Automated Lane Change Path Planning Using B-Spline Control Points
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Solution Overview
Problem
Conventional automated lane change systems in autonomous vehicles often result in rough or jerky maneuvers, particularly at higher speeds and on curving roadways, leading to undesirable noise, vibration, and harshness (NVH) due to the force required for steering.
Innovation Solution
An automated lane change control system that uses a steering system and a controller to determine a desired path defined by a B-spline based on end control points and intermediate control points, optimizing the yaw rate and vehicle speed to smooth the lane change process, and updates the path dynamically using camera images to ensure a smoother transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional automated lane change systems apply steering force to complete the lane change maneuver, then the lane change function is achieved, but the vehicle produces noise, vibration, and harshness (NVH) that is perceived as rough or jerky
Solution Approach 1:
The system dynamically adjusts the lane change maneuver based on real-time vehicle speed and roadway curvature conditions. The controller modifies the steering commands throughout the lane change process, applying less aggressive steering at higher speeds and on curving roadways, thereby reducing NVH while still completing the lane change maneuver successfully
Solution Approach 2:
The system changes the steering parameters (steering angle, rate of change) based on vehicle speed and roadway curvature. By adjusting these parameters dynamically, the system achieves smooth lane changes that minimize vibration and harshness while maintaining lane change functionality
2Speed
If the vehicle performs automated lane change at higher speeds, then the lane change efficiency is improved, but the steering force required increases causing rougher maneuvers and increased NVH
Solution Approach 1:
The controller continuously monitors vehicle speed and adjusts the steering commands accordingly. At higher speeds, the system applies more gradual and smoother steering inputs rather than aggressive commands, thereby maintaining lane change efficiency while reducing the harshness and vibration associated with high-speed maneuvers
3Loss of time
If the automated lane change follows a direct path between lanes, then the lane change time is reduced, but the steering requires higher force causing jerky movements
Solution Approach 1:
Instead of following a direct linear path, the system employs a curved trajectory for the lane change maneuver. This curved path allows the vehicle to transition between lanes more smoothly by distributing the steering requirements over a longer, gentler arc, thereby reducing peak steering forces and eliminating jerky movements while maintaining acceptable lane change time
Data Source
AI summary
Automated vehicle lane change systems and methods comprise determining a departing lane in which the vehicle is currently traveling and a merging lane in which the vehicle will be traveling after an automated lane change, determining a desired yaw rate of the vehicle based on a current speed of the vehicle, determining an end control point in each of a departing lane and a merging lane, determining a set of intermediate control points based on the end control points and the desired yaw rate, determining a basis spline (B-spline) defined by the end control points and the set of intermediate control points to obtain a desired path between the end control points, and commanding a steering system configured to control steering of the vehicle such that the vehicle follows the desired path.