Control apparatus using speed estimation for dc motor in image forming apparatus and method thereof
AssigneeSamsung Electronics Co., Ltd.
InventorTae Young Kim
Life of this patent
Estimating the term…
Abstract
A control apparatus for an image forming apparatus to control a DC motor at low speed using a low resolution encoder and a method thereof. If the encoder does not generate any pulses during a controlling period, the control apparatus estimates the speed of the DC motor using a formula model related to a plant in which an output speed of the direct current motor is varied according to an input voltage and a ripple model to estimate the speed of the direct current motor due to a load ripple caused by a gear driven by the direct current motor. The control apparatus avoids additional costs associated with high resolution encoders and strongly resists variation of load and has an excellent control performance.
Claims22
A control apparatus for controlling a direct current motor and comprising:
- a speed sensor to output pulses corresponding to a speed of the direct current motor;
- a speed estimating unit to determine a necessity to estimate the speed of the direct current motor, and to estimate the speed of the direct current motor according to the pulses output by the speed sensor when the speed estimation unit determines a need for the estimation of the speed of the direct current motor;
- and
- a motor driving unit to drive the direct current motor based on the estimated speed of the direct current motor estimated by the speed estimating unit.
A control apparatus for an image forming apparatus, the image forming apparatus comprising an image device to take a photograph of an image, a moving unit in which the image device is installed, and a direct current motor to move the moving unit, the control apparatus controlling the direct current motor and comprising:
- an encoder to output pulses corresponding to a speed of the direct current motor;
- a speed measuring unit to measure the speed and a position of the direct current motor according to the pulses of the encoder generated within controlling periods and to provide information about a previous speed and a previous position of the direct current motor required to estimate the speed of the direct current motor, when the speed and the position of the direct current motor are 0 (zero) as a result of the measurement according to the pulses;
- a controller to provide a control variable and a gain for the estimation of the speed of the direct current motor, based on the output pulses of the encoder;
- a speed estimating unit to apply the control variable provided by the controller and the previous speed, the previous position, and a previous voltage of the direct current motor provided by the speed measuring unit to a formula model to estimate the speed of the direct current motor;
- a speed controller to adjust the speed and the voltage of the direct current motor estimated by the speed estimating unit using the gain provided by the controller;
- and
- a motor driving unit to drive the direct current motor based on the motor driving voltage adjusted by the speed controller.
A method of controlling a direct current motor of an image forming apparatus, comprising an image device to take a photograph of an image, a moving unit in which the image device is installed, and the direct current motor to move the moving unit, the method comprising:
- measuring a speed and a position of the direct current motor according to pulses corresponding to the speed of the direct current motor;
- estimating the speed of the direct current motor according to a formula model when the pulses are not generated within controlling periods;
- outputting a motor driving voltage adjusted using a gain and a difference between the estimated speed of the direct current motor and a reference speed;
- outputting the motor driving voltage adjusted using the measured speed of the direct current motor and the reference speed when the pulses are generated within the controlling periods;
- and
- controlling the speed of the direct current motor based on the outputted motor driving voltage.
An image forming and/or obtaining apparatus comprising:
- an image forming/obtaining unit to print an image corresponding to image data onto a printable medium or to obtain image data corresponding to an image printed on the printable medium;
- and
- an image forming unit controller to control the image forming/obtaining unit, the image forming unit controller having a direct current motor to drive the image forming/obtaining unit, an encoder to output pulses corresponding to a speed of the direct current motor, a speed measuring unit to measure the speed and a position of the direct current motor based on the pulses and to provide information about a previous speed and a previous position of the direct current motor, a controller to provide a control variable and a gain for estimating the speed of the direct current controller, a speed estimating unit to estimate the speed of the direct current motor using a formula model, the formula model applying the control variable, the previous speed of the direct current motor, the previous position of the direct current motor, and a previous voltage of the direct current motor, a speed controller to adjust the estimated speed and voltage of the direct current motor using the gain provided by the controller, and a motor driving unit to drive the direct current motor based on the motor driving voltage adjusted by the speed controller.
A controller to control a direct current motor with stability and reliability, the controller comprising:
- a speed estimation unit to estimate the speed of the direct current motor using a formula model related to a plant in which an output speed of the direct current motor is varied according to an input voltage and a ripple model to estimate the speed of the direct current motor due to a load ripple caused by a gear driven by the direct current motor;
- and
- a motor driving unit to drive the direct current motor based on the estimated speed of the direct current motor estimated by the speed estimating unit.
Dependencies are inferred from the claim text.