Open loop stepping motor acceleration-deceleration control

Claim 2

An open loop paper motion control system for use in a printer comprising: a stepping motor for advancing paper in continuous motion through any number of lines of print; time measuring means for providing outputs at predetermined periods of time corresponding to switching times of said stepping motor which provide maximum acceleration, and controlled deceleration of said paper through each of said any number of lines of print; control unit means for selecting one of said any number of lines of print; switching means connected to a power supply, to said motor, to said control unit means, and to said time measuring means for selectively switching power from said power supply to windings of said motor at those of said predetermined periods of time which provide maximum acceleration and controlled deceleration of said paper through said selected one of said any number of lines of print.

Claim 3

The open loop paper motion control system of claim 1 wherein said time measuring means further comprises compensating means, compensating for changes in the voltage of said power supply by changing said predetermined periods of time to be inversely proportional to the voltage of said power supply.

Claim 4

The open loop paper motion control system of claim 1 wherein said control unit means further comprises: time delay means connected to the output of said control unit means which selects said one of said any number of lines of print for inhibiting printing that amount of time required for said paper to come to rest after having been moved said one of said any number of lines of print.

Claim 5

A logic system for controlling the operation of a stepping motor having a known load to provide controlled motion of said motor and load without feedback comprising: time measuring means for providing outputs at predetermined periods of time corresponding to switching angles of said motor which provide maximum acceleration and controlled deceleration of said motor and load through each number of a plurality of numbers of steps; enabling means for selecting a sequence of said outputs at predetermined periods of time corresponding to said switching angles when said motor and load move continuously through a number of steps of said plurality of numbers of steps; switching means connected to said time measuring means, to said enabling means, to a power supply, and to said motor, for selectively switching power from said power supply to windings of said motor whenever outputs of said selected sequence of outputs is received from said time measuring means.

Claim 6

A logic system for controlling the operation of a stepping motor having a known load to provide controlled motion of said motor and load without feedback comprising: time measuring means for providing outputs at predetermined periods of time corresponding to switching angles of said motor which provide maximum acceleration and controlled deceleration of said motor and load through each number of a plurality of numbers of steps; enabling means for selecting a sequence of said outputs at predetermined periods of time corresponding to said switching angles when said motor and load move continuously through a number of steps of said plurality of numbers of steps; switching means connected to said time measuring means, to said enabling means, to a power supply, and to said motor, for selectively switching power from said power supply to windings of said motor whenever outputs of said selected sequence of outputs is received from said time measuring means.

Claim 7

The logic system of claim 4 wherein said time measuring means includes compensation means, compensating for variations in the voltage provided by said power supply by varying said predetermined periods of time to be indirectly proportional to the voltage of said power supply.

Claim 8

The logic system of claim 5 wherein said time measuring means further includes: a ramp generator for generating a ramp waveform; said ramp generator including said compensation means for controlling the output of said ramp generator to be directly proportional tO said voltage of said power supply; comparing means connected to said ramp generator for providing outputs when said output of said ramp generator has reached predetermined levels.

Claim 9

The logic system of claim 5 wherein said time measuring means is digital.

Claim 12

The method of claim 8 wherein said selectively connecting step further comprises the steps of: selecting a first sequence of predetermined amounts; sequentially switching power from said power supply to windings of said motor as each selected predetermined amount, of said first sequence of predetermined amounts, is accumulated in said accumulator to provide continuous motion of said motor through a first number of steps; selecting a second sequence of predetermined amounts; sequentially switching power from said power supply to windings of said motor as each selected predetermined amount, of said second sequence of predetermined amounts, is accumulated in said accumulator to provide continuous motion of said motor through a second number of steps.

Claim 13

The method of controlling a motor as in claim 6 to provide continuous motion of said motor from any one to any other one of a plurality of equilibrium angles; wherein said accumulating step of claim 6 further comprises the steps of: a. accumulating at a positive rate equal to said accumulation rate until a first predetermined amount has been accumulated within said accumulator; b. accumulating at a negative rate equal to said accumulation rate until an second predetermined amount has been accumulated within said accumulator; c. accumulating at said positive rate until said first predetermined amount has been restored to said accumulator whenever said running velocity is to be maintained; d. repeating steps (b) and (c) while said running velocity is to be maintained; e. accumulating at said negative rate until a third predetermined amount has been accumulated within said accumulator when deceleration of said motor is desired; and wherein said selectively connecting step of claim 6 further comprises the steps of: f. connecting said power supply to selected windings of said motor in sequence as a first sequence of predetermined amounts are accumulated within said accumulator, to provide maximum acceleration of said motor; g. connecting said power supply to a selected winding of said motor when a fourth predetermined amount has been accumulated within said accumulator to provide that predetermined amount of acceleration necessary for said motor to reach running velocity when loaded with said known load; h. repeatedly connecting said power supply to selected windings of said motor in sequence as a second sequence of predetermined amounts are repeatedly accumulated within said accumulator while said running velocity is to be maintained; i. connecting said power supply to selected windings of said motor in sequence as a third sequence of predetermined amounts are accumulated within said accumulator to provide controlled deceleration of said motor while loaded with said known load to allow said motor to come to rest at a preselected one of any one of said equilibrium angles.

Claim 16

The method of claim 11 further comprising the steps of: d. generating a second sequence of outputs whenever predetermined amounts have been accumulated within said accumulator, said outputs corresponding to switching times of said stepping motor which provide maximum acceleration and controlled deceleration of said motor and load through a second number of steps; e. selectively connecting power from said power supply to said windings of said motor whenever outputs of said second sequence of outputs are generated to provide maximum acceleration and controlled deceleration of said motor and load through said second number of stages.

Claim 19

The method of claim 13 wherein said positive and said negative accumulation rates are directly proportional to the output voltage of said power supply in order to compensate for variations in torque produced by said motor which are caused by variations in the output voltage of said power supply.

Claim 20

The method of claim 14 wherein said positive and said negative accumulation rates are equal.

Claim 21

The method of claim 13 further comprising the additional steps, between step (c) and step (d), of: c1. generating at least one controlled acceleration output, said controlled acceleration output corresponding to a switching time of said motor which provides controlled acceleration of said motor and load to reach running velocity without overshoot and without excessive oscillation about said running velocity; c2. selectively connecting power from said power supply to windings of said motor whenever said additional output is generated to provide said controlled acceleration; c3. accumulating in said accumulator alternately at a negative rate and at a positive rate; c4. generating running outputs corresponding to switching times of said motor which provide a net positive torque equal to friction of said Motor and load; c5. selectively connecting power from said power supply to windings of said motor whenever said running outputs are generated to provide said net positive torque.