Rotation Angle Detection Device with Redundant Bridge Circuits
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Solution Overview
Problem
Conventional rotation angle detectors fail to accurately detect rotation angles due to mean value fixation abnormalities, where output signals persist at intermediate values, and are unable to calculate angles if operational amplifiers are short-circuited or sensor elements malfunction.
Innovation Solution
A rotation angle detection device comprising a circuit part with multiple sensor element groups, an output signal acquisition part, a rotation angle calculation part, and a mean value fixation check part, which uses dual bridge circuits and amplifiers to continuously calculate rotation angles even if one bridge circuit fails, and identifies mean value fixation abnormalities by analyzing output signals from sensor elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rotation angle detectors use single bridge circuit output signals, then the device complexity is reduced, but the reliability deteriorates when operational amplifiers are short-circuited or sensor elements malfunction
Solution Approach 1:
The detection device is divided into multiple independent sensor element groups (first and second groups) with separate bridge circuits. Each group can independently detect rotation angles, allowing the system to segment the detection function and continue operating even if one segment fails due to operational amplifier short-circuit or sensor element malfunction.
Solution Approach 2:
Different sensor element groups are configured with different bridge circuits and operational amplifiers, creating local independence in the system. This local quality allows specific parts of the system to fail without affecting the entire detection function, as each local group can independently provide rotation angle detection.
2Measurement precision
If conventional detectors use single output signal path, then the ease of operation is improved, but the measurement precision deteriorates when mean value fixation abnormality occurs
Solution Approach 1:
The system continuously monitors output signals from multiple sensor element groups and compares them to detect mean value fixation abnormalities. When an abnormality is detected in one group, the system switches to using signals from the other group, providing feedback-based protection that maintains measurement precision without requiring complex user intervention.
Solution Approach 2:
The system prepares multiple redundant signal paths in advance (first and second sensor element groups with separate bridge circuits) so that when mean value fixation abnormality occurs in one path, the alternative path is already ready to take over, cushioning against the impact of the abnormality and maintaining continuous accurate detection.
3Reliability
If conventional rotation angle detectors use single bridge circuit, then the manufacturing precision requirements are reduced, but the reliability deteriorates when one signal has abnormality
Solution Approach 1:
The detection system is segmented into multiple independent sensor element groups, each with its own bridge circuit and operational amplifier. This segmentation allows the system to manufacture and test each module independently, then combine them to create a highly reliable system where a single module failure does not compromise overall functionality.
Solution Approach 2:
When an abnormality is detected in one sensor element group or bridge circuit, the system automatically discards the faulty signal path and recovers by switching to the functional alternative path, ensuring continuous reliable operation without requiring manual intervention or complex repair procedures.
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 device effectively detects and mitigates mean value fixation abnormalities, ensuring accurate rotation angle calculation and continuous operation of electric power steering systems by using redundant signal paths and precise abnormality detection methods.
Implementation Method 1
The circuit part has plural sensor element groups for sensing a rotating magnetic field from a detection target, in which impedance of each of sensor elements in the sensor element groups changes according to a rotation angle of the detection target
Data Source
AI summary
A rotation angle detection device uses a control unit to acquire output signals Vx1, Vx2, Vy1, Vy2 that are from four half-bridges, from the four half-bridges. The control unit calculates a rotation angle θ of a detection target based on the acquired output signals Vx1, Vx2, Vy1, Vy2. The control unit checks whether a mean value fixation abnormality is caused to any one of the four output signals Vx1, Vx2, Vy1, Vy2, based on calculation values C1 or C4 that are derived/yielded from the four output signals Vx1, Vx2, Vy1, Vy2. The mean value fixation abnormality caused to the output signals Vx1, Vx2, Vy1, Vy2 that yielded the calculation values C1 and C4 is appropriately determined.