Trailer Coupling Load Sensing for Accurate Trailer Mass Estimation

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Solution Overview

Problem

Existing trailer coupling systems fail to accurately determine the mass of a trailer, which is crucial for safe towing, as they do not effectively measure and adjust for vertical and tensile loads, and do not account for factors like friction, inertial masses, and temperature variations.

Innovation Solution

A trailer coupling system that utilizes a force sensor to measure deformation caused by tensile force, combined with an evaluation device that considers acceleration, friction, and temperature, and optionally includes an inclination sensor to determine trailer mass by evaluating force signals and acceleration values, taking into account factors like air resistance and rolling friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If only a force sensor is used to measure tensile load, then the device complexity is reduced, but the measurement precision of trailer mass is insufficient

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines multiple measurement functions (tensile load measurement, vertical load measurement, and acceleration measurement) into a single integrated evaluation device. The force sensor measures both tensile and vertical loads, while the acceleration sensor provides additional data for mass calculation, merging multiple sensing functions into one system to reduce overall device complexity while maintaining measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The evaluation device is designed to perform multiple functions: it processes force sensor signals for load measurement, integrates acceleration sensor data for mass determination, performs temperature compensation, and calculates trailer mass. This multi-functional approach eliminates the need for separate dedicated devices for each measurement task.

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

2Measurement precision

If temperature compensation is implemented using a separate temperature sensor, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The temperature sensing and compensation function is merged into the existing evaluation device rather than being implemented as a separate system. The evaluation device integrates temperature sensor input with force and acceleration signal processing, performing temperature compensation for the force sensor readings within the same computational framework used for mass determination.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple sensors (force sensor, acceleration sensor, temperature sensor, inclination sensor) are integrated into one evaluation device, then the measurement precision and reliability are improved, but the device complexity increases

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple sensor inputs (force sensor, acceleration sensor, temperature sensor, and inclination sensor) into a single evaluation device that processes all signals integrally. This centralized processing approach improves reliability by ensuring coordinated operation of all sensors while managing complexity through unified signal processing algorithms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The evaluation device is designed as a universal platform that handles multiple sensor types and performs various functions including force measurement, acceleration measurement, temperature compensation, inclination compensation, and trailer mass calculation. This multi-functional design consolidates what would otherwise require multiple separate devices.

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

4Device complexity

If the force sensor measures both tensile load and vertical load, then the device complexity is reduced, but the measurement precision of individual loads may be compromised

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The force sensor is designed with multi-functional capability to measure both tensile loads (in the towing direction) and vertical loads (support load on the coupling ball) simultaneously. The evaluation device processes the force sensor output signals to separately determine each load component, enabling a single sensor to perform multiple measurement functions.

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

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

Accurately determines the trailer mass by compensating for various factors, ensuring safe towing conditions and providing precise load measurements, even under varying inclinations and environmental conditions.

Implementation Method 1

a force sensor, for example a force sensor dedicated to determining a deformation of the trailer coupling, in particular of the coupling support or the bracket, caused by tensile force

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

The acceleration value is an acceleration value in the direction of travel or x-direction

Methodology Applied
Scientific EffectAcceleration: Accelerometer

Implementation Method 3

the evaluation device has a temperature sensor so that it can carry out temperature compensation

Methodology Applied
Scientific EffectTemperature compensation: Temperature Gradient

Implementation Method 4

the trailer coupling or its evaluation device also includes an inclination sensor for determining an inclination angle

Methodology Applied
Scientific EffectInclination angle measurement: Spirit Level

Data Source

PatentEP3698993B1Draw bar with an evaluation device
Publication Date: 2025.10.22 WESTFALIA AUTOMOTIVE
  • EP3698993B1 patent drawingFigure 1~2
  • EP3698993B1 patent drawingFigure 3~4
  • EP3698993B1 patent drawingFigure 5~7

AI summary

The invention relates to a trailer coupling (10, 110) for a towing vehicle (90), comprising a coupling support (14; 114) which in particular includes a coupling arm, at the free end of which a coupling element (23), in particular a coupling ball (22), for attaching a trailer (92) is arranged and which is fixedly or movably arranged on a bracket (11; 111) attached or attachable to the towing vehicle (90), and with at least one force sensor (30) for detecting a tractive load (Fx) acting on the coupling element (23) during towing operation of the trailer (92) and for outputting a force signal (33) representing the tractive force and/or thrust. An evaluation unit (50; 150) is provided which is configured to determine a trailer mass value of the trailer (92) based on the force signal (33) and an acceleration value.