Stepper motor control apparatus
AssigneeRockwell International Corporation
InventorMelvin H. Rhodes
Life of this patent
Estimating the term…
Abstract
A control system using a duty cycle converter to convert an analog input into both a second order or velocity squared feedback as well as a set of clockwise and counterclockwise pulse trains the frequency of which is dependent upon the amplitude of the input signal. The velocity squared feedback is augmented by a position feedback from a stepper motor to provide optimum operation. To obtain optimum performance from a stepper motor, the rate of change of input pulses must not exceed a predetermined value for starting or stopping or the motor will react improperly to some of the pulses. The present system provides a linear increase in the step rate to a maximum and then a linear decrease in the step rate such that there is no overshoot beyond the requested analog input signal.
Claims6
Apparatus for controlling a position indicating motor means comprising, in combination:
- limiting means, including input means and output means;
- first signal supplying means for supplying a control signal connected to said input means of limiting means;
- integrating means, including input means and output means, said input means thereof connected to said output means of said limiting means;
- signal converting means, including input means and first, second and third output means, a signal appearing at said first output means being representative of the square of a signal being supplied to said input means thereof and pulse signals appearing at said second and third output means being representative in frequency of the amplitude of the signal being supplied to said input means thereof and respectively representing the polarity of the signal being supplied to said input means thereof;
- means connecting said output means of said integrating means to said input means of said signal converting means;
- motor means including input means connected to said second and third output means of said signal converting means, said motor means being actuated a prescribed amount upon receipt of each pulse and in a direction corresponding to which of said second and third means is supplying pulse signals;
- position feedback signal means connected to said motor means and supplying a signal indicative of the position of said motor means with respect to a reference;
- and
- summing means for summing signals from said position feedback signal means and said first output means of signal converting means to said input means of said limiting means.
Servo-mechanism apparatus comprising, in combination:
- summing means including first, second and third input means and output means for supplying a composite output signal which is a function of signals supplied to said inputs;
- control signal supplying means for supplying an analog position control signal to said first input means;
- first signal converting means connected between said output means and said second input means for supplying thereto a signal indicative of the square of said composite signal;
- and
- second signal converting means, including signal responsive motor means and position indicating means, connected between said output means and said third input means, said motor means responding to said composite signal from said summing means and said position indicating means providing a position output signal to said third input means which changes in response to actuation of said motor means.
Servo-mechanism apparatus comprising, in combination:
- summing means including first, second and third input means and output means for supplying a composite output signal which is a function of signals supplied to said inputs;
- control signal supplying means for supplying an analog position control signal to said first input means;
- and
- signal converting means connected between said output means and said second input means for supplying thereto a first signal indicative of the square of said composite signal, and including signal responsive motor means and position indicating means, connected to said third input means, said motor means responding to said composite signal from said summing means and said position indicating means providing a position output second signal to said third means which changes in response to actuation of said motor means.
Dependencies are inferred from the claim text.