Road Gradient Segmentation for Stable Vehicle Shift Control

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Solution Overview

Problem

In vehicles traveling on roads with constant gradients, it is challenging to determine suitable control parameters when segments are long, leading to frequent changes that impair ride comfort, especially when segments are short.

Innovation Solution

A segment determination device that calculates a feature amount by summing areas of regions on either side of the road, setting one area as positive and the other as negative, and determines segments based on predetermined distances and altitude information to maintain constant control parameters for longer segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the segment length is increased to reduce the frequency of control parameter changes, then ride comfort is improved, but the accuracy of gradient representation deteriorates

Engineering Contradiction:
Improveride comfortVSAvoidgradient representation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent divides the road into multiple segments based on gradient characteristics, with each segment having a representative gradient value. By segmenting the road into appropriate lengths based on curvature and gradient variations, the system achieves both sufficient segment length for comfortable control parameter maintenance and adequate segmentation for accurate gradient representation. The segment length is dynamically determined rather than using a fixed long segment approach.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the segment length is decreased to improve gradient representation accuracy, then gradient accuracy is improved, but the frequency of control parameter changes increases

Engineering Contradiction:
Improvegradient representation accuracyVSAvoidride comfort
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent dynamically adjusts segment length based on road characteristics such as curvature radius and gradient variation. Rather than using a fixed short segment length, the system calculates optimal segment lengths that adapt to the specific road conditions, allowing longer segments in areas with stable gradients and shorter segments where gradient changes are frequent, thereby balancing accuracy and ride comfort.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If a fixed control parameter is maintained for the entire segment, then device complexity is reduced, but adaptability to actual road conditions deteriorates

Engineering Contradiction:
Improvecontrol parameter managementVSAvoidadaptability to road gradient
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent assigns different control parameters to different segments based on their specific gradient characteristics. Each segment has a representative gradient value that determines the appropriate control parameter, allowing the system to adapt to local road conditions while maintaining simplicity within each segment. This local differentiation enables adaptability without requiring complex continuous adjustment mechanisms.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3521122B1Segment determination device and segment determination method
Publication Date: 2024.02.21 ISUZU MOTORS LTD
  • EP3521122B1 patent drawingFigure 1
  • EP3521122B1 patent drawingFigure 2
  • EP3521122B1 patent drawingFigure 3

AI summary

A segment determination device (1) is provided with: an altitude information acquisition unit (41) that acquires altitude information for a plurality of points on a road on which a vehicle travels; a feature amount determination unit (42) that determines a feature amount indicating gradient information for the road on the basis of the altitude information for a plurality of points including a first point in front of the vehicle in the direction of travel thereof and a second point further frontward than the first point among the aforementioned plurality of points; and a segment determination unit (44) that, when the altitude information acquisition unit acquires altitude information for a separate plurality of points including a point further from the vehicle than each of the plurality of points used by the feature amount determination unit to determine the feature amount so that the feature amount determined by the feature amount determination unit becomes an amount outside of a predetermined range, determines a segment in which the first point serves as a starting point and whichever of two points adjacent to the second point is closer to the vehicle serves as an end point when said feature amount becomes an amount outside of the predetermined range.