Rotation Angle Detection Using Asymmetric Field Lengths
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Solution Overview
Problem
Existing rotation angle detecting devices suffer from inaccurate detection due to foreign material adhesion or scratches on the rotating part, which deforms detection signal waveforms and affects specific control processes.
Innovation Solution
A rotation angle detecting device with a first detector and a second detector, where the second detector's detection field is shorter and out of phase with the first detector's, allowing for the detection of foreign material or scratches without waveform deformation, thereby maintaining detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single detector is used to detect rotation angle, then the device structure is simple, but detection accuracy deteriorates when foreign material adheres to or scratches the rotating part
Solution Approach 1:
The detection system is segmented into multiple detectors (first detector and second detector) with different detection field lengths. The first detector has a longer detection field and is susceptible to foreign material interference, while the second detector has a shorter detection field and remains unaffected. This segmentation allows the system to maintain detection accuracy by using the unaffected detector's signals when foreign material is present.
Solution Approach 2:
The invention changes the parameter of detection field length between the first and second detectors. By setting different lengths for the detection fields, the detectors respond differently to foreign material interference. The second detector's shorter detection field parameter ensures it remains unaffected by foreign material, while the first detector's longer field provides complementary detection data.
2Reliability
If the detection field length is increased to improve signal strength, then detection sensitivity improves, but susceptibility to foreign material interference increases
Solution Approach 1:
The detection system is divided into detectors with different field lengths to segment the response to foreign material. The first detector with longer field provides strong signal when clean, while the second detector with shorter field maintains signal strength without foreign material susceptibility, creating a segmented response strategy.
Solution Approach 2:
The detection fields are designed with asymmetric lengths where the second detector's field is deliberately made shorter than the first detector's field. This asymmetric design creates different interference characteristics, allowing the system to identify and compensate for foreign material effects by comparing the asymmetric responses.
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
Enables accurate detection of foreign material or scratches on the rotating part, preventing deterioration in rotation angle detection and ensuring reliable specific control processes.
Implementation Method 1
a first detector arranged to oppose the detected portion and configured to detect change of a physical quantity caused by rotation of the rotating part, inside a first detection field over the detected portion
Implementation Method 2
a second detector arranged to oppose the detected portion and configured to detect change of the physical quantity caused by rotation of the rotating part, inside a second detection field located over the detected portion
Data Source
AI summary
A rotation angle detecting device includes: a rotating part rotating integrally with the rotating shaft and including a detected portion; an A-phase detector detecting change of a physical quantity caused by rotation of the rotating part, inside a first detection field over the detected portion and outputting an A-phase signal; and a B-phase detector detecting change of the physical quantity caused by rotation of the rotating part, inside a second detection field located over the detected portion and outputting a B-phase signal that is out of phase with the A-phase signal. The second detection field is shorter than the first detection field with respect to the direction perpendicular to the rotating direction of the rotating part.