Agricultural Vehicle Wheel Brake Control via Torque Synchronization

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Solution Overview

Problem

Agricultural vehicles, particularly tractors, face challenges in maintaining driving comfort and reducing wheel brake wear due to uneven braking forces caused by changes in torque and force transmission during gear shifts and all-wheel driving mode changes, leading to increased braking distances and wear.

Innovation Solution

A control device regulates wheel brake force based on signals from speed sensors and torque changes detected in the drive train, synchronizing braking force with torque changes to prevent wheel locking and reduce interventions, thereby optimizing braking within the static friction limit and minimizing wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the braking force is individually regulated based on speed sensor signals only, then wheel locking is prevented, but driving comfort deteriorates due to unnecessary brake interventions during gear shifts and mode changes

Engineering Contradiction:
Improvewheel locking preventionVSAvoiddriving comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control device detects gear shift operations and all-wheel driving mode changes in advance, and temporarily reduces or suspends brake force regulation during these transitions. This preliminary detection and preventive action avoids unnecessary brake interventions that would degrade driving comfort, while still maintaining wheel locking prevention capability when actually needed.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the brake force is continuously regulated to maintain optimal deceleration, then braking performance is improved, but wear on wheel brakes increases due to frequent interventions

Engineering Contradiction:
Improvebraking performanceVSAvoidwheel brake service life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The control device operates in a periodic cycle: it continuously monitors wheel speeds and drive train parameters, detects gear shifts and mode changes, temporarily reduces regulation frequency during transitions, and resumes normal continuous regulation when stable operation is detected. This periodic adjustment of regulation intensity maintains braking performance while reducing wear during critical transition phases.

Inventive Principle:
Principle #19Periodic action

3Object-affected harmful factors

If the drive train is powered down during braking to reduce wear, then energy consumption increases, but brake wear is reduced

Engineering Contradiction:
Improvewheel brake wearVSAvoidfuel consumption
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

Instead of completely powering down the drive train during braking, the control device applies partial braking force regulation only when and where needed - specifically reducing or suspending regulation during gear shifts and mode changes. This partial action approach maintains sufficient braking performance while avoiding excessive energy consumption associated with complete drive train shutdown, thereby reducing brake wear without significantly increasing fuel consumption.

Inventive Principle:
Principle #16Partial or excessive action

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

This approach enhances driving comfort by reducing the number of brake interventions, lowering wear on wheel brakes, and achieving efficient traction without powering down the drive train, which in turn reduces fuel consumption.

Implementation Method 1

The control device is supplied with signals from speed sensors assigned to the wheels

Methodology Applied
Scientific EffectSpeed sensing:

Implementation Method 2

During braking of the vehicle, depending on the properties of the wheels and the condition of the road surface, slip occurs between one or more wheels and the road. If the limit area of adhesion between the wheel and the road is reached due to the slip that occurs, the wheel or wheels may lock and slip on the road

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3222477B1Method of operating an agricultural vehicle and an agricultural vehicle
Publication Date: 2020.11.18 CLAAS TRACTOR
  • EP3222477B1 patent drawingFigure 1
  • EP3222477B1 patent drawingFigure 2
  • EP3222477B1 patent drawingFigure 3a~3c

AI summary

A method is used to operate an agricultural vehicle (24), in particular a tractor, wherein the vehicle (24) has a drive train (1) with wheels (4, 5) arranged on a first vehicle axle (2) and a second vehicle axle (3), a transmission (7), and a braking system (15) for applying wheel brakes (14) depending on the wheel braking behavior. A control device (16) is provided for controlling the application of the wheel brakes (14), to which signals are supplied by the speed sensors (23) assigned to the wheels (4, 5) and evaluated, so that the braking force of the respective wheel brake (14) is individually controlled. The method of the type mentioned above is to be further developed in such a way as to increase driving comfort.Furthermore, the application of the wheel brake (14) of at least one wheel (4, 5) shall be controlled as a function of a force and/or a torque transmitted by the drive train (1) to the at least one wheel (4, 5).