Vehicle Trajectory Correction via Multi-Criteria Gain Optimization
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Solution Overview
Problem
Existing lane keeping assistance systems for vehicles face challenges in maintaining dynamic response and passenger comfort due to limitations in tire saturation and curvature of the road, and do not effectively account for the vehicle's dynamic trajectory during correction, leading to suboptimal steering angles and lateral speeds.
Innovation Solution
A method for correcting a vehicle's trajectory that involves measuring lateral deviation and relative heading angle using a camera, calculating a correction gain through multi-criteria optimization to minimize lateral displacement, steering angle, and lateral speed, while considering constraints such as maximum steering angle and bounded lateral displacement and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If differential braking is used for lane departure avoidance, then the vehicle can be kept in its lane, but the action is limited by tire saturation and cannot provide continuous lane following
Solution Approach 1:
The patent changes the control parameter from braking force to steering angle. The active steering system adjusts the steering angle of the front wheels to correct lateral deviation, enabling continuous lane following without being limited by tire saturation effects that constrain braking-based approaches.
2Reliability
If active steering control is applied to correct lateral deviation, then the vehicle trajectory can be adjusted, but the dynamic response may be insufficient when speed variation or curvature is significant
Solution Approach 1:
The control gain is made dynamic rather than fixed. It is calculated in real-time based on current vehicle state parameters including lateral deviation, heading angle, and their derivatives. This adaptive gain adjustment enables the system to respond appropriately to varying dynamic conditions such as different speeds and curvatures.
3Loss of time
If large correction gains are used to reduce lateral deviation quickly, then the response time is reduced, but the steering angle and lateral speed may exceed acceptable limits affecting passenger comfort
Solution Approach 1:
The control gain is dynamically adjusted based on the current lateral deviation and its rate of change. When deviation is large, higher gains are used for faster correction; when deviation is small or the vehicle is already moving quickly laterally, lower gains are applied to ensure passenger comfort and avoid excessive steering angles.
4Stability of the object's composition
If the control system considers multiple constraints (maximum steering angle, bounded lateral displacement, maximum lateral speed), then the correction remains stable and comfortable, but the control law becomes more complex
Solution Approach 1:
Rather than using complex model predictive control or multiple nested control loops, the patent employs a relatively simple proportional-derivative control law where the gain is dynamically adjusted based on current state parameters. This approach achieves stable and comfortable correction while maintaining control law simplicity through adaptive parameter adjustment rather than structural complexity.
Data Source
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AI summary
The invention relates to a method for correcting the direction of travel of a motor vehicle, comprising a measurement step in which, from a vehicle-mounted camera, the lateral distance (YL) between the vehicle and a marking stripe on the ground is measured, a measurement step in which the relative heading angle (ΨL) corresponding to the angle between the longitudinal axis of the vehicle and a line on the traffic lane is measured, and a calculation step (10) in which a correction gain is calculated in accordance with the measured lateral distance and relative heading angle, and a control variable (u) that acts upon the steering angle of the front steered wheels is generated from the calculated correction gain. The correction gain calculation includes a multi-criterion optimization step in which the minimum value for each of the following criteria is ascertained during the correction of the direction of travel: the lateral movement in the traffic lane, the steering angle applied to the wheels, and the lateral speed of the vehicle.