Steering Instability Detection in Auto-Guided Vehicles

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Solution Overview

Problem

Automatic steering systems in agricultural and environmental management vehicles can become unstable due to incorrect configurations or external changes, leading to deviations from pre-planned paths, which can result in damaged crops, overplanting, and reduced yield.

Innovation Solution

A method and system for detecting steering wheel angle instability by measuring and analyzing the frequency spectrum of steering wheel angles, comparing them to a pre-defined threshold spectrum, and setting an instability flag when magnitudes exceed the threshold, allowing for adjustments in control gains or system responses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If automatic steering control is implemented to follow pre-planned paths, then path following precision is improved, but system stability deteriorates due to incorrect configurations or external changes

Engineering Contradiction:
Improvepath following precisionVSAvoidsystem stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system performs preliminary frequency analysis on steering wheel angle data to detect potential instabilities before they cause significant path deviations. By continuously monitoring the frequency spectrum and comparing it against threshold values, the system proactively identifies configuration errors or external changes that may compromise stability, allowing for preventive corrective action.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the frequency spectrum of steering wheel angles is continuously analyzed and compared against predefined thresholds. When the spectrum exceeds threshold values at any frequency, this indicates instability and triggers an alarm signal. This closed-loop feedback enables real-time monitoring and adjustment to maintain both path following precision and system stability.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If frequency analysis is performed continuously to detect instability, then detection precision is improved, but computational complexity increases

Engineering Contradiction:
Improveinstability detection precisionVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of performing a complete and continuous Fourier transform at every time step, the system applies frequency analysis to arrays of steering wheel angle values collected over predetermined time windows. This partial action approach analyzes frequency content at strategic intervals rather than continuously, achieving sufficient detection precision while significantly reducing computational burden and complexity.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3855876B1Steering instability detection
Publication Date: 2022.11.02 TRIMBLE INC
  • EP3855876B1 patent drawingFigure 1
  • EP3855876B1 patent drawingFigure 2
  • EP3855876B1 patent drawingFigure 3

AI summary

A method of detecting steering wheel angle instability in an auto-guided vehicle includes measuring a steering wheel angle at a plurality of time instances within a pre-determined time window to obtain an array of values of the steering wheel angle, performing a frequency analysis of the array of values of the steering wheel angle to obtain a frequency spectrum of the steering wheel angle, comparing the frequency spectrum of the steering wheel angle to a pre-defined threshold frequency spectrum to determine whether a magnitude of the frequency spectrum of the steering wheel angle at any frequency exceeds a magnitude of the threshold frequency spectrum, and upon determining that a magnitude of the frequency spectrum of the steering wheel angle at one or more frequencies exceeds a magnitude of the pre-defined threshold frequency spectrum, determining that a steering wheel angle instability is present.