Microstepping of an unipolar stepping motor

DETAILED DESCRIPTION It is a principal advantage of the preferred embodiment of the microstepping of an unipolar stepping motor to increase the resolution of the output of the motor.
It is yet a further advantage of the preferred embodiment to utilize an unipolar stepping motor having bifilar windings.
Another advantage of the preferred embodiment is to control the acceleration and deceleration of the stepper motor preventing motor overshoot at the desired position of the motor.
A method for controlling a unipolar stepping motor having a two phase winding and an output shaft connected to a driven member operable to be rotated to a desired position comprises the steps of coupling a first position sensor to the driven member for generating a signal indicating its present position.
A second signal is generated representing the desired position of the driven member.
The difference between the desired position and the present position of the driven member is calculated.
The magnitude of this difference generates a stepping rate for the motor.
A look-up table contains a plurality of values which respond to the size of the electrical step of the motor.
The values generate a signal indicating the angular rotation of the motor and then supply power to each winding of the motor for rotating the driven member to the desired position.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.