means having a plurality of poles disposed relative to the first plurality of poles on the platen to sense the position of the first plurality of poles on the platen relative to the plurality of poles on the first pickoff means Along the first particular axis and to generate first periodic signals in accordance with progressive displacements between the poles on the first pickoff means and the poles on the platen along the first particular axis, second pickoff means operatively coupled to the first pickoff means for movement with the first pickoff means and having a plurality of poles disposed relative to the second plurality of poles on the platen to sense the position of the second plurality of poles on the platen relative to the plurality of poles on the second pickoff means along the second particular axis and to generate second periodic signals in accordance with progressive displacements between the poles on the second pickoff means and the poles on the platen along the second particular axis, first actuator means operatively coupled to the first and second pickoff means and having a plurality of poles disposed relative to the poles of the first pickoff means and responsive to the periodic signals generated by the first pickoff means and having characteristics of being energized to drive the first and second pickoff means along the first particular axis in accordance with such periodic signals, second actuator means operatively coupled to the second pickoff means and having a plurality of poles disposed relative to the poles of the second pickoff means and responsive to the periodic signals generated by the second pickoff means and having characterisitics of being energized to drive the first and second pickoff means along the second particular axis in accordance with such periodic signals, third pickoff means having a plurality of poles in a particular relationship to the poles on the first pickoff means and disposed relative to the first plurality of poles on the platen to sense the position of the first plurality of poles on the platen relative to the plurality of poles on the third pickoff means along the first particular axis and to generate third periodic signals in accordance with progressive displacements between the poles on the third pickoff means and the first plurality of poles on the platen along the first particular axis, third actuator means operatively coupled to the first, second and third pickoff means and having a plurality of poles disposed relative to the poles of the first pickoff means and responsive to periodic signals generated by the third pickoff means and having characteristics of being energized to drive the first, second and third pickoff means along the first particular axis in accordance with such periodic signals, means responsive to the periodic signals generated by the first and third pickoff means for combining such signals in a particular relationship to generate control signals representing any rotation of the first, second and third pickoff means and the first, second and third actuator means about an axis substantially normal to a surface including the first and second particular axes, and means responsive to the control signals generated by the last mentioned means for introducing such signals to the first and third actuator means to inhibit the rotation of the first and second pickoff means and the first and second actuator means about the axis substantially normal to the surface including the first and second particular axes.

Claim 6

In combination, a platen having a first plurality of poles disposed at spaced positions along a first particular axis and having a second plurality of poles disposed at spaced positions along a second particular axis, first pickoff means having a plurality of poles disposed relative to the first plurality of poles on the platen to sense the position of the first plurality of poles on the platen relative to the plurality of poles on the first pickoff means Along the first particular axis and to generate first periodic signals in accordance with progressive displacements between the poles on the first pickoff means and the poles on the platen along the first particular axis, second pickoff means operatively coupled to the first pickoff means for movement with the first pickoff means and having a plurality of poles disposed relative to the second plurality of poles on the platen to sense the position of the second plurality of poles on the platen relative to the plurality of poles on the second pickoff means along the second particular axis and to generate second periodic signals in accordance with progressive displacements between the poles on the second pickoff means and the poles on the platen along the second particular axis, first actuator means operatively coupled to the first and second pickoff means and having a plurality of poles disposed relative to the poles of the first pickoff means and responsive to the periodic signals generated by the first pickoff means and having characteristics of being energized to drive the first and second pickoff means along the first particular axis in accordance with such periodic signals, second actuator means operatively coupled to the second pickoff means and having a plurality of poles disposed relative to the poles of the second pickoff means and responsive to the periodic signals generated by the second pickoff means and having characterisitics of being energized to drive the first and second pickoff means along the second particular axis in accordance with such periodic signals, third pickoff means having a plurality of poles in a particular relationship to the poles on the first pickoff means and disposed relative to the first plurality of poles on the platen to sense the position of the first plurality of poles on the platen relative to the plurality of poles on the third pickoff means along the first particular axis and to generate third periodic signals in accordance with progressive displacements between the poles on the third pickoff means and the first plurality of poles on the platen along the first particular axis, third actuator means operatively coupled to the first, second and third pickoff means and having a plurality of poles disposed relative to the poles of the first pickoff means and responsive to periodic signals generated by the third pickoff means and having characteristics of being energized to drive the first, second and third pickoff means along the first particular axis in accordance with such periodic signals, means responsive to the periodic signals generated by the first and third pickoff means for combining such signals in a particular relationship to generate control signals representing any rotation of the first, second and third pickoff means and the first, second and third actuator means about an axis substantially normal to a surface including the first and second particular axes, and means responsive to the control signals generated by the last mentioned means for introducing such signals to the first and third actuator means to inhibit the rotation of the first and second pickoff means and the first and second actuator means about the axis substantially normal to the surface including the first and second particular axes.

Claim 7

The combination set forth in claim 4 wherein the platen is magnetic and the first and second pickoff means and the first and second actuator means have magnetizable properties.

Claim 8

A closed loop control system for controlling the positioning of an actuator along a particular axis on a platen constructed to provide a periodic function along the particular axis, including: first and second pickoff means disposed in a particular phase relationship to each other and to the periodic function of the platen and connected to the actuator and movable therewith and disposed relative to the platen for generating first and second periodic signals having the particular phase relationship to eacH other in accordance with the positioning of said pickoff means relative to each other and to the periodic function of said platen along said particular axis on said platen, means for providing first and second command signals having the particular phase relationship representing the desired positioning of said actuator along said particular axis on said platen, means for comparing the output of said pickoff means with said command signals to produce error signals representing differences between the desired and actual displacements of the pickoff means relative to the platen along the particular axis, said error signal means including a first multiplier responsive to the first pickoff and command signals for producing a first multiplication signal and further including a second multiplier responsive to the second pickoff and command signals for producing a second multiplication signal and further including a summer responsive to the first and second multiplication signals for producing the error signals, means including a third multiplier responsive to the error signals and the first pickoff signals for multiplying the error signals and the first signals from the first pickoff means for producing first position control signals for controlling the operation of said actuator, means including a fourth multiplier responsive to the error signals and the second pickoff signals for multiplying the error signals and the second signals from the second pickoff means for producing second position control signals for controlling the operation of said actuator, and means responsive to said first and second position control signals for driving said actuator along said particular axis relative to said platen in response to said first and second position control signals.

Claim 9

A closed loop control system for controlling the positioning of an actuator along a particular axis on a platen constructed to provide a periodic function along the particular axis, including: first and second pickoff means disposed in a particular phase relationship to each other and to the periodic function of the platen and connected to the actuator and movable therewith and disposed relative to the platen for generating first and second periodic signals having the particular phase relationship to eacH other in accordance with the positioning of said pickoff means relative to each other and to the periodic function of said platen along said particular axis on said platen, means for providing first and second command signals having the particular phase relationship representing the desired positioning of said actuator along said particular axis on said platen, means for comparing the output of said pickoff means with said command signals to produce error signals representing differences between the desired and actual displacements of the pickoff means relative to the platen along the particular axis, said error signal means including a first multiplier responsive to the first pickoff and command signals for producing a first multiplication signal and further including a second multiplier responsive to the second pickoff and command signals for producing a second multiplication signal and further including a summer responsive to the first and second multiplication signals for producing the error signals, means including a third multiplier responsive to the error signals and the first pickoff signals for multiplying the error signals and the first signals from the first pickoff means for producing first position control signals for controlling the operation of said actuator, means including a fourth multiplier responsive to the error signals and the second pickoff signals for multiplying the error signals and the second signals from the second pickoff means for producing second position control signals for controlling the operation of said actuator, and means responsive to said first and second position control signals for driving said actuator along said particular axis relative to said platen in response to said first and second position control signals.

Claim 10

The system of claim 6 wherein said platen is a magnetic grid and wherein said pickoff means comprise a pair of magnetic pickoffs having pole faces with dimensions related to the dimensions of said magnetic grid, the pole faces of said pickoffs being positioned over said platen in spaced quadrature phase relationship with each other.

Claim 11

A closed loop system including: a platen constructed to provide a periodic function along each of first and second coordinate axes, first and second actuator means having a particular phase relationship along the first coordinate axes for cooperating with the platen to provide a movement along the first particular axis relative to the platen, third and fourth actuator means having the particular phase relationship along the second coordinate axis for cooperating with the platen to provide a movement along the second particular axis relative to the platen, first and second pickoff means movable with the first and second actuator means and disposed in the particular phase relative to each other along the first coordinate axis and relative to the platen for respectively generating first and second periodic signals in accordance with the positioning of said first and second pickoff means along said first particular axis relative to the periodic function of said platen along said first particular axis, third and fourth pickoff means movable with the third and fourth actuator means and disposed in the particular phase relative to each other along the second coordinate axis and relative to the platen for respectively generating third and fourth periodic signals in accordance with the positioning of said third and fourth pickoff means along said second particular axis relative to the periodic function of said platen along said second particular axis, first command signal means for providing first and second command signals having the particular phase relationship and representing the desired positioning of said first and second actuator means and said first and second pickoff means along said first particular axis relative to said platen, second command signal means for providing third and fourth command signals representinG the desired positioning of said third and fourth actuator means and said third and fourth pickoff means along said second particular axis relative to said platen, first error signal means for comparing the signals from said first pickoff means and said first command signals and from said second pickoff means and said second command signals to produce first error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the first particular axis, the first error signal means including a first multiplier responsive to the firt pickoff and command signals for producing first multiplication signals and further including a second multiplier responsive to the second pickoff and command signals for producing second multiplication signals and further including a first summer responsive to the first and second multiplication signals for producing the first error signals, first means including a third multiplier responsive to the first error signals and the signals from the first pickoff means for multiplying the first error signals and the signals from the first pickoff means for producing first periodic position control signals for controlling the operation of the first actuator means, means for driving said first actuator means along said first axis in accordance with the characteristics of said first periodic position control signals, second means including a fourth multiplier responsive to the first error signals and the signals from the second pickoff means for multiplying the first error signals and the signals from the second pickoff means for producing second periodic position control signals for controlling the operation of said second actuator means, means for driving the second actuator means along the second axis in accordance with the characteristics of said second periodic position control signals, second error signal means for comparing the signals of said third pickoff means and said third command signals and from said fourth pickoff means and said fourth command signals to produce second error signals representing any differences between the desired and actual positioning of the third and fourth actuator means relative to the platen along the second particular axis, the second error signal means including a second multiplier responsive to the third pickoff and command signals for producing fifth multiplication signals and further including a sixth multiplier responsive to the fourth pickoff and command signals for producing sixth multiplication signals and further including a second summer responsive to the fifth and sixth multiplication signals for producing the second error signals, third means including a seventh multiplier responsive to the second error signals and the signals from the third pickoff means for combining the second error signals and the signals from the third pickoff means for producing third periodic position control signals for controlling the operation of the third actuator means, means for driving said third actuator means along said second particular axis in accordance with the characteristics of said third periodic position control signals, fourth means including an eighth multiplier responsive to the second error signals and the signals from the fourth pickoff means for combining the second error signals and the signals from the fourth pickoff means for producing fourth periodic position control signals, and means for driving said fourth actuator means along said second particular axis in accordance with the characteristics of said fourth periodic position control signals.

Claim 12

A closed loop system including: a platen constructed to provide a periodic function along each of first and second coordinate axes, first and second actuator means having a particular phase relationship along the first coordinate axes for cooperating with the platen to provide a movement along the first particular axis relative to the platen, third and fourth actuator means having the particular phase relationship along the second coordinate axis for cooperating with the platen to provide a movement along the second particular axis relative to the platen, first and second pickoff means movable with the first and second actuator means and disposed in the particular phase relative to each other along the first coordinate axis and relative to the platen for respectively generating first and second periodic signals in accordance with the positioning of said first and second pickoff means along said first particular axis relative to the periodic function of said platen along said first particular axis, third and fourth pickoff means movable with the third and fourth actuator means and disposed in the particular phase relative to each other along the second coordinate axis and relative to the platen for respectively generating third and fourth periodic signals in accordance with the positioning of said third and fourth pickoff means along said second particular axis relative to the periodic function of said platen along said second particular axis, first command signal means for providing first and second command signals having the particular phase relationship and representing the desired positioning of said first and second actuator means and said first and second pickoff means along said first particular axis relative to said platen, second command signal means for providing third and fourth command signals representinG the desired positioning of said third and fourth actuator means and said third and fourth pickoff means along said second particular axis relative to said platen, first error signal means for comparing the signals from said first pickoff means and said first command signals and from said second pickoff means and said second command signals to produce first error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the first particular axis, the first error signal means including a first multiplier responsive to the firt pickoff and command signals for producing first multiplication signals and further including a second multiplier responsive to the second pickoff and command signals for producing second multiplication signals and further including a first summer responsive to the first and second multiplication signals for producing the first error signals, first means including a third multiplier responsive to the first error signals and the signals from the first pickoff means for multiplying the first error signals and the signals from the first pickoff means for producing first periodic position control signals for controlling the operation of the first actuator means, means for driving said first actuator means along said first axis in accordance with the characteristics of said first periodic position control signals, second means including a fourth multiplier responsive to the first error signals and the signals from the second pickoff means for multiplying the first error signals and the signals from the second pickoff means for producing second periodic position control signals for controlling the operation of said second actuator means, means for driving the second actuator means along the second axis in accordance with the characteristics of said second periodic position control signals, second error signal means for comparing the signals of said third pickoff means and said third command signals and from said fourth pickoff means and said fourth command signals to produce second error signals representing any differences between the desired and actual positioning of the third and fourth actuator means relative to the platen along the second particular axis, the second error signal means including a second multiplier responsive to the third pickoff and command signals for producing fifth multiplication signals and further including a sixth multiplier responsive to the fourth pickoff and command signals for producing sixth multiplication signals and further including a second summer responsive to the fifth and sixth multiplication signals for producing the second error signals, third means including a seventh multiplier responsive to the second error signals and the signals from the third pickoff means for combining the second error signals and the signals from the third pickoff means for producing third periodic position control signals for controlling the operation of the third actuator means, means for driving said third actuator means along said second particular axis in accordance with the characteristics of said third periodic position control signals, fourth means including an eighth multiplier responsive to the second error signals and the signals from the fourth pickoff means for combining the second error signals and the signals from the fourth pickoff means for producing fourth periodic position control signals, and means for driving said fourth actuator means along said second particular axis in accordance with the characteristics of said fourth periodic position control signals.

Claim 13

The system set forth in claim 8, wherein said platen is a magnetic grid defining the periodic functions along the first and second axes and wherein said first and second pickoff means comprise a pair of magnetic pickoffs disposed along said first particular axis in the particular phase relationship and each having pole facEs in a second particular phase relationship to the pole faces of the other magnetic pickoff in the pair and wherein said third and fourth pickoff means comprise a pair of magnetic pickoffs disposed along said second particular axis in the particular phase relationship and each having pole faces in the second particular phase relationship to the pole faces of the other magnetic pickoff in the pair.

Claim 14

A closed loop system including: a platen constructed to provide a periodic function along each of first and second coordinate axes, first actuator means for providing a movement along the first particular axis relative to the platen, second actuator means for providing a movement along the second particular axis relative to the platen where the second particular axis is coordinate with the first particular axis, first pickoff means movable with the first and second actuator means and disposed relative to the platen for generating first periodic signals in accordance with the positioning of said first pickoff means along said first particular axis relative to the periodic function of said platen along said first particular axis, second pickoff means movable with the first and second actuator means and disposed relative to the platen for generating second periodic signals in accordance with the positioning of said second pickoff means along said second particular axis relative to the periodic function of said platen along said second particular axis, means for providing first command signals representing the desired positioning of said first and second actuator means and said first and second pickoff means along said first particular axis relative to said platen, means for providing second command signals representing the desired positioning of said first and second actuator means and said first and second pickoff means along said second particular axis relative to said platen, means for comparing the signals from said first pickoff means and said first command signals to produce first error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the first particular axis, first means for multiplying the first error signals and the signals from the first pickoff means for producing first periodic position control signals for controlling the operation of the first actuator means, means for driving said first actuator means along said first axis in accordance with the characteristics of said first periodic position control signals, means for comparing the output of said second pickoff means and said second command signals to produce second error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the second particular axis, second means for combining the second error signals and the signals from the second pickoff means for producing second periodic position control signals for controlling the operation of the second actuator means, means for driving said second actuator means along said second particular axis in accordance with the characteristics of said second periodic position control signals, wherein each of said first and second pickoff means includes means for generating a pair of pickoff signals having a particular phase difference and having a trigonometric function related to the positioning of said pickoff means along its particular axis relative to the platen and said means for providing command signals along each axis includes means for generating a pair of command signals having the particular phase difference and having a trigonometric function related to the desired positioning of said pickoff means along said platen, said first comparing means for generating the first error signals including means for generating a first pair of error signals having a trigonometric function and having the particular phasE difference and having characteristics in accordance with any difference between the associated pickoff and command signals in the pair, said second comparing means for generating the second error signals including means for generating a second pair of error signals having a trigonometric function and having the particular phase difference and having characteristics in accordance with any difference between the associated pickoff and command signals in the pair, said first means for producing the first position control signals including means for multiplying individual ones of the pair of pickoff signals from the first pickoff means and individual ones of the first pair of error signals to generate a first pair of position control signals having the particular phase difference, and said second means for producing the second position control signals including means for multiplying individual ones of the pair of pickoff signals from the second pickoff means and individual ones of the second pair of error signals to generate a second pair of pickoff signals.

Claim 15

A closed loop system including: a platen constructed to provide a periodic function along each of first and second coordinate axes, first actuator means for providing a movement along the first particular axis relative to the platen, second actuator means for providing a movement along the second particular axis relative to the platen where the second particular axis is coordinate with the first particular axis, first pickoff means movable with the first and second actuator means and disposed relative to the platen for generating first periodic signals in accordance with the positioning of said first pickoff means along said first particular axis relative to the periodic function of said platen along said first particular axis, second pickoff means movable with the first and second actuator means and disposed relative to the platen for generating second periodic signals in accordance with the positioning of said second pickoff means along said second particular axis relative to the periodic function of said platen along said second particular axis, means for providing first command signals representing the desired positioning of said first and second actuator means and said first and second pickoff means along said first particular axis relative to said platen, means for providing second command signals representing the desired positioning of said first and second actuator means and said first and second pickoff means along said second particular axis relative to said platen, means for comparing the signals from said first pickoff means and said first command signals to produce first error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the first particular axis, first means for multiplying the first error signals and the signals from the first pickoff means for producing first periodic position control signals for controlling the operation of the first actuator means, means for driving said first actuator means along said first axis in accordance with the characteristics of said first periodic position control signals, means for comparing the output of said second pickoff means and said second command signals to produce second error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the second particular axis, second means for combining the second error signals and the signals from the second pickoff means for producing second periodic position control signals for controlling the operation of the second actuator means, means for driving said second actuator means along said second particular axis in accordance with the characteristics of said second periodic position control signals, wherein each of said first and second pickoff means includes means for generating a pair of pickoff signals having a particular phase difference and having a trigonometric function related to the positioning of said pickoff means along its particular axis relative to the platen and said means for providing command signals along each axis includes means for generating a pair of command signals having the particular phase difference and having a trigonometric function related to the desired positioning of said pickoff means along said platen, said first comparing means for generating the first error signals including means for generating a first pair of error signals having a trigonometric function and having the particular phasE difference and having characteristics in accordance with any difference between the associated pickoff and command signals in the pair, said second comparing means for generating the second error signals including means for generating a second pair of error signals having a trigonometric function and having the particular phase difference and having characteristics in accordance with any difference between the associated pickoff and command signals in the pair, said first means for producing the first position control signals including means for multiplying individual ones of the pair of pickoff signals from the first pickoff means and individual ones of the first pair of error signals to generate a first pair of position control signals having the particular phase difference, and said second means for producing the second position control signals including means for multiplying individual ones of the pair of pickoff signals from the second pickoff means and individual ones of the second pair of error signals to generate a second pair of pickoff signals.

Claim 16

The system set forth in claim 10, including, said pickoffs in said first and second pickoff means generating said pickoff signals at least in part in accordance with the rotation of said pickoffs, means responsive to said pickoff signals from the pickoffs at least a particular one of said first and second pickoff means for deriving additional position control signals in accordance with any difference between the outputs of said pickoffs as a result of any rotation of said pickoffs, and means responsive to the additional pickoff control signals for obtaining an operation of at least the particular one of the actuator means associated with the particular one of the pickoff means in accordance with such additional position control signals to inhibit rotation of the first and second pickoff means and the first and second actuator means about an axis substantially normal to a surface including the first and second particular axes.

Claim 17

In a closed loop control system, a platen constructed to define first and second energy levels in a periodic relationship along a particular axis, a head movable relative to the platen and disposed in contiguous relationship to the platen, first and second actuator means disposed on the head in a particular phase relationship to each other and to the platen and constructed to provide a movement of the head along the particular axis relative to the platen, first and second pickoff means disposed on the head in a particular phase relationship to each other and to the platen and connected to the actuator means and movable with the head and disposed relative to the platen for respectively generating first and second signals in accordance with the linear positioning of said pickoff means along the particular axis relative to said platen, said first and second pickoff means being disposed at opposite sides of the head relative to the first particular axis, means responsive to the signals from the first and second pickoff means for respectively deriving control signals from said oppositely positioned pickoff units in accordance with any difference between the characteristics of the signals from the pickoff means, means for combining in a particular relationship the control signals and the signals generated by said first and second pickoff means to produce anti-rotation control signals, the combining means including a first multiplier responsive to the control signals and the signals generated by the first pickoff means for generating first multiplication signals and including a second multiplier responsive to the control signals and the signals generated by the second pickoff means for generating second multiplication signals and further including a summer for adding the first and second multiplication signals to produce the anti-rotation control signals, and means for energizing said first and second actuator means in response To said anti-rotation control signals to inhibit rotation of said head relative to said platen about an axis substantially normal to a surface including the particular axis, said energizing means including a third multiplier responsive to said anti-rotation control signals and said first pickoff signals for generating third multiplication signals and including a fourth multiplier responsive to said anti-rotation control signals and said second pickoff signals for generating fourth multiplication signals and further including means responsive to said third and fourth multiplication signals for introducing said third and fourth multiplication signals respectively to said first and second actuation means to inhibit rotation of the head relative to the platen about the axis substantially normal to the surface including the particular axis.

Claim 18

In a closed loop control system, a platen constructed to define first and second energy levels in a periodic relationship along a particular axis, a head movable relative to the platen and disposed in contiguous relationship to the platen, first and second actuator means disposed on the head in a particular phase relationship to each other and to the platen and constructed to provide a movement of the head along the particular axis relative to the platen, first and second pickoff means disposed on the head in a particular phase relationship to each other and to the platen and connected to the actuator means and movable with the head and disposed relative to the platen for respectively generating first and second signals in accordance with the linear positioning of said pickoff means along the particular axis relative to said platen, said first and second pickoff means being disposed at opposite sides of the head relative to the first particular axis, means responsive to the signals from the first and second pickoff means for respectively deriving control signals from said oppositely positioned pickoff units in accordance with any difference between the characteristics of the signals from the pickoff means, means for combining in a particular relationship the control signals and the signals generated by said first and second pickoff means to produce anti-rotation control signals, the combining means including a first multiplier responsive to the control signals and the signals generated by the first pickoff means for generating first multiplication signals and including a second multiplier responsive to the control signals and the signals generated by the second pickoff means for generating second multiplication signals and further including a summer for adding the first and second multiplication signals to produce the anti-rotation control signals, and means for energizing said first and second actuator means in response To said anti-rotation control signals to inhibit rotation of said head relative to said platen about an axis substantially normal to a surface including the particular axis, said energizing means including a third multiplier responsive to said anti-rotation control signals and said first pickoff signals for generating third multiplication signals and including a fourth multiplier responsive to said anti-rotation control signals and said second pickoff signals for generating fourth multiplication signals and further including means responsive to said third and fourth multiplication signals for introducing said third and fourth multiplication signals respectively to said first and second actuation means to inhibit rotation of the head relative to the platen about the axis substantially normal to the surface including the particular axis.

Claim 19

In a system for providing a controlled relative movement between two members along first and second coordinators, the combination of: a first member constructed to define a periodic function along each of first and second coordinate axes, a second member disposed relative to the first member for simultaneous and yet independent displacement between the first and second members along each of the first and second coordinate axes relative to the displacement between the first and second members along the other coordinate axes, first means for providing first command signals representing the desired movement of the second member relative to the first member along the first axis, second means for providing second command signals representing the desired movement of the second member relative to the first member along the second axis, third means disposed on the second member to provide first periodic pickoff signals representing the actual movement of the second member relative to the periodic function defined by the first member along the first axis, fourth means disposed on the second member relative to the first means to provide second periodic pickoff signals representing the actual movement of the second member relative to the periodic function defined by the first member along the second axis, fifth means responsive to the first command and pickoff signals for producing first error signals in accordance with any differences between such command and pickoff signals, sixth means for multiplying the first error signals and the first pickoff signals to produce first periodic position control signals controlling the movement of the second member relative to the first member along the first particular axis, seventh means responsive to the first periodic position control signals for obtaining a movement of the second member relative to the first member along the first axis in accordance with the characteristics of the first periodic position control signals, eighth means responsive to the second command and pickoff signals for producing second error signals in accordance with any difference between such command and pickoff signals, ninth means for multiplying the second error signals and the second pickoff signals to produce second periodic position control signals controlling the movement of the second member relative to the first member along the second axis, and tenth means responsive to the second periodic position control signals for obtaining a movement of the second member relative to the first member along the second axis, simultaneously with the movement of the second member relative to the first member along the first axis, in accordance with the characteristics of the second periodic position control signals.

Claim 20

In a system for providing a controlled relative movement between two members along first and second coordinators, the combination of: a first member constructed to define a periodic function along each of first and second coordinate axes, a second member disposed relative to the first member for simultaneous and yet independent displacement between the first and second members along each of the first and second coordinate axes relative to the displacement between the first and second members along the other coordinate axes, first means for providing first command signals representing the desired movement of the second member relative to the first member along the first axis, second means for providing second command signals representing the desired movement of the second member relative to the first member along the second axis, third means disposed on the second member to provide first periodic pickoff signals representing the actual movement of the second member relative to the periodic function defined by the first member along the first axis, fourth means disposed on the second member relative to the first means to provide second periodic pickoff signals representing the actual movement of the second member relative to the periodic function defined by the first member along the second axis, fifth means responsive to the first command and pickoff signals for producing first error signals in accordance with any differences between such command and pickoff signals, sixth means for multiplying the first error signals and the first pickoff signals to produce first periodic position control signals controlling the movement of the second member relative to the first member along the first particular axis, seventh means responsive to the first periodic position control signals for obtaining a movement of the second member relative to the first member along the first axis in accordance with the characteristics of the first periodic position control signals, eighth means responsive to the second command and pickoff signals for producing second error signals in accordance with any difference between such command and pickoff signals, ninth means for multiplying the second error signals and the second pickoff signals to produce second periodic position control signals controlling the movement of the second member relative to the first member along the second axis, and tenth means responsive to the second periodic position control signals for obtaining a movement of the second member relative to the first member along the second axis, simultaneously with the movement of the second member relative to the first member along the first axis, in accordance with the characteristics of the second periodic position control signals.

Claim 21

The system set forth in claim 13, including eleventh means responsive to the first pickoff signals for inhibiting rotation of the second member relative to the first member about an axis transverse to a surface including the first and second coordinate axes, the first and second members being planar and being disposed in contiguous relationship to eAch other.

Claim 22

In the system set forth in claim 13, the other one of the first and second members having magnetic properties and the third and fourth means being provided with magnetizable properties for cooperating with the other one of the first and second members to provide the first and second periodic pickoff signals representing the relative movements between the first and second members along the first and second axes and the seventh and tenth means being provided with magnetizable properties for cooperating with the other one of the first and second members to obtain the desired movement of the second member relative to the first member respectively along the first and second axes.

Claim 23

In a system for providing a controlled relative movement between two members along a particular axis, the combination of: a first member constructed to provide first and second energy levels on a periodic basis along the particular axis, a second member disposed relative to the first member for displacement between the first and second members along the particular axis, first means for providing first and second signals having the periodic relationship and a particular phase relationship and representing a desired displacement between the first and second members along the particular axis, second means movable with the second member relative to the first member for providing first and second signals having the periodic relationship and a particular phase relationship to each other and to the periodic energy level on the first member and representing an actual displacement between the first and second members along the particular axis, third means operatively coupled to a particular one of the first and second members for obtaining a displacement between the first and second members along the particular axis, first servo means operatively coupled to the first and second means for producing a displacement of the second member relative to the first member along the particular axis in accordance with any difference between the desired and actual displacements of the second member relative to the first member along the particular axis, the first servo means including a first multiplier responsive to the first signals from the first and second means for producing a first multiplication signal and further including a second multiplier responsive to the second signals from the first and second means for producing a second multiplication signal and further including an adder responsive to the first and second multiplication signals for producing error signals and further including means responsive to the error signals for introducing such signals to the third means to obtain a displacement of the second member relative to the first member in accordance with such error signal, and second servo means operatively coupled to the second means for inhibiting rotation of the second member relative to the first member about an axis substantially perpendicular to a surface defined by the particular axis, the second servo means including means responsive to the first and second signals from the pickoff means for providing control signals representing any differences between such signals and further including a third multiplier responsive to the control signals and the signals from the first pickoff means for providing third multiplication signals and further including a fourth multiplier responsive to the control signals and the signals from the second pickoff means to provide fourth multiplication signals and further including a second adder responsive to the third and fourth multiplication signals for providing anti-rotation signals and further including means responsive to the anti-rotation signals for introducing such signals to the third means to obtain corrections in the displacement between the first and second members to inhibit any rotation of the second member relative to the first member about the axis substantially perpendicular to the surface defIned by the particular axis.

Claim 24

In a system for providing a controlled relative movement between two members along a particular axis, the combination of: a first member constructed to provide first and second energy levels on a periodic basis along the particular axis, a second member disposed relative to the first member for displacement between the first and second members along the particular axis, first means for providing first and second signals having the periodic relationship and a particular phase relationship and representing a desired displacement between the first and second members along the particular axis, second means movable with the second member relative to the first member for providing first and second signals having the periodic relationship and a particular phase relationship to each other and to the periodic energy level on the first member and representing an actual displacement between the first and second members along the particular axis, third means operatively coupled to a particular one of the first and second members for obtaining a displacement between the first and second members along the particular axis, first servo means operatively coupled to the first and second means for producing a displacement of the second member relative to the first member along the particular axis in accordance with any difference between the desired and actual displacements of the second member relative to the first member along the particular axis, the first servo means including a first multiplier responsive to the first signals from the first and second means for producing a first multiplication signal and further including a second multiplier responsive to the second signals from the first and second means for producing a second multiplication signal and further including an adder responsive to the first and second multiplication signals for producing error signals and further including means responsive to the error signals for introducing such signals to the third means to obtain a displacement of the second member relative to the first member in accordance with such error signal, and second servo means operatively coupled to the second means for inhibiting rotation of the second member relative to the first member about an axis substantially perpendicular to a surface defined by the particular axis, the second servo means including means responsive to the first and second signals from the pickoff means for providing control signals representing any differences between such signals and further including a third multiplier responsive to the control signals and the signals from the first pickoff means for providing third multiplication signals and further including a fourth multiplier responsive to the control signals and the signals from the second pickoff means to provide fourth multiplication signals and further including a second adder responsive to the third and fourth multiplication signals for providing anti-rotation signals and further including means responsive to the anti-rotation signals for introducing such signals to the third means to obtain corrections in the displacement between the first and second members to inhibit any rotation of the second member relative to the first member about the axis substantially perpendicular to the surface defIned by the particular axis.

Claim 25

In a system as set forth in claim 16, the first member being in the form of a magnetic grid and the second member being provided with magnetizable properties to cooperate with the magnetic grid in providing an actual displacement between the first and second members along the particular axis and the third means including magnetizable means cooperative with the magnetic grid for producing a displacement of the second member relative to the first member along the particular axis and the first means including magnetizable means cooperative with the magnetic grid for providing an indication of the actual displacement between the first and second members along the particular axis.

Claim 26

In a system as set forth in claim 16, the first and second members being planar and being disposed in contiguous relationship to each other, the third means including first and second actuating means having the particular phase relationship to each other and respectively responsive to the first and second signals from the pickoff means to provide a displacement of the second member relative to the first member along the particular axis.

Claim 27

In a system for providing a controlled relative movement between two members along first and second coordinate axes, the combination of: a first member, a second member disposed in spaced but contiguous relationship to the first member for simultaneous and yet independent displacement between the first and second members along each of the first and second coordinate axes relative to the displacement between the first and second members along the other one of the first and second coordinate axes, first means for indicating a desired displacement of the second member relative to the first member along the first coordinate axis, second means for indicating a desired displacement of the second member relative to the first member along the second coordinate axis, first servo means responsive to the desired displacement indicated by the first means and operable on a closed loop basis for producing the desired displacement of the second member relative to the first member along the first coordinate axis, second servo means responsive to the desired displacement indicated by the second means and operable on a closed loop basis for producing the desired displacement of the second member relative to the first member along the second coordinate axis, and third servo means operable on a closed loop basis for preventing rotation of the second member relative to the first member about an axis substantially perpendicular to a surface defined by the first and second coordinate axes.

Claim 28

In a system for providing a controlled relative movement between two members along first and second coordinate axes, the combination of: a first member, a second member disposed in spaced but contiguous relationship to the first member for simultaneous and yet independent displacement between the first and second members along each of the first and second coordinate axes relative to the displacement between the first and second members along the other one of the first and second coordinate axes, first means for indicating a desired displacement of the second member relative to the first member along the first coordinate axis, second means for indicating a desired displacement of the second member relative to the first member along the second coordinate axis, first servo means responsive to the desired displacement indicated by the first means and operable on a closed loop basis for producing the desired displacement of the second member relative to the first member along the first coordinate axis, second servo means responsive to the desired displacement indicated by the second means and operable on a closed loop basis for producing the desired displacement of the second member relative to the first member along the second coordinate axis, and third servo means operable on a closed loop basis for preventing rotation of the second member relative to the first member about an axis substantially perpendicular to a surface defined by the first and second coordinate axes.

Claim 29

In a system as set forth in claim 19, the first member being provided in the form of a grid having axes corresponding to the first and second axes and the first and second means respectively providing an indication of the desired displacement of the second member relative to the first member along the first and second coordinate axes of the grid and the first and second servo means respectively including means for providing an indication of the actual displacements of the second member relative to the first member along the first and second coordinate axes and further including first and second control means responsive to the indications of the actual and desired displacements of the second member relative to the first member along the first and second coordinate axes for producing controlled displacements between the first and second members along the first and second coordinate axes in accordance with any differences between the actual and desired displacements.

Claim 30

In a system as set forth in claim 20, the first and second members being planar and being disposed in contiguous relationship to each other and the first control means being responsive to the indications representing the actual displacement along the first coordinate axis and the difference between the actual and desireD displacements along the first coordinate axis for producing the controlled displacements between the first and second members along the first coordinate axis and the second control means being responsive to the indications representing the actual displacement along the second coordinate axis and the difference between the actual and desired displacements along the second coordinate axis for producing the controlled displacements between the first and second members along the second coordinate axis.

Claim 31

In a system as set forth in claim 21, the first member being magnetic and the first and second servo means respectively including first and second magnetic means disposed on the second member for cooperating with the first member to produce the desired displacements of the second member relative to the first member along the first and second coordinate axes.

Claim 32

A closed loop control system for controlling the positioning of an actuator along a particular axis on a platen constructed to provide a periodic function along the particular axis, including: pickoff means connected to the actuator and movable therewith and disposed relative to the platen for generating periodic signals in accordance with the positioning of said pickoff means relative to the periodic function of said platen along said particular axis on said platen, means for providing command signals representing the desired positioning of said actuator along said particular axis on said platen, means for comparing the output of said pickoff means with said command signals to produce error signals representing differences between the desired and actual displacements of the pickoff means relative to the platen along the particular axis, means for multiplying the error signals and the signals from the pickoff means for producing position control signals for controlling the operation of said actuator, means for driving said actuator along said particular axis relative to said platen in response to said position control signals, and means responsive to said pickoff means for generating signals in accordance with any rotation of said actuator about an axis transverse to said platen, said rotation signals being introduced to said actuator to provide a drive force to said actuator to inhibit the rotation thereof about an axis substantially perpendicular to a surface including said particular axis.

Claim 33

A closed loop control system for controlling the positioning of an actuator along a particular axis on a platen constructed to provide a periodic function along the particular axis, including: pickoff means connected to the actuator and movable therewith and disposed relative to the platen for generating periodic signals in accordance with the positioning of said pickoff means relative to the periodic function of said platen along said particular axis on said platen, means for providing command signals representing the desired positioning of said actuator along said particular axis on said platen, means for comparing the output of said pickoff means with said command signals to produce error signals representing differences between the desired and actual displacements of the pickoff means relative to the platen along the particular axis, means for multiplying the error signals and the signals from the pickoff means for producing position control signals for controlling the operation of said actuator, means for driving said actuator along said particular axis relative to said platen in response to said position control signals, and means responsive to said pickoff means for generating signals in accordance with any rotation of said actuator about an axis transverse to said platen, said rotation signals being introduced to said actuator to provide a drive force to said actuator to inhibit the rotation thereof about an axis substantially perpendicular to a surface including said particular axis.

Claim 34

A closed loop system including: a platen constructed to provide a periodic function along each of first and second coordinate axes, first actuator means for providing a movement along the first particular axis relative to the platen, second actuator means for providing a movement along the second particular axis relative to the platen where the second particular axis is coordinate with the first particular axis, first pickoff means movable with the first and second actuator means and disposed relative to the platen for generating first periodic signals in accordance with the positioning of said first pickoff means along said first particular axis relative to the periodic function of said platen along said first particular axis, second pickoff means movable with the first and second actuator means and disposed relative to the platen for generating second periodic signals in accordance with the positioning of said second pickoff means along said second particular axis relative to the periodic function of said platen along said second particular axis, means for providing first command signals representing the desired positioning of said first and second actuator means and said first and second pickoff means along said first particular axis relative to said platen, means for providing second command signals representing the desired positioning of said first and second actuator means and said first and second pickoff means along said second particular axis relative to said platen, means for comparing the signals from said first pickoff meanS and said first command signals to produce first error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the first particular axis, first means for multiplying the first error signals and the signals from the first pickoff means for producing first periodic position control signals for controlling the operation of the first actuator means, means for driving said first actuator means along said first axis in accordance with the characteristics of said first periodic position control signals, means for comparing the output of said second pickoff means and said second command signals to produce second error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the second particular axis, second means for combining the second error signals and the signals from the second pickoff means for producing second periodic position control signals for controlling the operation of the second actuator means, means for driving said second actuator means along said second particular axis in accordance with the characteristics of said second periodic position control signals, means responsive to the signals from at least a particular one of said first and second pickoff means for generating signals having characteristics in accordance with any rotation of said first and second pickoff means and said first and second actuator means about an axis substantially perpendicular to a surface including the first and second axes, and means responsive to the signals from the last mentioned means for introducing such signals to at least a particular one of the first and second actuator means to provide a force to said particular one of said actuator means for inhibiting the rotation of said pickoff means and actuator means about the axis substantially perpendicular to a surface including the first and second particular axis.

Claim 35

A closed loop system including: a platen constructed to provide a periodic function along each of first and second coordinate axes, first actuator means for providing a movement along the first particular axis relative to the platen, second actuator means for providing a movement along the second particular axis relative to the platen where the second particular axis is coordinate with the first particular axis, first pickoff means movable with the first and second actuator means and disposed relative to the platen for generating first periodic signals in accordance with the positioning of said first pickoff means along said first particular axis relative to the periodic function of said platen along said first particular axis, second pickoff means movable with the first and second actuator means and disposed relative to the platen for generating second periodic signals in accordance with the positioning of said second pickoff means along said second particular axis relative to the periodic function of said platen along said second particular axis, means for providing first command signals representing the desired positioning of said first and second actuator means and said first and second pickoff means along said first particular axis relative to said platen, means for providing second command signals representing the desired positioning of said first and second actuator means and said first and second pickoff means along said second particular axis relative to said platen, means for comparing the signals from said first pickoff meanS and said first command signals to produce first error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the first particular axis, first means for multiplying the first error signals and the signals from the first pickoff means for producing first periodic position control signals for controlling the operation of the first actuator means, means for driving said first actuator means along said first axis in accordance with the characteristics of said first periodic position control signals, means for comparing the output of said second pickoff means and said second command signals to produce second error signals representing any differences between the desired and actual positioning of the first and second actuator means relative to the platen along the second particular axis, second means for combining the second error signals and the signals from the second pickoff means for producing second periodic position control signals for controlling the operation of the second actuator means, means for driving said second actuator means along said second particular axis in accordance with the characteristics of said second periodic position control signals, means responsive to the signals from at least a particular one of said first and second pickoff means for generating signals having characteristics in accordance with any rotation of said first and second pickoff means and said first and second actuator means about an axis substantially perpendicular to a surface including the first and second axes, and means responsive to the signals from the last mentioned means for introducing such signals to at least a particular one of the first and second actuator means to provide a force to said particular one of said actuator means for inhibiting the rotation of said pickoff means and actuator means about the axis substantially perpendicular to a surface including the first and second particular axis.