Rotation-Angle Detection Device Cost Reduction via Drive Power Adjustment
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Solution Overview
Problem
Conventional rotation-angle detection devices for rotors in image processing apparatuses are expensive due to the need for complex configurations like ΔΣ modulation units, gain control loops, and storage units for accurate angle detection.
Innovation Solution
A rotation-angle detection device comprising plural rotation detectors, a rotation calculator, an amplitude detector, a drive-power adjuster, a corrector, and a rotation angle detector, which use sinusoidal detection signals varying with rotor angle and drive power to accurately detect the rotation angle without the need for expensive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ΔΣ modulation units, gain control loops, and storage units are used for rotation angle detection, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the complex ΔΣ modulation unit, gain control loop, and storage unit from the rotation angle detection device. Instead, it uses a simplified configuration with only a magnetic sensor and basic calculation circuits to achieve accurate rotation angle detection by directly processing the sinusoidal output signal from the magnetic sensor.
Solution Approach 2:
The patent replaces expensive, complex components with inexpensive, simple components. The detection device uses a basic magnetic sensor and simple calculation circuits instead of costly ΔΣ modulation units and gain control loops, achieving cost-effective rotation angle detection suitable for mass production in image processing apparatuses.
2Measurement precision
If conventional ΔΣ modulation units and gain control loops are implemented, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the expensive ΔΣ modulation unit and gain control loop from the detection device architecture. The simplified design uses only a magnetic sensor and basic calculation circuits, significantly reducing manufacturing cost while maintaining sufficient measurement precision for drive motor control in image processing apparatuses.
Solution Approach 2:
The patent adopts inexpensive components that can be mass-produced at low cost. By eliminating complex, expensive components and using only basic magnetic sensors and calculation circuits, the detection device becomes economically viable for widespread use in consumer image processing equipment.
3Device complexity
If simple detection structures are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent replaces complex mechanical/electronic signal processing mechanisms (ΔΣ modulation, gain control loops) with simple mathematical calculation circuits. The detection device uses basic trigonometric calculations on the magnetic sensor output to determine rotation angle, achieving accurate measurement with minimal hardware complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for accurate detection of rotor rotation angles with a cost-effective structure, reducing the complexity and expense of the detection system while maintaining high accuracy.
Implementation Method 1
A magnetic sensor, the output signal of which sinusoidally varies with the rotation angle of the rotor is arranged near an outer circumference of the rotor. A magnetic sensor such as a Hall element is used as the magnetic sensor.
Data Source
AI summary
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.