Vehicle Self-Location Calculation with Patterned Light and Periodic Reset

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Solution Overview

Problem

Existing vehicle self-location calculating methods fail to accurately determine the movement of a vehicle when the starting points for calculation are reset during unstable vehicle behavior.

Innovation Solution

A self-location calculating device that captures images of a road surface with a projected patterned light, calculates the vehicle's attitude angle, and updates its position and attitude by integrating changes in feature points on the images, resetting to initial values when the vehicle is in a stable state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the starting points for calculating self-location are continuously updated based on temporal changes in feature points, then the calculation can track vehicle movement, but errors accumulate and amplify during unstable vehicle behavior

Engineering Contradiction:
Improveself-location calculation accuracyVSAvoidcalculation stability during unstable behavior
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements periodic resetting of the starting points (initial position and initial attitude angle) to predetermined values when the vehicle is determined to be in a stable running state. This periodic reset prevents error accumulation during unstable behavior while maintaining accurate tracking during stable operation, directly resolving the contradiction between continuous tracking and error prevention

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses feedback from the running state determination unit to control when resetting occurs. The determination unit monitors vehicle running state and provides feedback to the self-location calculation unit, which then decides whether to reset starting points or continue incremental calculation. This feedback mechanism ensures resetting only occurs during stable behavior, maintaining both accuracy and reliability

Inventive Principle:
Principle #23Feedback

2Reliability

If the starting points are reset during unstable vehicle behavior, then error accumulation is prevented, but the calculation accuracy deteriorates due to frequent resets

Engineering Contradiction:
Improveerror preventionVSAvoidself-location calculation accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent makes the starting points dynamic rather than fixed, allowing them to be reset to predetermined values only when the vehicle is in a stable running state. During unstable behavior, the system continues incremental calculation without resetting. This dynamic adjustment of reset timing ensures errors are prevented without sacrificing accuracy during stable operation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of starting points (initial position and initial attitude angle) from fixed values to conditionally resettable values. By monitoring vehicle running state and changing the starting points only during stable behavior, the system prevents error accumulation while maintaining calculation accuracy during normal operation

Inventive Principle:
Principle #35Parameter changes

3Productivity

If feature points on the road surface are used to calculate attitude changes, then vehicle movement can be tracked, but the calculation becomes unreliable when vehicle behavior is unstable

Engineering Contradiction:
Improvemovement tracking capabilityVSAvoidcalculation reliability during unstable behavior
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The running state determination unit provides feedback about vehicle stability to the self-location calculation unit. When feedback indicates unstable behavior, the system switches to using predetermined initial values rather than continuously updating from feature point changes. This feedback-controlled switching maintains reliability during unstable behavior while preserving tracking capability during stable operation

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate calculation of vehicle self-location by stabilizing the starting points during stable vehicle behavior, minimizing errors and preventing their amplification.

Implementation Method 1

a light projector 11 projects a patterned light 32a onto a road surface 31

Methodology Applied
Scientific EffectLight projection: Light

Implementation Method 2

a camera 12 captures and thus obtains an image 38 of the road surface 31 around the vehicle 10

Methodology Applied
Scientific EffectImage capture: Photography

Data Source

PatentEP3113147B1Self-location calculating device and self-location calculating method
Publication Date: 2018.11.28 NISSAN MOTOR CO LTD
  • EP3113147B1 patent drawingFigure 1
  • EP3113147B1 patent drawingFigure 2
  • EP3113147B1 patent drawingFigure 3(a)~3(b)

AI summary

A self-location calculating device of the present invention projects a patterned light onto a road surface around a vehicle, as well as thereby captures and obtains an image of the road surface around the vehicle. Furthermore, the self-location calculating device detects a running condition of the vehicle. When it is determined that the vehicle is a running stable state, the self-location calculating device calculates a current position and a current attitude angle of the vehicle by adding an amount of change in an attitude to a predetermined initial attitude angle of the vehicle.