Steering Wheel Angle Validation Using Torque-Based Estimation
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Solution Overview
Problem
Steer-by-wire systems lack redundancy in steering angle sensors, leading to potential loss of directional stability and safety when one sensor fails, necessitating real-time detection and validation of steering wheel angle.
Innovation Solution
Implement a vehicle control system with a road wheel angle sensor, steering feedback motor, processor, and steering controller to estimate and validate steering wheel angle using a Kalman filter, and perform dynamic backup steering control and torque vector steering control in case of sensor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant steering angle sensors are implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a torque sensor as an intermediary measurement device that indirectly detects steering wheel angle through torque measurements. This intermediary approach allows the system to obtain steering angle information without requiring additional traditional angle sensors, thereby improving reliability while avoiding the complexity increase that would result from adding more sensors.
Solution Approach 2:
The patent replaces the mechanical sensor-based steering angle detection system with an electronic torque measurement system. By substituting mechanical angle sensors with electronic torque sensors and signal processing algorithms, the system achieves redundancy in steering angle detection without physically adding more sensors, thus improving reliability while maintaining system complexity at acceptable levels.
2Device complexity
If steering angle sensor redundancy is reduced, then device complexity is lowered, but reliability deteriorates
Solution Approach 1:
The torque sensor serves as an intermediary that provides redundant steering angle information without requiring additional traditional angle sensors. This intermediary measurement approach enables the system to maintain reliability through redundancy while avoiding the complexity increase that would result from adding more conventional sensors.
Solution Approach 2:
By replacing mechanical angle sensors with electronic torque measurement and signal processing, the system achieves sensor redundancy without physically duplicating sensors. This substitution allows the system to maintain low device complexity while improving reliability through computational redundancy.
3Reliability
If real-time steering angle validation is implemented, then reliability is improved, but processing time increases
Solution Approach 1:
The system performs preliminary validation of steering angle data continuously in the background, preparing and verifying multiple data points before they are needed for critical steering control. This preliminary action allows the validation process to be completed in advance, reducing the processing time impact when real-time steering commands are executed.
Solution Approach 2:
The patent implements feedback mechanisms that continuously monitor and validate steering angle measurements against expected physical constraints and historical data. By using feedback loops to verify data integrity in real-time, the system ensures reliability without requiring excessive processing time, as the validation is performed efficiently through constraint-based checking rather than exhaustive computation.
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
Ensures continued vehicle stability and safety by accurately estimating and validating steering angles even in the event of sensor failures, enabling robust control through dynamic backup and torque vector steering.
Implementation Method 1
a steering feedback motor configured to rotate a steering wheel in response to the road wheel angle and to generate a steering torque value in response to a physical rotation of the steering wheel by a vehicle driver
Implementation Method 2
the steering torque value is determined using a Kalman filter in response to a requested motor command, a torque sensor output, and an input noise
Data Source
AI summary
A vehicle steering control system including a road wheel angle sensor for detecting a road wheel angle, a steering feedback motor for rotating a steering wheel in response to the road wheel angle and for generating a steering torque value in response to a physical rotation of the steering wheel by a vehicle driver, a processor for receiving the road wheel angle and the steering torque value, for estimating a steering wheel angle in response to the steering torque value and for generating a validated steering angle in response to a difference between the road wheel angle and the steering wheel angle being less than a threshold value, and a steering controller for controlling the steering of a vehicle in response to the validated steering angle.