Method and apparatus to automatically tune paper-feeding controller

• US 20060145646A1
• Filed: 12/30/2005
• Published: 07/06/2006
• Est. Priority Date: 12/30/2004
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Sung-ryul
• Application Number:
  US11/320,793
• Publication Number:
  US 20060145646A1
• Time in Patent Office: Days
• US Class Current: 318/538
• CPC Class Codes: B41J 13/103 for the sheet feeding section

Abstract

A method and apparatus to automatically tune a paper-feeding controller included in a paper-feeding system of a printer by eliminating effects of disturbance and thus accurately and automatically calculating gain of the paper-feeding controller. The method of automatically tuning a controller in a paper-feeding system of a printer using a DC motor includes acquiring input and output data of the paper-feeding system by conducting an open loop test, pre-filtering the input and output data to eliminate a drift offset from the acquired input and output data, identifying a system using the pre-filtered input and output data and inducing a system model and calculating a gain of the controller using the induced system model and controlling a velocity of the paper-feeding system according to the calculated gain. Accordingly, the method can minimize effects of disturbances present in the paper-feeding system of the printer, acquire a more accurate system model, and ultimately, obtain improved control performance.

Claims

1. A method of automatically tuning a controller in a paper-feeding system of a printer using a DC motor, the method comprising:

acquiring input and output data of the paper-feeding system by conducting an open loop test;

pre-filtering the input and output data to eliminate a drift offset from the acquired input and output data;

approximating the paper-feeding system using the pre-filtered input and output data to induce a system model; and

calculating a gain of the controller using the induced system model and controlling a velocity of the paper-feeding system according to the calculated gain.

2. The method of claim 1, wherein the acquiring of the input and output data comprises:

inputting a test signal that maintains a plus or minus sign of an output velocity unchanged to eliminate effects of load friction.

3. The method of claim 1, wherein the pre-filtering of the input and output data comprises:

filtering the input and output data to eliminate a drift offset using a predetermined curve fitting method to design a filter.

4. The method of claim 1, wherein the pre-filtering of the input and output data comprises:

eliminating torque ripples and ripples caused by machine vibrations by low pass filtering the input and output data.

5. The method of claim 1, wherein the approximating of the paper-feeding system comprises:

inducing the system model from the pre-filtered input and output data using a least square method.

6. The method of claim 1, wherein the calculating of the gain of the controller comprises:

calculating the gain of the controller by a pole placement method using the induced system model.

7. The method of claim 1, wherein the controller comprises a proportional, integral and derivative controller.

8. A method of automatically tuning a controller in a paper-feeding system of a printer, the method comprising:

inputting a test signal to the paper-feeding system and measuring the input test signal and an output velocity signal;

pre-filtering the measured input test signal and output velocity signal to remove disturbances therefrom;

modeling the paper-feeding system according to the pre-filtered input test signal and output velocity signal; and

calculating a gain of the controller according to the modeled paper-feeding system to control the velocity of the paper-feeding system of the printer.

9. The method of claim 8, wherein the inputting of the test signal comprises:

initializing a sampling interval and a frequency of the test signal; and

determining parameters of the test signal such that the output velocity signal is always greater than zero.

10. The method of claim 9, wherein the measuring of the input test signal and the output velocity signal comprises:

measuring and storing values of the input test signal and the output velocity signal according to the sampling interval.

11. The method of claim 8, wherein the pre-filtering of the measured input test signal and output velocity signal comprises:

filtering high frequency noise from the measured input test signal and output velocity signal using low pass filtering; and

filtering the measured input test signal and output velocity signal to eliminate a drift offset.

12. The method of claim 11, wherein the filtering of the measured input test signal and output velocity signal to eliminate a drift offset comprises:

curve fitting the measured input test signal and output velocity signal into linear functions, respectively; and

offsetting the measured input test signal and output velocity signal by values of he respective linear functions.

13. The method of claim 8, wherein the modeling of the paper-feeding system comprises:

applying a least square method to the pre-filtered input test signal and output velocity signal to estimate system parameters of the paper-feeding system.

14. The method of claim 13, wherein the calculating of the gain of the controller comprises:

applying a pole placement method to the estimated system parameters of the paper-feeding system to calculate the gain of the controller.

15. An apparatus to automatically tune a controller in a paper-feeding system of a printer using a DC motor, the apparatus comprising:

a data acquirer to acquire input and output data of the paper-feeding system by conducting an open loop test;

a pre-filter to eliminate a drift offset from the acquired input and output data;

a system model inducer to approximate the paper-feeding system using the pre-filtered input and output data to induce a system model; and

a gain calculator to calculate a gain of the controller using the induced system model and to control a velocity of the paper-feeding system according to the calculated gain.

16. The apparatus of claim 15, wherein the data acquirer inputs a test signal that maintains a plus or minus sign of an output velocity unchanged to eliminate effects of load friction.

17. The apparatus of claim 15, wherein the pre-filter comprises a drift filter to eliminate a drift offset using a curve filting method.

18. The apparatus of claim 15, wherein the pre-filter comprises a low pass filter to eliminate torque ripples and ripples caused by machine vibrations.

19. The apparatus of claim 15, wherein the system model inducer induces the system model from the acquired input and output data using a least square method.

20. The apparatus of claim 15, wherein the gain calculator calculates the gain of the controller by a pole placement method using the induced system model.

21. The apparatus of claim 15, wherein the controller comprises a proportional, integral and derivative controller.

22. An apparatus to automatically tune a controller in a paper-feeding system of a printer, the apparatus comprising:

an open loop testing unit to input a test signal to the paper-feeding system and to measure the input test signal and an output velocity signal of the paper-feeding unit;

a pre-filtering unit to pre-filter the measured input test signal and output velocity signal to eliminate disturbances therefrom; and

a calculating unit to estimate a model of the paper-feeding system according to the pre-filtered input test signal and output velocity signal and to calculate a gain of the controller according to the estimated model of the paper-feeding system to control a velocity of the paper-feeding system.

23. The apparatus of claim 22, wherein the open loop testing unit measures values of the input test signal and the output velocity signal at a predetermined sampling interval.

24. The apparatus of claim 22, wherein the input test signal comprises test signal parameters determined such that the output velocity signal is always greater than zero.

25. The apparatus of claim 22, wherein the pre-filtering unit comprises:

a low pass filter to eliminate high frequency noise from the measured input test signal and output velocity signal; and

a drift signal to eliminate a drift offset from the measured input test signal and output velocity signal.

26. The apparatus of claim 22, wherein the calculating unit estimates system parameters of the paper-feeding system by applying a least square method to the pre-filtered input test signal and output velocity signal, and calculates the gain of the controller by applying a pole placement method to the estimate system parameters.

27. A paper feeding system usable with a printing apparatus, comprising:

a DC motor to feed paper at a velocity;

a controller to control the velocity of the DC motor; and

a gain calculating unit to conduct and open loop test on the DC motor to obtain input and output values, to pre-filter the input and output values to remove disturbances therefrom, to model a system corresponding to the DC motor according to the pre-filtered input and output values, and to calculate a gain of the controller according to the modeled system.

28. A computer readable storage medium having executable codes to perform a method of automatically tuning a controller in a paper-feeding system of a printer using a DC motor, the method comprising:

acquiring input and output data of the paper-feeding system by conducting an open loop test;

pre-filtering the input and output data to eliminate a drift offset from the acquired input and output data;

approximating the paper-feeding system using the pre-filtered input and output data to induce a system model; and

calculating a gain of the controller using the induced system model and controlling a velocity of the paper-feeding system according to the calculated gain.