Autonomous Vehicle Trajectory Optimization

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Solution Overview

Problem

Autonomous vehicles face challenges in smoothly transitioning between baseline and changed trajectories, leading to potential jerks or collisions due to inefficient path adjustments.

Innovation Solution

A method involving a computer system that defines vertices on the baseline trajectory, assigns cost functions based on distance and other criteria, and optimizes these vertices to determine a transitional trajectory that smoothly transitions from the baseline to the new trajectory, ensuring safe and efficient navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the vehicle directly switches from baseline trajectory to changed trajectory, then the response time is reduced, but the vehicle stability deteriorates causing jerks or collisions

Engineering Contradiction:
Improveresponse timeVSAvoidvehicle stability
Core Design Contradiction:
Loss of timeVSStability of the object's composition

Solution Approach 1:

The system performs preliminary action by pre-calculating and optimizing a transitional trajectory before the vehicle actually transitions. The computer system defines vertices on the baseline trajectory and pre-computes optimal transition paths to the changed trajectory, ensuring that when transition is needed, a smooth pre-planned path is already available. This eliminates abrupt changes while maintaining rapid response.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies dynamics by making the trajectory adaptable and adjustable during operation. The transitional trajectory is dynamically optimized based on real-time conditions, with vertices and path parameters that can be adjusted to balance speed and smoothness. This allows the vehicle to transition efficiently while maintaining stability through continuous adaptation of the path parameters.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the vehicle follows a smooth transitional trajectory, then the vehicle stability is maintained, but the time to reach the new trajectory increases

Engineering Contradiction:
Improvevehicle stabilityVSAvoidtransition time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The system utilizes parameter changes by optimizing vertices and trajectory parameters to achieve the best balance between smoothness and speed. The computer system adjusts parameters such as vertex positions, transition timing, and path curvature to minimize transition time while maintaining vehicle stability. This allows the transitional trajectory to be neither too abrupt nor too conservative.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If simple trajectory adjustment is used, then the computational complexity is reduced, but the trajectory optimization quality deteriorates

Engineering Contradiction:
Improvecomputational complexityVSAvoidtrajectory optimization quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The system applies segmentation by dividing the trajectory into discrete vertices along the baseline trajectory. Each vertex can be independently optimized with cost functions, allowing complex optimization to be broken down into manageable segments. This reduces computational complexity compared to optimizing the entire trajectory as a single continuous path, while still achieving high optimization quality through localized vertex adjustments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses parameter changes by defining cost functions that evaluate and optimize specific trajectory parameters such as distance to the changed trajectory, smoothness metrics, and safety constraints. These parameter-based cost functions enable systematic optimization of trajectory quality without requiring overly complex computational models, achieving good balance between computational efficiency and optimization quality.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9120485B1Methods and systems for smooth trajectory generation for a self-driving vehicle
Publication Date: 2015.09.01 WAYMO LLC
  • US9120485B1 patent drawing
  • US9120485B1 patent drawing
  • US9120485B1 patent drawing

AI summary

A vehicle configured to operate in an autonomous mode is provided. The vehicle is configured to follow a baseline trajectory. Changes to the baseline trajectory are received by a computer system associated with the vehicle. The computer system creates a function representing the current trajectory of the vehicle, as well as one or more functions defining any desired trajectory criteria, and generates an optimization problem from the functions, which, when solved, provide a new trajectory for the vehicle to follow that moves efficiently and smoothly toward the changed baseline trajectory.