Warm-Start Trajectory Selection for Faster Autonomous Vehicle Planning

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Solution Overview

Problem

Conventional trajectory optimization methods for autonomous vehicles face challenges in finding a suitable initial guess, or 'warm start', due to dynamic scene changes, which affects the efficiency and speed of trajectory planning.

Innovation Solution

A method utilizing machine learning techniques, such as decision trees and feature mapping, to select a suitable warm start trajectory by evaluating candidate trajectories based on scene features and optimizing the trajectory planning process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional trajectory optimization methods are used without a suitable warm start, then the optimization problem can be formulated and solved, but the computational time increases and convergence speed decreases due to the difficulty of finding a good initial guess in dynamic scenes

Engineering Contradiction:
Improvetrajectory planning speedVSAvoidcomputational time
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The system pre-generates multiple candidate trajectories before the optimization process begins. These candidate trajectories serve as warm start initial guesses, eliminating the need to find an initial guess from scratch during real-time optimization. This preliminary action significantly reduces computational time while maintaining trajectory planning speed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary component that selects the best warm start candidate from multiple pre-generated trajectories. This intermediary selection process bridges the gap between having multiple candidates and finding the optimal initial guess, improving convergence speed without requiring exhaustive search of all possible initial conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple candidate trajectories are generated and evaluated to find the best warm start, then the quality of the initial guess improves, but the device complexity and computational resources required increase

Engineering Contradiction:
Improvewarm start qualityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of uniformly evaluating all candidate trajectories with the same computational effort, the system applies different evaluation strategies to different candidates. High-quality candidates receive more thorough evaluation while lower-quality ones are quickly filtered, optimizing the balance between warm start quality and system complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes parameters such as the number of candidate trajectories generated, the depth of evaluation for each candidate, and the selection criteria based on scene conditions and computational constraints. This dynamic parameter adjustment maintains high warm start quality while preventing excessive system complexity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If exhaustive evaluation of all candidate trajectories is performed to ensure the best warm start selection, then the reliability of trajectory optimization improves, but the productivity and real-time performance decrease

Engineering Contradiction:
Improveoptimization reliabilityVSAvoidreal-time planning efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs partial evaluation of candidate trajectories rather than exhaustive evaluation of all candidates. By evaluating only the most promising candidates in detail and using heuristic filtering for others, the system achieves sufficient optimization reliability without sacrificing real-time productivity.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent implements a multi-stage evaluation process where obviously inferior candidates are quickly skipped or rushed through with minimal evaluation. This allows the system to focus computational resources on promising candidates, maintaining reliability while improving real-time performance.

Inventive Principle:
Principle #21Skipping (Rushing through)

Data Source

PatentUS12371056B2Data-driven warm start selection for optimization-based trajectory planning
Publication Date: 2025.07.29 TOYOTA JIDOSHA KK
  • US12371056B2 patent drawing
  • US12371056B2 patent drawing
  • US12371056B2 patent drawing

AI summary

Systems and methods for trajectory planning for an autonomous vehicle, may include: computing features for each of the plurality of candidate trajectories; computing scores for the features of the candidate trajectories, wherein the scores are based on parameter values associated with their corresponding final trajectories; determining, based on the computed scores, a trajectory of the candidate trajectories to be used as a warm-start trajectory for trajectory optimization and applying the warm-start trajectory to develop a final trajectory for the vehicle; and autonomously operating the autonomous vehicle in accordance with the final trajectory.