Optical Flow Vehicle Speed and Slip Determination

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Solution Overview

Problem

Existing methods for determining vehicle speed and slip, such as wheel rotation monitoring and GPS, are prone to inaccuracies due to tire slippage and lateral forces during cornering, and are not suitable for consumer use or in obstructed locations.

Innovation Solution

An optical flow technology-based system using an image sensor and optical lens on a vehicle to capture images of the traveling surface, calculating pixel speeds in longitudinal and lateral directions, and determining vehicle speed and slip values for accurate performance monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If wheel rotation monitoring is used to determine vehicle speed, then the measurement method is simple and widely applicable, but the accuracy deteriorates due to tire slippage and lateral forces during cornering

Engineering Contradiction:

Improveease of implementationVSAvoidspeed measurement accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical wheel rotation monitoring system with an optical flow-based vision system. The image sensor captures images of the traveling surface, and optical flow algorithms calculate pixel displacement to determine vehicle speed and slip, eliminating the need for mechanical contact with the wheel and thereby removing the source of measurement error from tire slippage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary optical measurement system that observes the traveling surface through an optical lens rather than directly measuring wheel rotation. This intermediary approach allows indirect measurement of vehicle motion through pixel flow analysis, providing accurate speed and slip data without being affected by tire deformation or slippage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If GPS is used to determine vehicle speed, then the measurement can be performed in obstructed locations, but the accuracy deteriorates due to signal obstruction and is not suitable for consumer use

Engineering Contradiction:

Improveoperational environment flexibilityVSAvoidspeed measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces GPS satellite-based electromagnetic signal reception with a local optical flow measurement system using image sensors. This substitution enables speed measurement in obstructed locations where GPS signals are blocked, while maintaining high accuracy through direct optical observation of the traveling surface and pixel displacement analysis.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If optical flow technology is used to determine vehicle speed and slip, then the measurement accuracy is improved, but the device complexity increases due to image sensor and processing requirements

Engineering Contradiction:

Improvespeed and slip measurement accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the image sensor perform multiple functions: capturing images for optical flow analysis, determining vehicle speed, calculating side slip, and measuring longitudinal slip. This multi-functionality reduces the need for separate sensors and systems, thereby managing complexity while providing comprehensive vehicle dynamics measurement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The optical flow system uses the image sensor's inherent capabilities to perform all measurements without requiring additional dedicated components. The same image data used for optical flow processing also provides information for calculating speed, slip angles, and other vehicle dynamics parameters, allowing the system to serve itself across multiple measurement needs.

Inventive Principle:

Principle #25Self-service

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

Provides accurate and reliable measurements of vehicle speed and slip, including side slip and longitudinal slip, directly from pixel flow analysis, improving vehicle performance monitoring and operational adjustments.

Implementation Method 1

receiving a sequence of images of a traveling surface captured by an image sensor using an optical lens

Methodology Applied

Scientific EffectOptical energy detection: Photoelectric Effect

Data Source

PatentUS20230237766A1Speed And Slip Determinations For A Vehicle Using Optical Flow Technology

Publication Date: 2023.07.27 MICHIGAN SCIENTIFIC CORP

AI summary

A vehicle speed and/or slip of a vehicle is determined. At least first and second images of a traveling surface captured by an image sensor using an optical lens are received by a processor. The images are used to determine the distance travelled by one or more pixels in first and second directions. These distances, along with the sampling rate of the image sensor, determine pixel speed in the first and second directions. The pixel speeds in the first direction, the second direction, or both, may be used to calculate the vehicle speed, a side slip angle, or a longitudinal slip. A tire speed may also be similarly determined using a second image sensor, a second optical lens, and a second processor capturing images of the tire surface. These vehicle parameters may be used for testing or operating the vehicle, including modifying vehicle behavior during operation.