Vehicle Air Drag Model Updating from Visual Shape Changes

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Solution Overview

Problem

Existing air drag models for heavy vehicle combinations are inadequate when the exterior shape changes during a transport mission, such as when trailers are added or removed, as they require costly wind tunnel tests or numerical simulations for validation, and online estimation is unreliable due to chaotic wind conditions.

Innovation Solution

A method that uses images of the vehicle combination to estimate a projected area function and update a crosswind-sensitive air drag model, automatically detecting changes in the exterior shape and adjusting the model without the need for expensive experiments or simulations, by employing image analysis to determine the new projected area function and its dependence on air-attack angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wind tunnel tests or numerical simulations are used to obtain air drag model parameters, then the accuracy of the air drag model is improved, but the cost and time required increase significantly

Engineering Contradiction:

Improveair drag model parameter accuracyVSAvoidtime for wind tunnel tests or simulations

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent uses image data to create a visual copy or representation of the vehicle combination's exterior shape, from which the projected area function is estimated. This avoids the need for physical wind tunnel tests or complex numerical simulations, significantly reducing time and cost while maintaining acceptable accuracy for the application

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical testing system (wind tunnel experiments) and complex computational system (CFD simulations) with an image-based estimation system. This substitution uses computer vision and image processing techniques to estimate the projected area function, achieving a balance between accuracy and efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If wind tunnel tests are performed to update the air drag model after exterior shape changes, then the model remains valid, but the process becomes tedious and costly

Engineering Contradiction:

Improvevalidity of air drag modelVSAvoidease of model updating

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The system performs self-updating of the air drag model by automatically detecting exterior shape changes through images and estimating the new projected area function. This eliminates the need for manual intervention to conduct new wind tunnel tests or simulations whenever the vehicle combination configuration changes

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent implements a feedback mechanism where the system continuously monitors the vehicle combination's exterior shape through images, detects changes, and automatically updates the air drag model parameters accordingly. This closed-loop approach ensures the model remains valid without requiring external validation through costly testing

Inventive Principle:

Principle #23Feedback

3Productivity

If online estimation techniques are used to capture crosswind sensitivity, then the model can be updated in real-time, but the results are disturbed by chaotic wind behavior

Engineering Contradiction:

Improvereal-time model updating capabilityVSAvoidaccuracy of online estimation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces image data as an intermediary medium between the vehicle combination and the air drag model estimation. Instead of directly measuring wind effects on the moving vehicle (which are subject to chaotic wind behavior), the system uses static or quasi-static images to estimate the projected area function, thereby eliminating the disturbance from chaotic wind conditions while maintaining real-time update capability

Inventive Principle:

Principle #24Intermediary (Mediator)

4Measurement precision

If the air drag model is updated frequently to account for configuration changes, then the model accuracy is maintained, but the complexity of the system increases

Engineering Contradiction:

Improveair drag model accuracyVSAvoidsystem complexity for model maintenance

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a universal image-based estimation approach that can handle various types of exterior shape changes (different vehicle combinations, trailer configurations, etc.) using the same fundamental methodology. This multi-functional system reduces complexity by avoiding the need for different updating procedures for different scenarios

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20230382402A1Air drag model estimation using visual information

Publication Date: 2023.11.30 VOLVO TRUCK CORP

AI summary

A computer-implement method of estimating air drag for a vehicle combination is provided. The method includes detecting a change of an exterior shape of the vehicle combination to a new exterior shape. The method includes, in response to detecting such a change, and based on one or more images of the vehicle combination captured after the change, estimating a projected area function indicating a dependence of a projected frontal area of the vehicle combination having the new exterior shape on air-attack angle. The method includes using the estimated projected area function to update a crosswind-sensitive air drag model for the vehicle combination.