Single-Turn Steering Angle Sensor Absolute Position Determination
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Solution Overview
Problem
Existing vehicle control systems require reliable steering wheel angle data soon after vehicle power-up, which is typically achieved using expensive multi-turn absolute sensors, while there is a need for a cost-effective solution using single-turn sensors.
Innovation Solution
A method that senses steering wheel angle from a single-turn sensor, stores plausible positions, calculates expected outputs from vehicle sensors, and outputs a single absolute steering wheel angle by comparing sensed and calculated values, incorporating vehicle stability checks and offset calculations to eliminate invalid options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-turn absolute steering wheel angle sensor is used to obtain reliable steering wheel angle data quickly after key-on, then the reliability and measurement precision are improved, but the device cost increases significantly
Solution Approach 1:
The solution segments the determination process into multiple stages: initial plausible position generation, sensor output comparison, and iterative elimination. This allows a single-turn sensor to achieve multi-turn sensor reliability by processing data through structured segments rather than requiring a single expensive sensor component
Solution Approach 2:
The control system acts as an intermediary that processes and interprets data from the single-turn sensor alongside other vehicle sensors (yaw rate, lateral acceleration). This intermediary processing layer compensates for the single-turn sensor's limitation, achieving reliable absolute angle determination without the expensive multi-turn sensor
2Ease of manufacture
If a single-turn steering wheel angle sensor is used to reduce cost, then the device cost decreases, but the ability to determine absolute steering wheel angle quickly after key-on deteriorates
Solution Approach 1:
The system performs preliminary actions by pre-calculating plausible absolute steering wheel angle positions based on single-turn sensor data and vehicle dynamics models before final determination. This preliminary structuring of possible solutions enables rapid convergence to the correct angle, reducing the time loss after key-on
Solution Approach 2:
The control system continuously compares expected sensor outputs with actual measurements and uses this feedback to eliminate implausible positions. This iterative feedback process rapidly converges on the correct absolute steering wheel angle, compensating for the single-turn sensor's limitations and reducing determination time
3Measurement precision
If multiple plausible absolute steering wheel angle positions are considered to ensure accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The system dynamically adjusts the set of plausible positions based on vehicle operating conditions, sensor data quality, and confidence levels. Rather than statically processing all possible positions, the algorithm adapts its search space and processing depth, maintaining measurement precision while managing computational complexity through dynamic decision-making
Data Source
AI summary
A method and algorithm for determining a steering wheel angle of a vehicle steering mechanism upon power up of a vehicle using a single-turn steering wheel angle sensor by eliminating plausible steering wheel angles until one and only one steering wheel angle possibility remains.