High resolution stepping motor drive

Claim 3

A stepping motor control circuit for stepping motors having a given number of windings for selecting the rest position of the motor comprising, in combination: a control circuit for generating a given number of control signals; a given number of driver circuits each coupled to a unique winding and responsive to the magnitude of one said control signal to drive the winding coupled thereto with a signal whose magnitude is directly related to the magnitude of the control signal; said control circuit including: means to maintain a selectable magnitude control signal to each coupled driver starting at a time just before one adjacent winding driver circuit produces a descending staircase signal with at least one step until just after the time the other adjacent winding driver circuit produces an ascending staircase signal with at least one step, said control circuit means producing an ascending staircase signal with at least one step after a non-adjacent winding driver circuit has completed a descending staircase signal with at least one step and producing a descending staircase signal with at least one step after said other adjacent winding driver circuit has completed its ascending staircase signal with at least one step, said control circuit including means to select the total number of steps in all said ascending and all said discending staircase signals.

Claim 4

A stepping motor control circuit for stepping motors having a given number of windings for selecting the rest position of the motor comprising, in combination: a control circuit for generating a given number of control signals; a given number of driver circuits each coupled to a unique winding and responsive to the magnitude of one said control signal to drive the winding coupled thereto with a signal whose magnitude is directly related to the magnitude of the control signal; said control circuit including: means to maintain a selectable magnitude control signal to each coupled driver starting at a time just before one adjacent winding driver circuit produces a descending staircase signal with at least one step until just after the time the other adjacent winding driver circuit produces an ascending staircase signal with at least one step, said control circuit means producing an ascending staircase signal with at least one step after a non-adjacent winding driver circuit has completed a descending staircase signal with at least one step and producing a descending staircase signal with at least one step after said other adjacent winding driver circuit has completed its ascending staircase signal with at least one step, said control circuit including means to select the total number of steps in all said ascending and all said discending staircase signals.

Claim 5

The stepping motor control of claim 1 wherein said selectable magnitude is not greater than that required to make the coupled driver circuit produce saturation in the stepping motor winding coupled thereto.

Claim 6

The stepping motor control of claim 1 wherein each ascending staircase signal has N steps and each descending staircase has N steps where N is a selectable digit.

Claim 7

The stepping motor control of claim 4 wherein said steps each take the same amount of time.

Claim 8

The stepping motor control of claim 5 wherein said selectable magnitude control signal has a duration equal to that in which 2N + 1 steps could occur.

Claim 9

The stepping motor control of claim 1 including step amplitude control means to adjust the amplitude of each step in said ascending and said descending staircase signal so that the amplitude of each step is not always equal to the amplitude of each other step.

Claim 10

The stepping motor control of claim 1 wherein the amplitude of each step is equal to the amplitude of each other step in said ascending and said descending staircase signal.

Claim 11

The stepping motor control of claim 1 wherein said control means maintains said control signals after the last step of said selectable number of steps at the same magnitude achieved thereby during said last step.

Claim 12

A control circuit for selecting the rest postion of a stepping motor comprising, in combination: means to produce a series of N pulses in a finite pulse string where N is a selectable number; first counter means responsive to said pulse producing means to repetitively count pulses in a first direction starting at zero and continuing in said first direction to a selectable value M and thereafter count in the opposite direction from M to zero; second counter means responsive to said pulse producing means to repetitively count said pulses in said opposite direction starting at M and continuing to zero and thereafter counting in said first direction from zero to M; a driver circuit means coupled to each winding in the stepping motor; means responsive to both said counters to cause repetitive production of an ascending staircase signal with M steps by said driver means in successively adjacent windings of the stepping motor while said first counter counts from zero to M; means responsive to both said counters to cause production of a descending staircase signal with M steps by the driver circuit coupled to the windings energized by the second preceding ascending staircase signal while said second counter counts from M to zero; and means responsive to both said counters to energize the winding coupled to a given driver circuit means at a constant level following an ascending staircase signal and preceeding a descending staircase signal coupled to said given winding.

Claim 13

A control circuit for selecting the rest postion of a stepping motor comprising, in combination: means to produce a series of N pulses in a finite pulse string where N is a selectable number; first counter means responsive to said pulse producing means to repetitively count pulses in a first direction starting at zero and continuing in said first direction to a selectable value M and thereafter count in the opposite direction from M to zero; second counter means responsive to said pulse producing means to repetitively count said pulses in said opposite direction starting at M and continuing to zero and thereafter counting in said first direction from zero to M; a driver circuit means coupled to each winding in the stepping motor; means responsive to both said counters to cause repetitive production of an ascending staircase signal with M steps by said driver means in successively adjacent windings of the stepping motor while said first counter counts from zero to M; means responsive to both said counters to cause production of a descending staircase signal with M steps by the driver circuit coupled to the windings energized by the second preceding ascending staircase signal while said second counter counts from M to zero; and means responsive to both said counters to energize the winding coupled to a given driver circuit means at a constant level following an ascending staircase signal and preceeding a descending staircase signal coupled to said given winding.

Claim 14

The stepping motor control circuit of claim 10 wherein the magnitude of said constant level is not greater than the level at which any winding of the stepping motor becomes saturated.

Claim 15

The stepping motor control of claim 10 wherein the duration of each said step is the same for all steps.

Claim 16

The stepping motor control of claim 10 wherein the magnitude of each said step is the same for all steps.

Claim 17

The control circuit of claim 10 including step amplitude control means to selectably adjust the amplitude of each step in each said ascending and each said descending staircase signal so that each step is not always equal to the amplitude of each other step.

Claim 18

A control circuit for energizing a plurality of windings of a stepping motor comprising, in combination: means to produce series of N pulses in a finite pulse string where N is selectable whole number; first counter means responsive to said pulse producing means to repetitively count pulses in a first direction starting at zero and continuing in said first direction to a selectable value M and thereafter count in the opposite direction from M to zero; second counter means responsive to said pulse producing means to repetitively count said pulses in said oposite direction starting at M and counting to zero and thereafter counting in said first direction from zero to M; a driver circuit means coupled to each winding in th stepping motor; means responsive to both said counters to produce an ascending staircase signal with M steps by one said driver means at a time, each said driver means producing such ascending staircase signal while said first counter counts from zero to M and following completion of an ascending staircase signal by a given adjacent driver means; means responsive to said first and said second counter to produce a descending staircase signal with M steps by one said driver means at a time, each said driver means producing such descending staircase signal while said second counter counts from M to zero and following completion of a descending staircase signal by said given adjacent driver means; means responsive to both said counters to product a selectable level signal by each said driver circuit for the time period following an ascending staircase signal and preceding a descending staircase signal produced by the same driver circuit.

Claim 19

A control circuit for energizing a plurality of windings of a stepping motor comprising, in combination: means to produce series of N pulses in a finite pulse string where N is selectable whole number; first counter means responsive to said pulse producing means to repetitively count pulses in a first direction starting at zero and continuing in said first direction to a selectable value M and thereafter count in the opposite direction from M to zero; second counter means responsive to said pulse producing means to repetitively count said pulses in said oposite direction starting at M and counting to zero and thereafter counting in said first direction from zero to M; a driver circuit means coupled to each winding in th stepping motor; means responsive to both said counters to produce an ascending staircase signal with M steps by one said driver means at a time, each said driver means producing such ascending staircase signal while said first counter counts from zero to M and following completion of an ascending staircase signal by a given adjacent driver means; means responsive to said first and said second counter to produce a descending staircase signal with M steps by one said driver means at a time, each said driver means producing such descending staircase signal while said second counter counts from M to zero and following completion of a descending staircase signal by said given adjacent driver means; means responsive to both said counters to product a selectable level signal by each said driver circuit for the time period following an ascending staircase signal and preceding a descending staircase signal produced by the same driver circuit.

Claim 20

The stepping motor control of claim 15 wherein the number M is a selectable number of steps.

Claim 23

energizing the fourth winding with said constant current and said first winding with a multi-step ascending staircase current beginning at zero and ending at said constant current during a seventh output state; 8. energizing said first winding with said constant current and said fourth winding with a multi-step descending staircase current beginning at said constant current and ending at zero during a eighth output state; and 9. repetitively executing steps 1-8 to the extent that the total number of steps in all ascending and all descending staircase currents does not exceed N where N is a selectable whole number.

Claim 24

energizing the fourth winding with said constant current and said first winding with a multi-step ascending staircase current beginning at zero and ending at said constant current during a seventh output state; 8. energizing said first winding with said constant current and said fourth winding with a multi-step descending staircase current beginning at said constant current and ending at zero during a eighth output state; and 9. repetitively executing steps 1-8 to the extent that the total number of steps in all ascending and all descending staircase currents does not exceed N where N is a selectable whole number.

Claim 27

energizing said second winding with said constant current and energizing said third winding with a multi-step descending staircase current beginning at said constant current and ending at zero during a sixth output state; 7. energizing the second winding with said constant current and said first winding with a multi-step ascending staircase current beginning at zero and ending at said constant current during a seventh output state; 8. energizing the first winding with said constant current and the second winding with a multi-step descending staircase signal beginning at said constant current and ending at zero during an eight output state; and 9. repetitively executing steps 1-8 to the extent that the total number of steps in all ascending and all descending staircase currents does not exceed a selectable whole number N.

Claim 28

energizing said second winding with said constant current and energizing said third winding with a multi-step descending staircase current beginning at said constant current and ending at zero during a sixth output state; 7. energizing the second winding with said constant current and said first winding with a multi-step ascending staircase current beginning at zero and ending at said constant current during a seventh output state; 8. energizing the first winding with said constant current and the second winding with a multi-step descending staircase signal beginning at said constant current and ending at zero during an eight output state; and 9. repetitively executing steps 1-8 to the extent that the total number of steps in all ascending and all descending staircase currents does not exceed a selectable whole number N.