Rear Wheel Steering Midpoint Detection Using Intermediary Parameters
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Solution Overview
Problem
Conventional rear wheel steering vehicles face increased costs and safety hazards due to the need for multiple sensors and immediate disabling of rear wheel steering when a sensor error occurs, leading to instability and potential accidents.
Innovation Solution
A method that recognizes abnormal sensor conditions, determines if the vehicle is traveling straight by calculating speed, steering angular velocity, torque, and lane curvature, and switches to front wheel steering to maintain stability without additional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors are mounted to ensure reliable rear wheel steering detection, then system reliability improves, but device complexity and cost increase
Solution Approach 1:
The patent uses vehicle speed, steering angular velocity, steering column torque, and lane curvature as intermediary parameters to indirectly determine rear wheel steering midpoint position, replacing the need for additional stroke detection sensors. These existing sensors serve as mediators to achieve the same functional goal without increasing sensor quantity.
Solution Approach 2:
The system uses existing vehicle sensors (speed sensor, steering angle sensor, torque sensor, camera) to self-determine the rear wheel steering midpoint position without requiring external or additional dedicated sensors. The vehicle's own operational parameters are utilized to solve the detection problem.
2Reliability
If rear wheel steering function is immediately disabled when sensor error occurs, then safety is improved, but steering stability deteriorates due to heterogeneous sense
Solution Approach 1:
When the stroke sensor fails, the system uses intermediary parameters (vehicle speed, steering angular velocity, torque, lane curvature) to calculate and determine the rear wheel steering midpoint position, allowing the system to maintain stable operation without immediate function disablement.
Solution Approach 2:
The system performs preliminary determination of the rear wheel steering midpoint position using alternative parameters before the sensor failure becomes critical, enabling smooth transition and maintaining steering stability without abrupt function disabling.
3Device complexity
If rear wheel steering is controlled using existing sensors without additional devices, then device complexity is reduced, but measurement precision of stroke position deteriorates
Solution Approach 1:
The patent employs multiple intermediary parameters (vehicle speed, steering angular velocity, steering column torque, lane curvature) that collectively provide sufficient precision for determining rear wheel steering midpoint position, compensating for the lack of dedicated stroke sensors through multi-parameter fusion.
Solution Approach 2:
Existing vehicle sensors are made multi-functional by using them not only for their primary purposes but also for determining rear wheel steering midpoint position, achieving universal utilization of existing devices to maintain measurement precision without adding dedicated components.
4Ease of operation
If conventional methods are used to handle sensor errors, then ease of operation is maintained, but cost increases due to multiple sensors
Solution Approach 1:
The vehicle's existing sensor system serves itself to determine rear wheel steering midpoint position and handle sensor failures, eliminating the need for additional sensors while maintaining operational simplicity through automated calculation and mode switching.
Solution Approach 2:
Existing sensors are designed to perform multiple functions including their primary roles and rear wheel steering midpoint determination, reducing the total quantity of sensors needed while keeping the system easy to operate through integrated control logic.
Data Source
AI summary
Provided is a method for controlling rear wheel steering provided for a vehicle. The method includes: recognizing an abnormal condition of a sensor; calculating a speed of a vehicle; calculating a steering angular velocity of the vehicle; calculating torque of a steering column of the vehicle; determining a curvature of a lane along which the vehicle is traveling; and determining a rear wheel steering angle of the vehicle based on the speed of the vehicle, the steering angular velocity, the torque of the steering column, and the curvature of the lane.