Lane Change Trajectory Evaluation for Safe Gap Selection
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Solution Overview
Problem
Current advanced driver assistance systems (ADAS) lack an effective method for evaluating inter-vehicle traffic gaps and time instances to perform lane change maneuvers, primarily focusing on lateral planning and neglecting longitudinal planning, which is crucial for safe and efficient lane changes.
Innovation Solution
A method and system that evaluate inter-vehicle traffic gaps and time instances by determining feasible motion trajectories, considering physical and design constraints, and predicting vehicle states over a prediction horizon, while accounting for safety critical events like unexpected braking maneuvers, to select the most appropriate gap and time for a lane change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lateral planning is prioritized for lane change maneuvers, then the lane change execution is simplified, but longitudinal safety and collision avoidance are compromised
Solution Approach 1:
The patent combines lateral planning and longitudinal planning into a unified lane change maneuver system. The trajectory generator simultaneously determines lateral position (lane change path) and longitudinal position (speed and distance control), ensuring both ease of execution and collision avoidance through integrated planning rather than separate operations
Solution Approach 2:
The patent transitions from two-dimensional lateral planning to three-dimensional trajectory planning by adding the longitudinal dimension (speed and distance over time). This enables the system to evaluate safe gaps in both lateral and longitudinal dimensions simultaneously, resolving the contradiction between simplified execution and safety
2Device complexity
If a fixed inter-vehicle gap threshold is used for lane change decisions, then the decision-making process is simplified, but adaptability to varying traffic conditions is reduced
Solution Approach 1:
The patent implements dynamic gap evaluation where the safe gap threshold is not fixed but adapts based on relative velocities of surrounding vehicles, ego vehicle acceleration capabilities, and traffic density. The trajectory generator continuously adjusts the evaluation criteria based on real-time traffic conditions, providing versatility without excessive complexity
Solution Approach 2:
The system changes the parameters used for gap evaluation dynamically - using relative velocity, acceleration rates, and time-to-collision metrics instead of a fixed distance threshold. This allows the same evaluation system to adapt to varying traffic conditions by adjusting which parameters are most relevant in each situation
3Reliability
If multiple trajectories are evaluated for lane change maneuvers, then safety and optimality are improved, but computational complexity and processing time increase
Solution Approach 1:
The patent evaluates multiple trajectories but applies pruning strategies to focus computation on the most promising options. Rather than exhaustively evaluating all possible trajectories, the system identifies and evaluates a subset of critical trajectories that offer the best safety and efficiency balance, reducing processing time while maintaining reliability
Solution Approach 2:
The system performs preliminary evaluation of trajectory feasibility before detailed optimization. By pre-filtering trajectories based on basic safety criteria and geometric constraints, the system reduces the number of trajectories requiring full evaluation, thus maintaining safety while reducing computational time
Data Source
Figure 1~3
AI summary
The present disclosure relates to a method and a system for evaluating inter-vehicle traffic gaps and time instances to perform a lane change manoeuvre. The method comprises a) determining a set of trajectories which respectively constitutes an approximation of the feasible motion of the ego vehicle, b) evaluating the set of trajectories on the available inter-vehicle traffic gaps and time instances to perform the lane change manoeuvre over a prediction horizon, to select a subset of feasible inter-vehicle traffic gaps and time instances to perform the lane change manoeuvre and to establish a corresponding set of lane change trajectories, c) evaluating the set of lane change trajectories on the set of feasible inter-vehicle traffic gaps and time instances from a safety critical perspective, and d) selecting a preferred lane change trajectory, with corresponding inter-vehicle traffic gap and time instance, to perform the lane change manoeuvre. The disclosure further relates to an automated lane change system, an advanced driver assistance system and a vehicle comprising such a system.