Reverse Trajectory Tracking Using Front-Wheel Angle Correction

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Solution Overview

Problem

Existing trajectory tracking methods primarily support forward travel environments and lack flexibility and broad application in reverse travel scenarios, particularly in autonomous parking systems which require specific arc-based reference trajectories.

Innovation Solution

A reverse trajectory tracking method and apparatus that determine an expected front wheel turning angle based on heading and lateral errors, and vehicle speed, allowing for real-time adjustment of actual wheel angles to accurately track trajectories in reverse travel, applicable to both autonomous and non-autonomous vehicles, with flexibility in reference trajectory shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing trajectory tracking methods are used for reverse travel, then the system can operate in forward travel environments, but it cannot support reverse travel scenarios

Engineering Contradiction:
Improvereverse travel scenario supportVSAvoidtrajectory tracking accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies inversion by transforming the forward-travel trajectory tracking method into a reverse-travel applicable method. This is achieved by reversing the trajectory points and inverting the steering angle calculations, allowing the system to track reverse trajectories accurately using the same underlying control architecture designed for forward motion.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes key parameters including the trajectory point sequence (reversed), steering angle direction (inverted), and control input signs to adapt the forward-travel control system for reverse-travel scenarios. These parameter transformations enable the existing control algorithm to function correctly in reverse motion without requiring complete system redesign.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If arc-based reference trajectories are used in parking systems, then reverse trajectory tracking can be achieved, but the method lacks flexibility and has narrow application range

Engineering Contradiction:
Improvereverse trajectory tracking capabilityVSAvoidreference trajectory shape flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal trajectory tracking method that works for both forward and reverse travel, and supports multiple trajectory shapes including but not limited to arc-based trajectories. The method can handle any reference trajectory by reversing points and adjusting steering angles, making it applicable to parking, narrow road passages, and other reverse travel scenarios with diverse path requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If existing forward travel trajectory tracking methods are applied to reverse travel, then the system structure remains simple, but the tracking accuracy and control precision deteriorate

Engineering Contradiction:
Improvesystem structure simplicityVSAvoidtrajectory tracking precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces dynamic adjustments to the control parameters based on travel direction. The system dynamically reverses trajectory points and inverts steering angle calculations when transitioning from forward to reverse travel, enabling accurate tracking adaptation without changing the fundamental system structure or adding complex hardware components.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3932781B1Reverse trajectory tracking method and apparatus, electronic device and storage medium
Publication Date: 2023.08.30 BEIJING BAIDU NETCOM SCI & TECH CO LTD
  • EP3932781B1 patent drawingFigure 1~2
  • EP3932781B1 patent drawingFigure 3
  • EP3932781B1 patent drawingFigure 4

AI summary

A reverse trajectory tracking method and apparatus, an electronic device and a storage medium are disclosed by the present application, which relates to a field of autonomous driving, and in particular to a field of autonomous parking and a field of trajectory tracking. The method includes: acquiring positioning information and reference trajectory of a vehicle; determining a heading error and a lateral error of the vehicle relative to a reference trajectory based on the positioning information and reference trajectory of the vehicle; determining an expected front wheel turning angle of the vehicle based on the heading error, the lateral error and a speed of the vehicle; adjusting an actual front wheel turning angle of the vehicle according to the expected front wheel turning angle of the vehicle.