Vehicle Wheel Ground Contact Loss Detection via Vertical Displacement

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Solution Overview

Problem

Existing methods for determining imminent ground contact loss in vehicle wheels are not robust enough, particularly in heavy-duty vehicles, and do not effectively redistribute torque to maintain vehicle stability and operation.

Innovation Solution

A method using a control unit to determine the actual relative vertical displacement of wheels and calculate a limit margin, comparing it to a predetermined threshold to assess the imminence of ground contact loss, and adjusting torque distribution through differentials to maintain wheel contact and vehicle stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing methods are used to determine ground contact loss, then the determination can be made, but the method is not robust enough for heavy-duty vehicles

Engineering Contradiction:
Improverobustness of ground contact loss determinationVSAvoidprecision of ground contact loss assessment
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the parameter used for determination from lateral acceleration (prior art) to relative vertical displacement of the wheel. This parameter change provides a more direct and robust measurement of ground contact status, particularly for heavy-duty vehicles where vertical displacement is more indicative of imminent ground contact loss than lateral acceleration.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If torque redistribution is implemented to prevent ground contact loss, then vehicle stability is maintained, but the system complexity increases

Engineering Contradiction:
Improvevehicle stabilityVSAvoidcomplexity of torque distribution system
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the control unit continuously monitors relative vertical displacement and automatically adjusts torque distribution through the differential when ground contact loss is detected. This closed-loop feedback system maintains vehicle stability by redistributing torque to wheels with maintained ground contact, while the automation reduces the need for complex manual intervention systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control unit and differential system serve multiple functions: they detect ground contact loss, determine imminence of loss, redistribute torque during propulsion, and manage torque during braking. This multi-functionality consolidates what could be separate complex systems into a unified control architecture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3157771B1A method for determining whether or not ground contact loss is imminent for a wheel of a vehicle.
Publication Date: 2019.08.07 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP3157771B1 patent drawingFigure 1
  • EP3157771B1 patent drawingFigure 2
  • EP3157771B1 patent drawingFigure 3

AI summary

The present disclosure relates to a method for determining whether or not ground contact loss is imminent for a wheel (20, 22, 24) of a vehicle (10), said vehicle (10) comprising a vehicle body (12) having a vertical extension in a vertical direction (V), said wheel (20, 22, 24) being allowed to be subjected to a relative vertical displacement, in said vertical direction (V), in relation to said vehicle body (12), said vehicle (10) further being such that a maximum value of a vertical displacement of said wheel (20, 22, 24) relative to said vehicle body (12) is limited to a relative vertical displacement limit (Vl), said method comprising: - determining an actual relative vertical displacement (dv) of the wheel relative to said vehicle body (12), - determining a limit margin (lm) as the difference between said actual relative vertical displacement (dv) and said relative vertical position limit (vl) and - determining that ground contact loss is imminent for a wheel (20, 22, 24) if said limit margin (lm) is within a predetermined vertical threshold range.