Steering Angle Sensor Standby Position Detection
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Solution Overview
Problem
Existing steering angle sensors fail to accurately determine the absolute angular position of a steering wheel when in standby or powered-down mode, limiting their functionality in driving dynamics control systems.
Innovation Solution
A steering angle sensor system comprising a multi-axis detector and a quadrature encoder detector, which includes a first gear connected to the steering wheel shaft and a second gear assembly with a split gear, allowing for the detection of steering wheel movement and direction even when the vehicle ignition is off, using a magnet and Hall-effect sensors to track the steering wheel's position and rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a multi-axis detector is used to measure steering wheel rotation, then measurement precision is improved, but power consumption increases when in standby mode
Solution Approach 1:
The patent implements periodic measurement cycles where the multi-axis detector operates in alternating active and standby modes. During active mode, full measurement functionality is available; during standby mode, the system transitions to a lower-power state. This periodic operation allows the system to maintain measurement precision when needed while significantly reducing power consumption during extended periods between steering inputs.
2Use of energy by moving object
If the sensor operates in powered-down mode to save energy, then power consumption is reduced, but the ability to detect steering wheel movement is lost
Solution Approach 1:
The system performs preliminary actions by continuously monitoring for steering wheel movement even in standby mode using a simplified detection mechanism. When movement is detected, the system proactively transitions to active mode before full measurement is required, ensuring no steering inputs are missed while maintaining low power consumption during normal standby operation.
Solution Approach 2:
The patent introduces an intermediary detection mechanism that operates between the fully-powered multi-axis detector and the completely powered-down state. This intermediary mode uses reduced-power sensors or simplified measurement techniques to detect steering wheel movement, serving as a mediator that maintains basic detection capability while consuming minimal power during standby operation.
3Device complexity
If a single detector is used, then device complexity is reduced, but the ability to function in both active and standby modes is compromised
Solution Approach 1:
The patent implements multi-functionality by designing a sensor system where the same physical detector can operate in multiple modes. The multi-axis detector is configured to perform full-steering-angle measurement during active mode and simplified movement detection during standby mode, eliminating the need for separate detection mechanisms for different operational states.
Solution Approach 2:
The system dynamically adjusts the operational characteristics of the detector based on the current mode. During active mode, the detector operates with full resolution and sampling rates for precise steering angle measurement. During standby mode, the same detector operates with reduced sampling rates or simplified measurement sequences, allowing the system to adapt its functionality to match power availability and operational requirements.
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 determination of the steering wheel's absolute angular position both when the vehicle is on and off, enhancing the functionality of driving dynamics control systems by providing a cost-effective and power-efficient solution.
Implementation Method 1
using a magnet and Hall-effect sensors to track the steering wheel's position and rotation
Data Source
AI summary
A steering angle sensor assembly 10 for determining absolute angular position of a steering wheel of a motor vehicle and includes a multi-axis detector 24 having an active operating mode and a standby operating mode and being adapted to measure speed and direction of rotation of the steering wheel. The steering angle sensor assembly 10 further includes at least one second detector 26 arranged to form a quadrature encoder to detect movement and direction of the steering wheel when the multi-axis detector 24 is in the standby or powered down operating mode.