Off-Road Surface Roughness Index for Stable Path Tracking

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Solution Overview

Problem

Off-road vehicles face challenges in maintaining accurate path tracking due to ground surface irregularities, leading to operator fatigue and uneven application of crop inputs, as existing automatic guidance systems struggle to account for varying soil conditions and hidden surface irregularities.

Innovation Solution

A method and system that estimate surface roughness by using motion data, pitch, and roll sensors to determine a surface roughness index, which is then used to adjust the ground speed of the vehicle, allowing for real-time adaptation to different terrain conditions and improving path tracking precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If automatic guidance system is used to guide vehicle to track path plan, then path tracking capability is improved, but vehicle still experiences unwanted deviations in heading or yaw due to ground surface irregularities

Engineering Contradiction:
Improvepath tracking accuracyVSAvoidheading stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system continuously monitors vehicle motion data, pitch, and roll to detect surface irregularities in real-time. This feedback loop allows the guidance system to identify deviations caused by ground conditions and adjust the path plan dynamically, improving both tracking accuracy and heading stability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system estimates surface roughness ahead of time by analyzing vehicle motion responses to ground irregularities. By detecting and characterizing surface conditions in advance, the system can proactively adjust guidance parameters before encountering significant deviations, maintaining more stable heading control

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If vehicle operates over ground with surface irregularities, then vehicle can traverse various terrain conditions, but operator fatigue increases due to increased vibrations in the cab

Engineering Contradiction:
Improveterrain traversal capabilityVSAvoidoperator fatigue
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system dynamically adjusts vehicle ground speed based on real-time surface roughness estimates. By slowing down on rough terrain and maintaining optimal speeds on smoother sections, the system reduces vibrations transmitted to the cab, decreasing operator fatigue while preserving the ability to traverse diverse terrain

Inventive Principle:
Principle #15Dynamics

3Productivity

If vehicle maintains constant ground speed, then operational efficiency is improved, but uneven application of crop inputs occurs due to surface irregularities causing path deviations

Engineering Contradiction:
Improveoperational efficiencyVSAvoidcrop input application uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system transitions from constant ground speed to dynamic speed adjustment based on surface roughness. By modulating vehicle speed in response to terrain conditions, the system compensates for path deviations caused by irregularities, ensuring uniform crop input application while minimizing impact on overall operational efficiency

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3878257B1Method and system for estimating surface roughness of ground for an off-road vehicle to control ground speed
Publication Date: 2023.09.20 DEERE & CO
  • EP3878257B1 patent drawingFigure 1A
  • EP3878257B1 patent drawingFigure 1B
  • EP3878257B1 patent drawingFigure 2A

AI summary

A method and system for estimating surface roughness of a ground for an off-road vehicle to control ground speed comprises detecting motion data of an off-road vehicle traversing a field or work site during a sampling interval. A pitch sensor is adapted to detect pitch data of the off-road vehicle for the sampling interval to obtain a pitch acceleration. A roll sensor is adapted to detect roll data of the off-road vehicle for the sampling interval to obtain a roll acceleration. An electronic data processor or surface roughness index module determines or estimates a surface roughness index based on the detected motion data, pitch data and roll data for the sampling interval. The surface roughness index can be displayed on the graphical display to a user or operator of the vehicle, or applied to control or execute a ground speed setting of the vehicle.