Vehicle Avoidance Trajectory Control for Low-Speed Steering Stability

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Solution Overview

Problem

Large turning angle changes during autonomous object avoidance in vehicles cause passenger discomfort due to excessive steering wheel movement.

Innovation Solution

A vehicle control method that determines vehicle speed reduction, detects lateral deviation, generates a target travel trajectory to suppress lateral deviation changes, and adjusts deceleration to avoid obstacles while maintaining speed, thereby reducing turning angle changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the vehicle autonomously avoids an object by generating a large turning angle change, then the avoidance effectiveness is improved, but the steering wheel moves largely causing passenger discomfort

Engineering Contradiction:
Improveavoidance effectivenessVSAvoidpassenger discomfort
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the target travel trajectory based on real-time vehicle speed. When vehicle speed is below a threshold, the trajectory generation is modified to suppress lateral deviation changes, thereby reducing steering angle changes and passenger discomfort while maintaining adequate avoidance capability at low speeds

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the trajectory generation parameters based on vehicle speed conditions. By detecting whether vehicle speed is below a threshold and adjusting the trajectory accordingly, the system reduces excessive steering movements at low speeds while preserving avoidance effectiveness when needed

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4398215B1Vehicle control method and vehicle control apparatus
Publication Date: 2025.11.19 NISSAN MOTOR CO LTD
  • EP4398215B1 patent drawingFigure 1~2B
  • EP4398215B1 patent drawingFigure 3
  • EP4398215B1 patent drawingFigure 4A~4C

AI summary

A vehicle control method causing a controller (16) to execute: vehicle speed determination processing (S2) of determining whether or not vehicle speed of an own vehicle is reduced to less than a predetermined speed threshold; lateral deviation detection processing (S10) of detecting lateral deviation of the own vehicle with respect to a lane center or a lane boundary line; target trajectory generation processing (S13) of, when determining that the vehicle speed is reduced to less than the speed threshold, generating a first target travel trajectory of the own vehicle in such a way as to suppress change in the lateral deviation at and after a vehicle speed reduction time point, the vehicle speed reduction time point being a time point at which the vehicle speed is reduced to less than the speed threshold; avoidance target detection processing (S1) of detecting an avoidance target to be avoided by the own vehicle; and avoidance processing (S14) of avoiding the avoidance target by, after the vehicle speed reduction time point, adjusting deceleration of the own vehicle while the own vehicle travels along the first target travel trajectory.