Steering Wheel Motion Sensor Using Hall-Effect Detection
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Solution Overview
Problem
Conventional GPS-based vehicle guidance systems in agricultural and off-road vehicles face limitations in accurately detecting steering wheel movement for manual override and turn signal cancellation due to costly and inaccurate hydraulic sensing methods, which are further compromised by hydraulic seal leakage and limited magnetic pole accuracy.
Innovation Solution
A single steering wheel movement detection apparatus using a magnetic ring with at least 36 poles and hall-effect sensors to provide simultaneous movement and direction detection, eliminating mechanical and hydraulic interfaces, and integrating with electronic control systems for enhanced accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic sensing methods are used to detect steering wheel movement for GPS manual override, then the system can detect steering input, but the cost increases and accuracy is limited due to hydraulic seal leakage and temperature-dependent operation
Solution Approach 1:
The patent replaces the hydraulic sensing system with an electromagnetic sensing system using a magnetic ring and Hall effect sensors. This substitution eliminates the mechanical and hydraulic interfaces that caused seal leakage and temperature-dependent operation, providing reliable and precise detection of steering wheel movement and direction across all operating conditions
Solution Approach 2:
The patent introduces a magnetic ring as an intermediary element that couples the steering wheel to the Hall effect sensors without direct mechanical contact. This magnetic field mediator allows accurate detection of steering wheel position and direction while eliminating the need for hydraulic seals and mechanical linkages that were prone to leakage and wear
2Area of stationary object
If a single sensor housing is used to detect both steering wheel movement and direction, then spatial requirements are reduced, but the sensor must simultaneously detect multiple parameters which increases complexity
Solution Approach 1:
The patent designs a single sensor housing that performs multiple functions: detecting steering wheel movement magnitude, detecting steering direction, and providing inputs for both GPS manual override and turn signal self-cancellation systems. The Hall effect sensors generate signals that are processed to extract multiple parameters, making the sensor housing universal and multi-functional
Solution Approach 2:
The patent segments the sensor functions into distinct signal processing paths within the single housing. The Hall effect sensors generate raw signals that are separately processed to determine steering wheel position, movement direction, and movement magnitude. This segmentation allows multiple detection functions to coexist in one housing without interference
3Device complexity
If conventional reed switches and magnetic ring with limited poles are used for turn signal cancellation, then the system is simple, but accuracy is limited due to the limited number of magnetic poles
Solution Approach 1:
The patent changes the parameter of magnetic pole quantity from a limited number to at least 36 poles on the magnetic ring. This parameter change significantly increases the resolution and accuracy of steering wheel position detection for turn signal self-cancellation, while the electronic processing of Hall effect sensor signals maintains system simplicity
4Reliability
If hydraulic sensing is used for GPS manual override detection, then the system can function, but hydraulic seal leakage can allow slow steering wheel movement to go undetected
Solution Approach 1:
The patent replaces the hydraulic sensing system with an electromagnetic sensing system using a magnetic ring and Hall effect sensors. This substitution eliminates the mechanical and hydraulic interfaces that caused seal leakage and temperature-dependent operation, providing reliable and precise detection of steering wheel movement and direction across all operating conditions
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 solution enables precise detection of steering wheel movement and direction, reducing spurious signals, and providing a cost-effective, durable, and easy-to-use sensing apparatus that can initiate proper system responses and self-cancel turn signals, improving navigation and control functions.
Implementation Method 1
at least two hall-effect sensors fixed in a stationary position adjacent to the magnetic ring generate signals of fluctuating value as the magnetic poles pass
Data Source
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AI summary
A steering wheel movement sensing apparatus (20) for an agricultural vehicle (5) comprising a magnetic ring configured to fit around the steering column (13) such that it turns in unison with the steering wheel (12). The minimum number of magnetic poles (21) on the ring is not defined, but a ring having at least 36 poles enables the movement sensor to detect steering wheel movement of 10 degrees. At least two hall-effect sensors (23, 24) fixed in a stationary position adjacent to the magnetic ring generate signals of fluctuating value as the magnetic poles (21) pass enabling wheel movement and the extent of wheel movement to be derived. By specifically adjusting the position of the hall-effect sensors (23, 24) in relation to each other, the resultant output signals can also be used to determine the direction of movement of the steering wheel (12). Outputs from the sensing apparatus (20) can be used to disengage an automated vehicle guidance system (100) upon detection of steering wheel movement and to provide input to a self-cancelling turn signal system (50).