Rotation Angle Detector Short Circuit Detection
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Solution Overview
Problem
Conventional rotation angle detectors fail to accurately detect the rotation angle of a steering wheel due to short circuits between output terminals caused by conductive foreign matter, leading to erroneous signal recognition and detection.
Innovation Solution
The rotation angle detector incorporates anisotropic magnetoresistive elements with Wheatstone bridges and an amplifier that differentially amplifies signals, and a controller that connects output terminals to ground to detect short circuits, allowing for accurate detection of the rotation angle by distinguishing between normal and short-circuited signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rotation angle detectors are used, then the structure is simple and manufacturing is easy, but short circuits between output terminals occur due to conductive foreign matter leading to erroneous detection
Solution Approach 1:
The patent applies preliminary action by performing short circuit detection before normal rotation angle detection. The controller connects the output terminal to ground through a switching element to actively check for short circuits between output terminals. This preliminary detection prevents erroneous angle measurement by identifying short circuit conditions before they affect the detection results.
Solution Approach 2:
The patent introduces an intermediary switching element that connects the output terminal to ground during short circuit detection. This switching element acts as a mediator to create a test circuit configuration that allows the controller to detect short circuits without interfering with the normal detection operation. The switching element enables the system to transition between detection modes without permanent structural changes.
2Reliability
If output terminals are continuously monitored for short circuits, then detection accuracy improves, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by performing short circuit detection only at specific moments when the rotator is stationary, rather than continuously monitoring during all operation. The controller switches to ground connection mode periodically to check for short circuits, then returns to normal detection mode. This periodic approach maintains detection reliability while significantly reducing energy consumption compared to continuous monitoring.
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
This solution enables the accurate detection of the rotation angle of the steering wheel by effectively identifying and preventing short circuits between output terminals, thereby ensuring precise angle measurement without errors.
Implementation Method 1
AMR element 37 and AMR element 38... anisotropic magnetoresistive element (hereinafter, AMR element) 37 and AMR element 38 on its surface facing magnet 34 and magnet 35
Implementation Method 2
first Wheatstone bridge 41 and second Wheatstone bridge 42 each of which consists of four magnetoresistive elements 39 connected in a substantially rectangular shape
Implementation Method 3
amplifier 43 on wiring board 36... Amplifier 43 differentially amplifies these sine-wave and cosine-wave signals
Implementation Method 4
first and second detecting rotators 32 and 33 have magnet 34 and magnet 35, respectively, in their centers
Data Source
AI summary
A rotation angle detector includes a rotator, a detecting rotator, a magnet, an anisotropic magnetoresistive element, an amplifier, and a controller. The controller connects an output terminal of the anisotropic magnetoresistive element to the ground so as to detect a short circuit between adjacent output terminals based on the difference in output voltage from the amplifier. When there is no short circuit, the controller releases the connection from the output terminal to the ground, and detects the rotation angle of the rotator from the output signal that is differentially amplified by the amplifier based on the output signal of the anisotropic magnetoresistive element.