Trajectory Initialization for Autonomous Vehicle Planning

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Solution Overview

Problem

Conventional autonomous vehicle planning systems often over- or under-estimate the vehicle's state, leading to abrupt acceleration or deceleration, failure to stop completely, or other control issues that result in an unpleasant ride, unnecessary wear, and potential non-compliance with traffic rules.

Innovation Solution

The system employs a multi-layer planning approach with a decision planning system and a drive planning system operating at different frequencies to generate and refine vehicle trajectories, using sensor data to determine better initialization states and smooth out control inputs, ensuring a comfortable and safe ride.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional models are used to estimate vehicle state, then the planning system can generate control trajectories, but the model may over- or under-estimate the actual state leading to abrupt acceleration or deceleration

Engineering Contradiction:
Improveride comfortVSAvoidvehicle state estimation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system implements feedback by continuously comparing the actual vehicle state (from sensors) with the estimated state (from the model) and using this difference to correct trajectory initialization. The planning system receives feedback about estimation errors and adjusts subsequent trajectory generation to compensate for model inaccuracies, preventing abrupt control actions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary action by pre-initializing trajectories using the model's estimated state before executing control commands. This allows the system to prepare smooth transition paths in advance based on predicted vehicle state, ensuring that control inputs are gradual and comfortable rather than abrupt when the actual state is reached.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If conventional trajectory generation is used, then control trajectories can be produced, but abrupt acceleration or deceleration occurs resulting in unnecessary wear on the vehicle

Engineering Contradiction:
Improvetrajectory generation speedVSAvoidvehicle wear
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system applies dynamics by making the trajectory initialization adaptive rather than static. The initialization state is dynamically adjusted based on the difference between actual and estimated vehicle states, allowing the trajectory generation to smoothly adapt to real conditions. This dynamic adjustment prevents abrupt control commands that would cause vehicle wear while maintaining efficient trajectory generation.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If conventional models estimate vehicle state, then trajectories can be generated, but the vehicle may fail to comply with traffic rules and regulations

Engineering Contradiction:
Improvetrajectory planning flexibilityVSAvoidtraffic rule compliance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system uses feedback from actual vehicle state measurements to ensure reliable traffic rule compliance. By continuously monitoring the difference between estimated and actual states, the system can detect when model predictions would lead to non-compliance and adjust trajectories accordingly, ensuring that control actions always meet traffic requirements regardless of model estimation errors.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11392127B2Trajectory initialization
Publication Date: 2022.07.19 ZOOX INC
  • US11392127B2 patent drawing
  • US11392127B2 patent drawing
  • US11392127B2 patent drawing

AI summary

Trajectory determination for controlling a vehicle, such as an autonomous vehicle, is described. In an example, a vehicle system includes multiple planning systems for calculating trajectories. A first system may calculate first trajectories at a first frequency and the second system may calculate second trajectories at a second frequency and based on the first trajectories. The first and/or second trajectories may be initialized at states of the vehicle corresponding to a projection onto a previous-in-time respective first or second trajectory. The second trajectories may be control trajectories along which the vehicle is controlled.