Apparatus and method for controlling an electric motor
First Claim
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1. An apparatus for controlling an electric motor provided to drive a movable object such that a detected actual amount of motion of a movable portion of said electric motor or said movable object coincides with a target amount of motion, comprising:
- a pulse generator operable to periodically generate signal pulses such that each of the signal pulses is generated each time said movable portion of said electric motor or said movable object is driven by a predetermined amount;
an edge counter operable to count the number of at least one of a rising edge and a falling edge of said signal pulses generated by said pulse generator,a control-condition changing device including (a) a target-motion-amount setter operable to set said target amount of motion of said movable portion or said movable object, (b) a resolution selector operable to select one of different manners of counting said signal pulses by said edge counter, for thereby selecting a degree of a resolution of detection of said actual amount of motion, depending upon said target amount of motion set by said target-motion-amount setter, and (c) a target-count calculator operable to calculate a target number of the edges of said signal pulses which corresponds to said target amount set by said target-motion-amount setter, on the basis of said degree of the resolution of detection selected by said resolution selector, anda feedback motor controller comparing the number of the edges of said signal pulses counted by said edge counter with said target number of the edges calculated by said target-count calculator, and performing a feedback control of said electric motor for coincidence of said number of the edges of said signal pulses counted by said edge counter with said target number.
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Abstract
An apparatus for controlling an electric motor provided to drive a movable object such that a detected actual amount of motion of a movable portion of the electric motor or the movable object coincides with a target amount, comprising:
- a control-condition changing device operable to change at least one of (a) a resolution of detection of the actual amount of motion and (b) a voltage to be applied to the electric motor, depending upon the target amount; and
- a feedback motor controller operable to control the electric motor by application of the voltage, on the basis of the actual amount of motion detected with the resolution of detection and the target amount, such that the detected actual amount of motion coincides with the target amount. Also disclosed is a motor control method wherein the resolution of detection of the actual amount of motion and/or the voltage of the motor is/are changed depending upon the target amount of motion.
30 Citations
21 Claims
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1. An apparatus for controlling an electric motor provided to drive a movable object such that a detected actual amount of motion of a movable portion of said electric motor or said movable object coincides with a target amount of motion, comprising:
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a pulse generator operable to periodically generate signal pulses such that each of the signal pulses is generated each time said movable portion of said electric motor or said movable object is driven by a predetermined amount; an edge counter operable to count the number of at least one of a rising edge and a falling edge of said signal pulses generated by said pulse generator, a control-condition changing device including (a) a target-motion-amount setter operable to set said target amount of motion of said movable portion or said movable object, (b) a resolution selector operable to select one of different manners of counting said signal pulses by said edge counter, for thereby selecting a degree of a resolution of detection of said actual amount of motion, depending upon said target amount of motion set by said target-motion-amount setter, and (c) a target-count calculator operable to calculate a target number of the edges of said signal pulses which corresponds to said target amount set by said target-motion-amount setter, on the basis of said degree of the resolution of detection selected by said resolution selector, and a feedback motor controller comparing the number of the edges of said signal pulses counted by said edge counter with said target number of the edges calculated by said target-count calculator, and performing a feedback control of said electric motor for coincidence of said number of the edges of said signal pulses counted by said edge counter with said target number. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for controlling an electric motor provided to drive a movable object such that a detected actual amount of motion of a movable portion of said electric motor or said movable object coincides with a target amount of motion, comprising:
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an actual-motion-amount detector operable to detect said actual amount of motion of said movable portion of said electric motor or said movable object, a control-condition changing device including (a) a target-motion-amount setter operable to set said target amount of motion of said movable portion of said electric motor or said movable object, and (b) a voltage setter operable to set a voltage of an electric power source to be applied to said electric motor, such that said voltage is changed depending upon said target amount of motion set by said target-motion-amount setter; a feedback motor controller including a pulse-width-modulation controller which is operable to control, by pulse-width-modulation, an electric current supplied from said electric power source with said voltage set by said voltage setter such that said actual amount of motion detected by said actual-motion-amount detector coincides with said target amount of motion set by said target-motion-amount setter; said voltage setter setting said voltage of said electric power source to be applied to said electric motor such that said voltage is lower when said target amount of motion is relatively small than when said target amount of motion is relatively large; and wherein said voltage set is determined by said target amount of motion corresponding to a target feed distance in a memory. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An apparatus for controlling an electric motor provided to drive a movable object such that a detected actual amount of motion of a movable portion of said electric motor or said movable object coincides with a target amount of motion, comprising:
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an actual-motion-amount detector including (i) a pulse generator operable to periodically generate signal pulses such that each of the signal pulses is generated each time said movable portion of the electric motor or said movable object is driven by a predetermined amount, and (ii) an edge counter operable to count the number of at least one of a rising edge and a falling edge of said signal pulses generated by said pulse generator; a target-motion-amount setter operable to set said target amount of motion of said movable portion or said movable object; a resolution selector operable to select one of different manners of counting said signal pulse by said edge counter, for thereby selecting a degree of said resolution of detection of said actual amount of motion, depending upon said target amount of motion set by said target-motion-amount setter; a target-count calculator operable to calculate, on the basis of said degree of the resolution of detection selected by said resolution selector, a target number of the edges of said signal pulses counted by said edge counter, the target number corresponding to said target amount set by said target-motion-amount setter; a voltage setter operable to set a voltage of an electric power source to be applied to said electric motor, such that said voltage is changed depending upon said actual amount of motion set by said target-motion-amount setter; and a feedback motor controller which compares the number of the edges of said signal pulses counted by said edge counter, with said target number of the edges calculated by said target-count calculator, and performs a feedback control, by pulse-width-modulation, of a current supplied from said electric power source to said electric motor with said voltage, for coincidence of said number of the edges of said signal pulses counted by said edge counter with said target number.
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14. A method of controlling an electric motor provided to drive a movable object such that a detected actual amount of motion of a movable portion of said electric motor or said movable object coincides with a target amount of motion, comprising steps of:
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setting said target amount of motion of said movable portion or said movable object; selecting a degree of said resolution of detection of said actual amount of motion, depending upon the set target amount of motion; calculating a target number of at least one of a rising edge and a falling edge of signal pulses which are periodically generated such that each of the signal pulses is generated each time said movable portion of the electric motor or said movable object is driven by a predetermined amount, by a manner corresponding to the selected degree of the resolution of detection, the calculated number corresponding to the set target amount of motion; counting the number of the at least one of the rising and falling edges of the signal pulses by said manner; and feedback-controlling said electric motor by comparing the counted number of the edges of the signal pulses with the calculated target number of the edges, and performing a feedback control of said electric motor, for coincidence of said number of the edges of said signal pulses counted by said edge counter with said target number. - View Dependent Claims (15, 16, 17)
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18. A method of controlling an electric motor provided to drive a movable object such that a detected actual amount of motion of a movable portion of said electric motor or said movable object coincides with a target amount of motion, comprising steps of:
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changing a voltage of an electric power source to be applied to said electric motor, depending upon said target amount of motion, wherein said target amount of motion corresponds to a target feed distance in a memory; controlling, by pulse-width-modulation, a current supplied from said electric power source to said electric motor with said voltage changed in said step of changing said voltage of said electric power source, on the basis of said actual amount of motion detected, such that said detected actual amount of motion coincides with said target amount of motion; and said step of changing said voltage of said electric power source comprising changing said voltage such that said voltage is lower when said target amount of motion is relatively small than when said target amount of motion is relatively large. - View Dependent Claims (19, 20)
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21. A method of controlling an electric motor provided to drive a movable object such that a detected actual amount of motion of a movable portion of said electric motor or said movable object coincides with a target amount of motion, comprising steps of:
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setting said target amount of motion of said movable portion or said movable object; selecting a degree of said resolution of detection of said actual amount of motion, depending upon the set target amount of motion; calculating a target number of at least one of a rising edge and a falling edge of signal pulses which are periodically generated such that each of the signal pulses is generated each time said movable portion of the electric motor or said movable object is driven by a predetermined amount, by a manner corresponding to the selected degree of the resolution of detection, the calculated number corresponding to the set target amount of motion; counting the number of the at least one of the rising and falling edges of the signal pulses by said manner; changing a voltage of an electric power source to be applied to said electric motor, depending upon said target amount of motion; and feedback-controlling said electric motor by comparing the counted number of the edges of the signal pulses with the calculated target number of the edges, and performing a feedback control, by pulse-width-modulation, of a current supplied from said electric power source to said electric motor with said voltage, for coincidence of said number of the edges of said signal pulses counted by said edge counter with said target number.
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Specification