Rotation-angle detection device and method, and image processing apparatus

Patent metadata

Field	Value
Publication number	US-10075604-B2
Application number	US-201414315614-A
Country	US
Kind code	B2
Filing date	Jun 26, 2014
Priority date	Jul 3, 2013
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

According to an embodiment of the present invention, a rotation-angle detection device for detecting a rotation angle of a rotor includes: plural rotation detectors that output detection signals which vary with the rotation angle of the rotor; a rotation calculator that outputs a rotated vector by rotating a vector expressed by the detection signals; an amplitude detector that outputs an amplitude signal indicating amplitude of the detection signals by performing computation on at least one of signals expressing the rotated vector using a predetermined target amplitude; a drive-power adjuster that adjusts the amplitude of the detection signals by changing drive power applied to the rotation detectors according to the amplitude signal; a corrector that corrects the amplitude based on the amplitude signal and outputs a corrected detection signal; and a rotation angle detector that detects a rotation angle of the rotor based on the corrected detection signal.

First claim

What is claimed is:

1. A rotation-angle detection device for detecting a rotation angle of a rotor, the rotation-angle detection device comprising:
plural rotation detectors attached to the rotor and configured and arranged to output, from each of the plural rotation detectors, two or more detection signals as differential signal pairs, the detection signals varying sinusoidally with the rotation angle of the rotor and differing from each other in phase, and amplitude of the detection signals varying with magnitude of drive power applied to the rotation detectors;
a vector generator that generates two vector signals from the detection signals and outputs the generated signals;
a rotation calculator that receives the two vector signals from the vector generator and is configured to output two rotated vectors by performing rotation conversion of a vector expressed by the generated signals and outputs the rotated vectors;
a controller configured to receive at least one rotated vector from the rotation calculator and output a control signal by making a comparison between the at least one rotated vector and a target value;
a drive-power adjuster configured to receive the control signal from the controller and feedback the control signal to the rotation detectors in the form of a drive power signal that brings the amplitude of the detection signals to a target amplitude;
a corrector configured to correct the amplitude of the detection signals based on the control signal and output a corrected detection signal; and
a rotation angle detector configured to detect a rotation angle of the rotor based on the corrected detection signal.

2. The rotation-angle detection device according to claim 1 , wherein
the corrector includes
a level detector configured to compare the control signal against a predetermined threshold value and output a level signal indicating a magnitude relation between the control signal and the predetermined threshold value,
a gain generator configured to generate a gain, the gain being an amplification factor which depends on the level signal, and
an amplitude adjuster configured to adjust the amplitude of the detection signals by multiplying the detection signals by the gain generated by the gain generator.

3. The rotation-angle detection device according to claim 2 , wherein
the gain generated by the gain generator changes only to increase the amplification factor.

4. The rotation-angle detection device according to claim 1 , further comprising a difference calculator which calculates a difference between respective differential signal pairs output from the plural detectors.

5. The rotation-angle detection device according to claim 2 , wherein
the vector generator is configured to generate the vector expressed by the detection signals based on at least two of the differences calculated by the difference calculator and output the vector to the rotation calculator, and wherein
the vector generator includes the amplitude adjuster, the amplitude adjuster adjusting the amplitude of the detection signals by multiplying the detection signals by the gain when the vector generator generates the vector expressed by the detection signals.

6. The rotation-angle detection device according to claim 2 , wherein
the rotation calculator includes the amplitude adjuster.

7. An image processing apparatus comprising:
a rotor;
a drive mechanism for various types of image processing, the drive mechanism being to be driven by rotation of the rotor; and
a rotation-angle detector configured to detect a rotation angle of the rotor so that rotation of the rotor is controlled, wherein
the rotation-angle detector comprises;
plural rotation detectors attached to the rotor and configured and arranged to output, from each of the plural rotation detectors, two or more detection signals as differential signal pairs, the detection signals varying sinusoidally with the rotation angle of the rotor and differing from each other in phase, and amplitude of the detection signals varying with magnitude of drive power applied to the rotation detectors,
a vector generator that generates two vector signals from the detection signals and outputs the generated signals,
a rotation calculator that receives the two vector by performing rotation conversion of a vector expressed by the generated signals and outputs the rotated vectors,
a controller configured to receive at least one rotated vector from the rotation calculator and output a control signal by making a comparison between the at least one rotated vector and a target value,
a drive-power adjuster configured to receive the control signal from the controller and feedback the control signal to the rotation detectors in the form of a drive power signal that brings the amplitude of the detection signals to a target amplitude,
a corrector configured to correct the amplitude of the detection signals based on the control signal and output a corrected detection signal, and
a rotation angle detector configured to detect a rotation angle of the rotor based on the corrected detection signal.

8. A rotation-angle detection method for detecting a rotation angle of a rotor, the rotation-angle detection method comprising:
performing rotation calculation to output a rotated vector by rotating a vector expressed by two or more detection signals as differential signal pairs directly detected by and output from plural rotation detectors attached to the rotor and configured and arranged to output from each of the plural rotation detectors, the detection signals varying sinusoidally with the rotation angle of the rotor and differing from each other in phase, and amplitude of the detection signals varying with magnitude of drive power to the rotation detectors;
generating two vector signals from the detection signals and outputting the generated signals;
receiving the two vector signals and performing rotation conversion of a vector expressed by the generated signals and outputting the rotated vectors;
receiving at least one rotated vector and outputting a control signal by making a comparison between the at least one rotated vector and a target value;
receiving the control signal and feeding back the control signal in the form of a drive power signal that brings the amplitude of the detection signals to a target amplitude;
correcting the amplitude of the detection signals based on the control signal and outputting a corrected detection signal; and
detecting a rotation angle of the rotor based on the corrected detection signal.

9. The rotation-angle detection device according to claim 1 , wherein the corrector is further configured to compare the control signal to an upper limit value of the drive power signal and output a limit detection signal based on the comparison to a difference calculator between the plural rotation detectors and the rotation calculator.

10. The image processing apparatus according to claim 7 , wherein the corrector is further configured to compare the control signal to an upper limit value of the drive power signal and output a limit detection signal based on the comparison to a difference calculator between the plural rotation detectors and the rotation calculator.

11. The rotation-angle detection method according to claim 8 , further comprising comparing the control signal to an upper limit value of the drive power signal and outputting a limit detection signal based on the comparison.

12. The image processing apparatus according to claim 7 , wherein the image processing apparatus is a multi-function printer.

13. The rotation-angle detection device according to claim 1 , wherein the angle detec

Assignees

• Shimizu Fumihiro
• Ricoh Co Ltd

Inventors

• Shimizu Fumihiro

Classifications

• H04N1/00904 Primary

  Arrangements for supplying power to different circuits or for supplying power at different levels (H04N1/00896 takes precedence) · CPC title

• G01D5/145 Primary

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title

• G01D3/02

  with provision for altering or correcting the law of variation · CPC title