Position sensing apparatus with continuous update

Claim 2

Apparatus for producing an output signal at an output terminal, the output signal being a representation of an actual position signal that is updated at intervals, comprising: position error means, responsive to the output signal and to the actual position signal, for generating a rate signal that changes in accordance with the difference between the actual position signal and the output signal; and position computation means, responsive to said rate signal and coupled to the output terminal, for generating the output signal, for changing the output signal at a rate representative of said rate signal, and for updating the output signal a plurality of times for each time that the actual position signal is updated; said position error means changing said rate signal in a manner tending to null the difference between the actual position signal and the output signal at the times when the actual position signal is updated.

Claim 3

The apparatus of claim 1 wherein said position error means operates to store at least one previous value of said difference and to change said rate signal by an amount that depends on the current value of said difference and said at least one previous value of said difference.

Claim 4

The apparatus of claim 1 wherein said position computation means operates to change the output signal at a rate proportional to the value of said rate signal.

Claim 5

The apparatus of claim 1 wherein said position error means is incorporated in a programmed digital processor.

Claim 6

Apparatus comprising: position means for providing an actual position signal that is updated at intervals; position error means, having a primary signal input and a feedback signal input and being responsive to signals at said primary and feedback signal inputs, for generating a rate signal that changes in accordance with an error signal representing the difference between signals present at said primary and feedback signal inputs; position computation means, having a rate signal input and being responsive to signals at said rate signal input, for generating a computed signal that changes at a rate corresponding to signals present at said rate signal input and that is updated a plurality of times for each time that the actual position signal is updated; and means for communicating said actual position signal to said primary signal input, said rate signal to said rate signal input, and said computed signal to said feedback signal input, whereupon said position computation means varies said computed signal so as to null said error signal.

Claim 7

Apparatus comprising: position means for providing an actual position signal that is updated at intervals; position error means, having a primary signal input and a feedback signal input and being responsive to signals at said primary and feedback signal inputs, for generating a rate signal that changes in accordance with an error signal representing the difference between signals present at said primary and feedback signal inputs; position computation means, having a rate signal input and being responsive to signals at said rate signal input, for generating a computed signal that changes at a rate corresponding to signals present at said rate signal input and that is updated a plurality of times for each time that the actual position signal is updated; and means for communicating said actual position signal to said primary signal input, said rate signal to said rate signal input, and said computed signal to said feedback signal input, whereupon said position computation means varies said computed signal so as to null said error signal.

Claim 8

The apparatus of claim 5 wherein said position means comprises: timing means for generating an excitation signal at a first frequency and a counter signal at a second frequency that is a given multiple of said first frequency; position sensor means, responsive to a position to be sensed and to said excitation signal, for providing a sensor signal; counter means, responsive to said counter signal, for counting at said second frequency; and latch means, responsive to said sensor signal, for latching the content of said counter, the latched value of which constitutes said actual position signal.

Claim 9

The apparatus of claim 5 wherein said position error means operates to store at least one previous value of said error signal and to change said rate signal by an amount that depends on the current value and said at least one previous value of said error signal.

Claim 10

The apparatus of claim 5 wherein said position computation means operates to change said computed signal at a rate proportional to the value of said rate signal.

Claim 11

The apparatus of claim 5 wherein said position error means is incorporated in a programmed digital processor.

Claim 12

Apparatus comprising: position means for providing an actual position signal that is updated at intervals and an interrupt signal specifying that the actual position signal is being updated; position error means, having a primary signal input, an interrupt signal input, and a feedback signal input and being responsive to signals at said primary, interrupt, and feedback signal inputs, for generating a rate signal that changes in accordance with an error signal representing the difference between signals present at said primary and feedback signal inputs; position computation means, having a rate signal input and being responsive to signals at said rate signal input, for generating a computed signal that changes at a rate corresponding to signals present at said rate signal input and that is updated a plurality of times for each time that the actual position signal is updated; and means for communicating said actual position signal to said primary signal input, said interrupt signal to said interrupt signal input, said rate signal to said rate signal input, and said computed signal to said feedback signal input, whereupon said position computation means varies said computed signal so as to null said error signal.

Claim 13

Apparatus comprising: position means for providing an actual position signal that is updated at intervals and an interrupt signal specifying that the actual position signal is being updated; position error means, having a primary signal input, an interrupt signal input, and a feedback signal input and being responsive to signals at said primary, interrupt, and feedback signal inputs, for generating a rate signal that changes in accordance with an error signal representing the difference between signals present at said primary and feedback signal inputs; position computation means, having a rate signal input and being responsive to signals at said rate signal input, for generating a computed signal that changes at a rate corresponding to signals present at said rate signal input and that is updated a plurality of times for each time that the actual position signal is updated; and means for communicating said actual position signal to said primary signal input, said interrupt signal to said interrupt signal input, said rate signal to said rate signal input, and said computed signal to said feedback signal input, whereupon said position computation means varies said computed signal so as to null said error signal.

Claim 14

The apparatus of claim 10 wherein said position means comprises: timing means for generating an excitation signal at a first frequency and a counter signal at a second frequency that is a given multiple of said first frequency; position sensor means, responsive to a position to be sensed and to said excitation signal, for providing a sensor signal; counter means, responsive to said counter signal, for counting at said second frequency; and latch means, responsive to said sensor signal, for latching the content of said counter, the latched value of which constitutes said actual position signal.

Claim 15

The apparatus of claim 10 wherein said position error means operates to store at least one previous value of said error signal and to change said rate signal by an amount that depends on the current value and said at least one previous value of said error signal.

Claim 16

The apparatus of claim 10 wherein said position computation means operates to change said computed signal at a rate proportional to the value of said rate signal.

Claim 17

The apparatus of claim 10 wherein said position error means is incorporated in a programmed digital processor.

Claim 20

The method of claim 15 wherein at least one previous value of the difference is stored and the rate signal is changed by an amount that depends on the current value of the difference and the at least one previous value of the difference.

Claim 21

The method of claim 15 wherein the output signal is changed at a rate proportional to the value of the rate signal.

Claim 22

The method of claim 15 wherein said generating and changing steps are performed in a programmed digital processor.

Claim 25

The method of claim 19 wherein said providing step comprises the substeps of: providing a position sensor; generating an excitation signal at a first frequency and a counter signal at a second frequency that is a given multiple of the first frequency; exciting the position sensor to provide a sensor signal; incrementing a count at said second frequency; and storing the count at a predetermined portion of the sensor signal cycle, the stored count defining the actual position signal.

Claim 26

The method of claim 19 wherein at least one previous value of the difference is stored and the rate signal is changed by an amount that depends on the current value of the difference and the at least one previous value of the difference.

Claim 27

The method of claim 19 wherein the position output signal is changed at a rate proportional to the value of the rate signal.

Claim 28

The method of claim 19 wherein said generating and changing steps are performed in a programmed digital processor.