Stepping motor control method including varying the number of split sections in one step drive period of a stepping motor

• US 5,572,105 A
• Filed: 12/23/1994
• Issued: 11/05/1996
• Est. Priority Date: 12/27/1993
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hiramatsu, Soichi, Inoue, Hiroyuki, Kawazoe, Kenji, Ishikawa, Tetsuya, Nakamura, Hitoshi, Kida, Akira, Yamaguchi, Hideki, Nojima, Takashi, Kawakami, Hideaki, Miyakawa, Akira
• Primary Examiner(s): Cabeca, John W.
• Application Number:
  US08/363,012
• Time in Patent Office: 683 Days
• Field of Search: 318/696, 318/685, 318/560, 318/599, 318/603, 318/636, 318/606, 318/607, 318/608
• US Class Current: 318/696
• CPC Class Codes: H02P 8/22 Control of step size; Intermediate stepping, e.g. microstepping
• CPC Class Codes: H02P 8/32 Reducing overshoot or oscillation, e.g. damping

Abstract

A device for controlling the power supplied to windings of a stepping motor includes a pulse generator for splitting one step drive period of the motor into a plurality of sections, the number of sections and increasing or decreasing depending upon the drive frequency. The pulse generator, also sets the duty cycle of a pulse applied to the motor. The device also includes a stepping motor drive circuit for exciting each phase of the motor with a current determined by the duty cycle of pulse, and a duty changing device for changing the duty cycle for each of plural sections in one excitation phase of the stepping motor, wherein a current wave input into the motor can be maintained as a sinusoidal wave from low-speed rotation to high-speed rotation of the motor by changing the number of sections in excitation depending upon serial drive operations, thereby achieving motor control with less rotation inconsistencies and less noise.

Claims

1. A stepping motor control device comprising:

a stepping motor;

a drive circuit for driving said stepping motor, said drive circuit having a changeover circuit which changes an excitation phase of excitation current supplied to an excitation coil of said stepping motor whenever a step drive signal is applied thereto and having a switching circuit which controls the excitation current supplied to the excitation coil of said stepping motor in accordance with an applied pulse signal with a predetermined duty cycle;

a stepping signal generating portion for generating the step drive signal in accordance with a driving frequency for step-driving said stepping motor, said stepping signal generating portion applying the step drive signal to said changeover circuit of said drive circuit;

a control portion for splitting one step drive period of said stepping motor into a plurality of sections in accordance with the driving frequency of said stepping motor, said control portion varying the number of said split sections in accordance with the driving frequency of said stepping motor; and

a pulse signal generating portion for generating said pulse signal with a predetermined duty cycle for each of said split sections and for applying said pulse signal to said switching circuit of said drive circuit.

2. A device according to claim 1, wherein said control portion lowers the number of the sections obtained by splitting one step drive period of said stepping motor into a plurality of sections as the drive frequency of said stepping motor increases.

3. A device according to claim 1, wherein a split period when one step drive period of said stepping motor is split into a plurality of sections, is not more than 1 ms.

4. A control method of stepping motor according to claim 1, wherein said control portion sets the number of the sections obtained by splitting one step drive period of said stepping motor into a plurality of sections to be a first section number when the drive frequency of said stepping motor is less than a predetermined value, and said control portion sets the number of sections to be a second section number smaller than the first section number when the drive frequency is not less than the predetermined value.

5. A stepping motor control device having different drive modes, comprising:

a stepping motor;

a drive circuit for driving said stepping motor, said drive circuit having a changeover circuit which changes an excitation phase of excitation current supplied to an excitation coil of said stepping motor whenever a step drive signal is applied thereto and having a switching circuit which controls the excitation current supplied to the excitation coil of said stepping motor in accordance with a pulse signal with a predetermined duty cycle;

stepping signal generation means for generating the step drive signal in accordance with a driving frequency for step-driving said stepping motor, said stepping signal generation means applying the step drive signal to said changeover circuit of said drive circuit;

control means for causing said step drive signal generation means to generate the step drive signal having a driving frequency in accordance with the driving mode;

said control means having changing means for splitting one step drive period of the stepping motor into a plurality of sections in accordance with the driving frequency of said stepping motor, said changing means varying the number of said split sections in accordance with the driving mode of said stepping motor; and

pulse generating means for generating said pulse signal with a predetermined duty cycle for each of said split sections and for applying said pulse signal to said switching circuit of said drive circuit.

6. A stepping motor control device, comprising:

a stepping motor;

a drive circuit for driving said stepping motor, said drive circuit having a changeover circuit which changes an excitation phase of excitation current supplied to an excitation coil of said stepping motor whenever a step drive signal is applied thereto and having a switching circuit which controls the excitation current supplied to the excitation coil of said stepping motor in accordance with a pulse signal with a predetermined duty cycle;

stepping signal generating means for generating the step drive signal in accordance with a driving frequency for step-driving said stepping motor, said stepping signal generating means applying the step drive signal to said changeover circuit of said drive circuit;

changing means for splitting one step drive period of said stepping motor into a plurality of sections in accordance with the driving frequency of said stepping motor, said changing means varying the number of said split sections in accordance with the driving frequency of said stepping motor; and

pulse generation means for generating the pulse signal with the predetermined duty cycle in accordance with a preset cycle and for applying the pulse signal to said switching circuit of said drive circuit.