Steer-by-Wire Rotation Angle Detection with Redundant Gears
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Solution Overview
Problem
Steer-by-wire systems face challenges in detecting rotation angles of steering wheels and tire steering amounts due to sensor element failures and power supply circuit failures, leading to unreliable steering control.
Innovation Solution
A rotation angle detection device with a rotating shaft, drive gear, and multiple driven gears with unique tooth counts, along with redundant sensors and power supply circuits, allowing for robust detection and control signal generation even with sensor or power supply failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors and power supply circuits are used for rotation angle detection, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent divides the rotation angle detection function into multiple independent sensor channels (first sensor, second sensor, third sensor) with different output waveforms, each detecting the same rotation angle through different driven gears. This segmentation allows the system to maintain detection capability even when individual sensors or power supply circuits fail, as other channels can compensate.
Solution Approach 2:
The patent implements redundant sensor elements and multiple power supply circuits before failures occur. The control device is pre-configured to handle sensor failures by switching to alternative sensor combinations or using backup power supply circuits, cushioning against the impact of failures and maintaining system reliability.
2Reliability
If redundant sensors and power supply circuits are implemented, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
Multiple sensors detect the same rotation angle parameter through different measurement paths (different driven gears and output waveforms), making each sensor universally capable of performing the primary detection function. This multi-functionality allows redundant sensors to serve both as primary detectors and as backups for other sensors, justifying their inclusion despite increased manufacturing cost.
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
Enhances the robustness against sensor and power supply failures, ensuring reliable steering control by generating rotation angle signals through multiple sensor combinations and power supply redundancy.
Implementation Method 1
a first sensor and a second sensor that are disposed to face the first magnet and detect an amount of rotation of the first driven gear
Implementation Method 2
a third sensor and a fourth sensor that are disposed to face the second magnet and detect an amount of rotation of the second driven gear
Implementation Method 3
a fifth sensor and a sixth sensor that are disposed to face the third magnet and detect an amount of rotation of the third driven gear
Data Source
AI summary
The present invention provides a rotation angle detection device that detects a steering state quantity of steer-by-wire. The rotation angle detection device includes a drive gear that rotates along with the rotation of a rotating shaft part, first through third driven gears that rotate in conjunction with the drive gear and have different numbers of teeth that are indivisible by each other, sensors that detect the amounts of rotation and are provided for the respective first through third driving gears, a rotation amount generating unit that generates the amount of rotation of the drive gear by combining the amounts of rotation of different driven gears, and power supply circuits each of which is provided for a combination of sensors that detect the amounts of rotation of different driven gears. This configuration makes it possible to improve robustness against failure of sensor elements and power supply circuits.