Rear Wheel Steering for Vehicle Trajectory Control
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Solution Overview
Problem
Existing vehicle trajectory control systems face challenges in actively preventing lane departure accidents due to involuntary deviations, as they often interfere with the driver's control or result in energy losses and discomfort, particularly when using front wheel actuators for steering or differential braking.
Innovation Solution
A vehicle trajectory control device that applies steering instructions to the rear wheels in real-time, using a stabilizing correction module, a supervision module for weighting coefficients, and an adjustment module to optimize steering setpoints, thereby avoiding interference with the driver and minimizing energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If electric power steering of front wheels is used for active lane keeping assistance, then the vehicle can be kept in lane through automatic steering control, but the driver feels the intervention at the wheel which is unpleasant and can cause misunderstanding
Solution Approach 1:
Instead of applying steering assistance to the front wheels (driver's side), the patent applies the corrective steering action to the rear wheels. This inverts the conventional approach, allowing automatic lane keeping without the driver feeling the intervention through the steering wheel, thus resolving the contradiction between automation and driver comfort.
2Reliability
If differential braking of wheels is used for trajectory control, then the vehicle can be corrected back to lane, but undesired braking occurs which is badly perceived by the driver and causes energy loss
Solution Approach 1:
Instead of using braking forces to correct lane deviation, the patent inverts the approach by using rear wheel steering to achieve the same trajectory correction. This avoids the energy loss and driver discomfort associated with unwanted braking while maintaining reliable lane keeping functionality.
3Reliability
If braking action is applied for lane keeping correction, then the vehicle trajectory can be adjusted, but the action is limited in time and occurrences reducing permanent aid capability
Solution Approach 1:
The patent replaces time-limited braking corrections with continuous rear wheel steering control. This inversion allows for permanent and sustained lane keeping aid without the temporal limitations inherent in braking-based systems, enabling long-duration corrective action.
Data Source
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AI summary
In view of controlling the course of a vehicle (1), the device comprises at least one input (43, 44) for receiving at least one quantity representative of one or more differences (ΨL, yL) between a reference course (30) and an actual course of the vehicle. Remarkably, the device (40) comprises at least one output (46) for producing, in real time, at least one steering set point (δr*) applicable to at least one rear wheel of the vehicle (1) in such a way as to maintain and/or bring said vehicle onto the reference course of same.