Apparatus for controlling the relative position between two relatively movable members

Claim 2

Apparatus for controlling the relative position between two relatively movable members comprising: transducer means coupled to said movable members for producing two cyclic position signals displaced in space phase from each other each cycle of said signals being indicative of a predetermined unit of relative movement of said members; motor means for providing a change in said relative position between said two movable members; logic means coupled to said transducer means and responsive to said two cyclic position signals to provide a logic signal centered on a predetermined point of one of said cyclic position signals corresponding to the end of said unit of movement; and control means coupled to said transducer means and responsive to said logic signal and a reference signal to cause said motor means to stop said relative movement at the end of a predetermined unit of movement.

Claim 3

Apparatus as in claim 1 in which said position signals are in space quadrature.

Claim 4

Apparatus for controlling the relative position between two members relatively movable in two directions comprising: transducer means coupled to said movable members for producing at least one cyclic position signal each cycle of said signal being indicative of a predetermined unit of relative movement of said members; counter means for counting said cycles of said cyclic position signal and providing an output signal in response to a predetermined number of cycles being counted; logic means coupled to said transducer means and responsive to at least said one cyclic position signal to provide a symmetrical logic signal centered on a predetermined point of said cyclic position signal corresponding to the end of said unit of movement; motor means for providing the change in relative position between said two movable members; and gating means responsive to the coincidence of the centered portion of said logic signal and said output signal of said counter means for coupling said position signal to said motor means to cause said motor means to stop said relative movement at the end of the present unit of movement, whereby said movement may be automatically stopped at the end of a unit of movement with said members moving in either of said two directions.

Claim 5

Apparatus for controlling the relative position between two members relatively movable in two directions comprising: transducer means coupled to said movable members for producing at least one cyclic position signal each cycle of said signal being indicative of a predetermined unit of relative movement of said members; counter means for counting said cycles of said cyclic position signal and providing an output signal in response to a predetermined number of cycles being counted; logic means coupled to said transducer means and responsive to at least said one cyclic position signal to provide a symmetrical logic signal centered on a predetermined point of said cyclic position signal corresponding to the end of said unit of movement; motor means for providing the change in relative position between said two movable members; and gating means responsive to the coincidence of the centered portion of said logic signal and said output signal of said counter means for coupling said position signal to said motor means to cause said motor means to stop said relative movement at the end of the present unit of movement, whereby said movement may be automatically stopped at the end of a unit of movement with said members moving in either of said two directions.

Claim 6

Apparatus as in claim 3 where said counter means is a difference type counter which is preset to a predetermined number and provides said output signal in response to an equivalent number of cycles being counted.

Claim 7

Apparatus as in claim 3 where said position signal is electrical and has a substantially sinusoidal waveform.

Claim 8

Apparatus as in claim 3 where said logic means is coupled to said counter means and said symmetrical logic signal drives said counter means to produce said output signal.

Claim 9

Apparatus as in claim 3 where said gating means includes field effect transistor switching means responsive to said coincidence for coupling said position signal to said motor means whereby said analog position signal is controlled by said digital logic signal.

Claim 10

Apparatus as in claim 3 where said logic means is responsive to two of said position signals which are displaced from each other in space phase.

Claim 11

Apparatus as in claim 8 where said logic means includes means for inverting one of said position signals, means for summing the other position signal with both said inverted and uninverted one position signal and means for squaring and logically ANDing the two resultant summed signals for providing said symmetrical logic signal centered on a zero crossing of said other position signal.

Claim 12

Apparatus as in claim 9 where said logic means includes means for squaring said summed position signals.

Claim 13

Apparatus as in claim 9 for attenuating one of said position signals relative to the other, whereby the width of the centered portion of said symmetrical logic signal may be predetermined.