US 5,838,132 AGranted

Stepper-motor control method

AssigneeMurata Kikai Kabushiki Kaisha

InventorMakoto Tanaka

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Abstract

A device for outputting a suitable rotation torque relative to a load torque or actual torque exerted on a stepper-motor when the stepper-motor is used as a drive of an image processing device. The output torque of the stepper-motor depends on a supply current to the stepper-motor. CPU determines a suitable supply current using a table in ROM so that the stepper-motor is able to rotate at an optimum rotation torque. To this end, CPU sends a particular signal to the motor driver so that an appropriate supply current is supplied to the excitation phases A/B of the stepper-motor. The CPU determines the load torque based on an integrated current fed to the stepper-motor during a particular period. The CPU calculates difference between the load torque and rotation torque and determines the signal to be applied to the motor driver based on the torque difference.

Claims1

Dependent claims

A control method for a stepper-motor, comprising:

(a) determining a present integrated value of a current supplied to the stepper motor;
(b) determining a present load torque applied to the stepper-motor from said present integrated value determined in step (a) using a first table which stores a relationship between plurality of load torques of the stepper-motor and a plurality of integrated values of current supplied to the stepper-motor;
(c) calculating a torque difference between a preset rotational torque of the stepper-motor and the present load torque determined in step (b);
(d) determining one of a feed current or a pulse speed from said torque difference calculated in step (c) using a second table which stores a relationship between a plurality of rotational torques of the stepper-motor and one of a plurality of feed currents of the stepper-motor or a plurality of pulse speeds of the stepper-motor;
and
(e) controlling an output torque in response to one of the feed current and the pulse speed determined in step (d).

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/954,027Filed 20 Oct 1997 · continuation
Priority: JP 7-05090010 Mar 1995
Granted: 17 Nov 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G05B 19/39
Characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement…:…
G05B 2219/41112
Servomotor, servo controller till figures: control parameter such as motor controlled by a torque signal
G05B 2219/41326
Servomotor, servo controller till figures: step motor
Y10S 388/906
Specific system operational feature: proportional-integral system