Vehicle Length Estimation Using Chassis-Mounted Detector

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Solution Overview

Problem

Existing systems for determining the configuration of moving vehicles, especially with trailers, face challenges in precision due to changing parameters and the need for frequent recalibration, leading to suboptimal active safety systems.

Innovation Solution

A system that uses a detector unit suspended in the vehicle's chassis to measure the vehicle's length by detecting a vehicle reference point and calculating the pivot angle based on wheel speeds and geometrical relationships, allowing for continuous and robust estimation of vehicle configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If sensors are fitted in the vehicle's rearview mirrors to measure vehicle length continuously, then measurement continuity is improved, but measurement precision deteriorates due to the sprung cab rocking and moving

Engineering Contradiction:
Improvemeasurement continuityVSAvoidvehicle length measurement precision
Core Design Contradiction:
Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The detector unit is extracted from the sprung cab (rearview mirror area) and relocated to the vehicle chassis, which remains stationary relative to the vehicle's reference frame. This extraction eliminates the interference of cab suspension movement while maintaining continuous measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The measurement system is segmented into two independent parts: the detector unit mounted on the stationary chassis and the moving sprung cab with trailer. By measuring from the chassis reference frame, the system separates the measurement origin from the suspension movements, achieving both continuity and precision.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If calibration is done mechanically when the vehicle's length changes, then adaptability to different configurations is improved, but device complexity and time consumption increase

Engineering Contradiction:
Improveadaptability to different trailer configurationsVSAvoidcalibration system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system performs self-calibration by automatically detecting the trailer's rear edge position and calculating vehicle length parameters using the detector unit on the chassis. No manual mechanical calibration is needed, as the system adapts automatically to different trailer configurations through continuous detection and geometric calculation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Manual mechanical calibration is replaced by an automated optical/electronic detection system. The detector unit uses light-based detection (camera or optical sensor) to identify the trailer rear edge, and a computer calculates the measurements, substituting mechanical calibration procedures with automated sensing and computation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If the detector unit is mounted on the sprung cab, then ease of installation is improved, but measurement reliability deteriorates due to continuous movement and rocking

Engineering Contradiction:
Improveease of installationVSAvoidmeasurement reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The detector unit is extracted from the unreliable sprung cab mounting location and relocated to the stable vehicle chassis. This extraction maintains installation feasibility while dramatically improving measurement reliability by eliminating suspension-induced movements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The detector unit is positioned on the chassis at a location that serves as a stable reference potential point, unaffected by suspension dynamics. This creates a measurement reference frame that is equipotential relative to vehicle movements, ensuring reliable and consistent measurements regardless of cab or trailer position.

Inventive Principle:
Principle #12Equipotentiality

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 enables better control and safety by providing accurate and continuous measurements of vehicle length and geometry, enhancing active safety systems like lane holding and emergency veering, while reducing the risk of accidents by detecting potential hazards.

Implementation Method 1

The vehicle reference point is detected by a detector unit (radar, camera or the like) situated on the vehicle

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

The vehicle reference point is detected by a detector unit (radar, camera or the like) situated on the vehicle

Methodology Applied
Scientific EffectLIDAR: LIDAR

Data Source

PatentEP2487454B1Vehicle length estimation
Publication Date: 2018.12.19 SCANIA CV AB
  • EP2487454B1 patent drawingFigure 1
  • EP2487454B1 patent drawingFigure 2~3
  • EP2487454B1 patent drawing

AI summary

The invention relates to a method for determining the configuration of a moving vehicle, which method comprises: identifying when the vehicle pivots, and generating on the basis thereof a pivot signal ST; detecting at least one vehicle reference point by means of a detector unit situated on the vehicle when the vehicle pivots, and generating on the basis thereof a reference signal SR; determining on the basis of said reference signal a linear distance between said vehicle reference point and the detector unit, and generating on the basis thereof a distance signal SD; determining for the vehicle a pivot angle α related to said vehicle reference point, and generating on the basis thereof a pivot angle signal Sα; calculating a vehicle length on the basis of at least said linear distance and said pivot angle when the vehicle pivots, and generating on the basis thereof a vehicle length signal SL. The invention comprises also a system for determining the configuration of a moving vehicle.