Method and apparatus for driving stepping motor

Claim 2

A drive method of rotating a rotor of a stepping motor by sequentially switching/exciting a plurality of excitation windings of said stepping motor in a predetermined order, comprising the steps: (a) determining periodic velocity fluctuation characteristics of at least said stepping motor; (b) storing periodic velocity fluctuation data determined in step (a) in a memory device; and (c) exciting said excitation windings while causing time intervals of sequential switching/excitation of said excitation windings to fluctuate in correspondence with the periodic velocity fluctuation data stored in the memory device.

Claim 3

A method according to claim 1, wherein the step (a) comprises the step of obtaining periodic velocity fluctuation characteristics of a system including said stepping motor and a load connected thereto.

Claim 4

A method according to claim 1, wherein the step (c) comprises the step of determining excitation switching timings of said excitation windings o the basis of a pulse train, and causing a pulse rate of the pulse train to fluctuate so as to have a phase opposite to that of the periodic velocity fluctuation obtained in the step (a).

Claim 5

A method according to claim 3, wherein the step (c) comprises the step of determining a fluctuation amplitude of the pulse rate in correspondence with a fluctuation amplitude of the periodic velocity fluctuation.

Claim 6

A method according to claim 3, wherein the step (c) comprises the step of using a microstep excitation method in which a current to be applied to each of said excitation windings is increased/decreased stepwise.

Claim 7

A drive method of rotating a rotor of a stepping motor by sequentially switching/exciting a plurality of excitation windings of said stepping motor in a predetermined order, comprising the steps of: (a) obtaining periodic velocity fluctuation characteristics of at least said stepping motor; (b) obtaining current values of said excitation windings which reduce the periodic velocity fluctuation obtained in the step (a); (c) obtaining periodic velocity fluctuation characteristics of said stepping motor while said excitation windings are sequentially switched and excited by the current values obtained in the step (b); (d) storing periodic velocity fluctuation data obtained in step (c) in a memory device; and (e) exciting said excitation windings by using the current values obtained in the step (b) while causing time intervals in which said excitation windings are sequentially switched/excited to fluctuate in correspondence with the periodic velocity fluctuation data stored in the memory device.

Claim 8

A drive method of rotating a rotor of a stepping motor by sequentially switching/exciting a plurality of excitation windings of said stepping motor in a predetermined order, comprising the steps of: (a) obtaining periodic velocity fluctuation characteristics of at least said stepping motor; (b) obtaining current values of said excitation windings which reduce the periodic velocity fluctuation obtained in the step (a); (c) obtaining periodic velocity fluctuation characteristics of said stepping motor while said excitation windings are sequentially switched and excited by the current values obtained in the step (b); (d) storing periodic velocity fluctuation data obtained in step (c) in a memory device; and (e) exciting said excitation windings by using the current values obtained in the step (b) while causing time intervals in which said excitation windings are sequentially switched/excited to fluctuate in correspondence with the periodic velocity fluctuation data stored in the memory device.

Claim 9

A method according to claim 6, wherein the step (e) comprises the step of determining excitation switching timings of said excitation windings, and causing a pulse rate of the pulse train to fluctuate so as to have a phase opposite to that of the periodic velocity fluctuation obtained in the step (c).

Claim 10

A method according to claim 7, wherein the step (e) comprises the step of determining a fluctuation amplitude of the pulse rate in correspondence with a fluctuation amplitude of the periodic velocity fluctuation obtained in the step (c).

Claim 11

A method according to claim 6, wherein the step (e) comprises the step of using a microstep excitation method in which a current to be applied to each of said excitation windings is increased/decreased stepwise.

Claim 12

A drive apparatus for switching/exciting a plurality of excitation windings of a stepping motor in a predetermined order, comprising: a DC power source for supplying exciting currents to said plurality of excitation windings; switching means arranged between said DC power source and said plurality of excitation windings, said switching means including a plurality of switching elements; pulse generating means for generating a pulse train used as timing pulses for switching said plurality of excitation windings; means for receiving the pulse train generated by said pulse generating means and ON/OFF-controlling said switching elements of said switching means in a predetermined order; memory means for storing periodic velocity fluctuation data of at least said stepping motor; and means for reading out the velocity fluctuation data stored in said memory means, and causing a pulse rate of the timing pulses generated by said pulse generating means to fluctuate in correspondence with the velocity fluctuation data.

Claim 13

A drive apparatus for switching/exciting a plurality of excitation windings of a stepping motor in a predetermined order, comprising: a DC power source for supplying exciting currents to said plurality of excitation windings; switching means arranged between said DC power source and said plurality of excitation windings, said switching means including a plurality of switching elements; pulse generating means for generating a pulse train used as timing pulses for switching said plurality of excitation windings; means for receiving the pulse train generated by said pulse generating means and ON/OFF-controlling said switching elements of said switching means in a predetermined order; memory means for storing periodic velocity fluctuation data of at least said stepping motor; and means for reading out the velocity fluctuation data stored in said memory means, and causing a pulse rate of the timing pulses generated by said pulse generating means to fluctuate in correspondence with the velocity fluctuation data.

Claim 14

An apparatus according to claim 10, wherein said memory means stores periodic velocity fluctuation data of a system including said stepping motor and a load connected thereto.

Claim 15

An apparatus according to claim 10, wherein said means for causing the pulse rate to fluctuate causes the pulse rate of the timing pulses to have a phase opposite to that of velocity fluctuation obtained from the velocity fluctuation data stored in said memory means.

Claim 16

An apparatus according to claim 12, wherein said means for causing the pulse rate to fluctuate causes the pulse rate of the timing pulses to fluctuate in correspondence with amplitudes of velocity fluctuation obtained from the velocity fluctuation data stored in said memory means.

Claim 17

A drive apparatus for switching/exciting a plurality of excitation windings of a stepping motor in a predetermined order, comprising: a DC power source for supplying exciting currents to said plurality of excitation windings; switching means arranged between said DC power source and said plurality of excitation windings, said switching means including a plurality of switching elements; pulse generating means for generating a pulse train used as timing pulses for switching said plurality of excitation windings; means for receiving the pulse train generated by said pulse generating means and ON/OFF-controlling said switching elements of said switching means in a predetermined order; current adjusting means for adjusting currents flowing in said plurality of excitation windings so as to reduce periodic velocity fluctuation of at least said stepping motor; memory means for storing periodic velocity fluctuation data of said stepping motor which is obtained while the currents flowing in said plurality of excitation windings are adjusted by said current adjusting means; and means for reading out the velocity fluctuation data stored in said memory means, and causing a pulse rate of the timing pulses generated by said pulse generating means to fluctuate in correspondence with the readout velocity fluctuation data.

Claim 18

A drive apparatus for switching/exciting a plurality of excitation windings of a stepping motor in a predetermined order, comprising: a DC power source for supplying exciting currents to said plurality of excitation windings; switching means arranged between said DC power source and said plurality of excitation windings, said switching means including a plurality of switching elements; pulse generating means for generating a pulse train used as timing pulses for switching said plurality of excitation windings; means for receiving the pulse train generated by said pulse generating means and ON/OFF-controlling said switching elements of said switching means in a predetermined order; current adjusting means for adjusting currents flowing in said plurality of excitation windings so as to reduce periodic velocity fluctuation of at least said stepping motor; memory means for storing periodic velocity fluctuation data of said stepping motor which is obtained while the currents flowing in said plurality of excitation windings are adjusted by said current adjusting means; and means for reading out the velocity fluctuation data stored in said memory means, and causing a pulse rate of the timing pulses generated by said pulse generating means to fluctuate in correspondence with the readout velocity fluctuation data.

Claim 19

An apparatus according to claim 14, wherein said memory means stores periodic velocity fluctuation data of a system including said stepping motor and a load connected thereto.

Claim 20

An apparatus according to claim 14, wherein said means for causing the pulse rate to fluctuate causes the pulse rate of the timing pulses to have a phase opposite to that of velocity fluctuation obtained from the velocity fluctuation data stored in said memory means.

Claim 21

An apparatus according to claim 16, wherein said means for causing the pulse rate to fluctuate causes the pulse rate of the timing pulses to fluctuate in correspondence with amplitudes of velocity fluctuation obtained from the velocity fluctuation data stored in said memory means.

Claim 22

A drive apparatus for switching/exciting a plurality of excitation windings of a stepping motor in a predetermined order, comprising: a DC power source for supplying exciting currents to said plurality of excitation windings; switching means arranged between said DC power source and said plurality of excitation windings, said switching means including a plurality of switching elements; pulse generating means for generating a pulse train used as timing pulses for switching excitation of said plurality of excitation windings and increasing/decreasing levels of exciting currents of said plurality of excitation windings in a stepwise manner; means for receiving the pulse train generated by said pulse generating means, and switching/exciting said plurality of excitation windings by ON/OFF-controlling said switching elements of said switching means in a predetermined order; means for receiving the pulse train generated by said pulse generating means, and increasing/decreasing levels of exciting currents flowing in said plurality of excitation windings in a stepwise manner; current adjusting means for increasing/decreasing levels of exciting currents flowing in said plurality of excitation windings so as to reduce periodic velocity fluctuation of said stepping motor; memory means for storing periodic velocity fluctuation data of said stepping motor which is obtained while the currents flowing in said plurality of excitation windings are adjusted by said current adjusting means; and means for reading out the velocity fluctuation data stored in said memory means, and causing a pulse rate of the timing pulses generated by said pulse generating means to fluctuate in correspondence with the readout velocity fluctuation data.

Claim 23

A drive apparatus for switching/exciting a plurality of excitation windings of a stepping motor in a predetermined order, comprising: a DC power source for supplying exciting currents to said plurality of excitation windings; switching means arranged between said DC power source and said plurality of excitation windings, said switching means including a plurality of switching elements; pulse generating means for generating a pulse train used as timing pulses for switching excitation of said plurality of excitation windings and increasing/decreasing levels of exciting currents of said plurality of excitation windings in a stepwise manner; means for receiving the pulse train generated by said pulse generating means, and switching/exciting said plurality of excitation windings by ON/OFF-controlling said switching elements of said switching means in a predetermined order; means for receiving the pulse train generated by said pulse generating means, and increasing/decreasing levels of exciting currents flowing in said plurality of excitation windings in a stepwise manner; current adjusting means for increasing/decreasing levels of exciting currents flowing in said plurality of excitation windings so as to reduce periodic velocity fluctuation of said stepping motor; memory means for storing periodic velocity fluctuation data of said stepping motor which is obtained while the currents flowing in said plurality of excitation windings are adjusted by said current adjusting means; and means for reading out the velocity fluctuation data stored in said memory means, and causing a pulse rate of the timing pulses generated by said pulse generating means to fluctuate in correspondence with the readout velocity fluctuation data.

Claim 24

An apparatus according to claim 18, wherein said memory means stores periodic velocity fluctuation data of a system including said stepping motor and a load connected thereto.

Claim 25

An apparatus according to claim 18, wherein said means for causing the pulse rate to fluctuate causes the pulse rate of the timing pulses to have a phase opposite to that of velocity fluctuation obtained from the velocity fluctuation data stored in said memory means.

Claim 26

An apparatus according to claim 20, wherein said mean for causing the pulse rate to fluctuate causes the pulse rate of the timing pulses to fluctuate in correspondence with amplitude fluctuation of velocity fluctuation obtained from the velocity fluctuation data stored in said memory means.