Velocity Estimation Using Characteristic Frequency

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Solution Overview

Problem

Existing methods for estimating the velocity of objects, such as vehicles or people, are limited in accuracy and reliability, particularly when using inertial signals from accelerometers, as they often fail to account for coupled movements and rotational accelerations effectively.

Innovation Solution

The use of accelerometer signals to determine a characteristic frequency through frequency spectrum analysis or model application, allowing for the estimation of velocity by multiplying the characteristic frequency with a proportionality factor, which can include wheel radius for wheeled vehicles, and incorporating sensor fusion with additional sensor signals for improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If accelerometer signals are used to estimate velocity, then velocity estimation can be performed without GPS or radar, but the accuracy and reliability of velocity estimation deteriorates due to failure to account for coupled movements and rotational accelerations

Engineering Contradiction:
Improvevelocity estimation capabilityVSAvoidvelocity estimation accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the acceleration measurement into two distinct components: translational acceleration (from the first accelerometer in the vehicle) and rotational acceleration (from the second accelerometer in the wheel). By separating these coupled movements into independent measurement channels, the system can accurately distinguish between linear motion and rotational motion, thereby resolving the accuracy problem while maintaining the versatility of accelerometer-based velocity estimation.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If only translational acceleration is measured, then the measurement system remains simple, but the velocity estimation becomes unreliable when rotational movements are present

Engineering Contradiction:
Improveaccelerometer configurationVSAvoidvelocity estimation reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a processing unit as an intermediary that receives acceleration signals from both the vehicle-mounted accelerometer and the wheel-mounted accelerometer. This intermediary component performs the critical function of separating translational and rotational acceleration components through signal processing, enabling reliable velocity estimation without requiring complex mechanical coupling between the sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If coupled movements are not accounted for, then the velocity estimation process remains straightforward, but the results become inaccurate in scenarios with rotational acceleration

Engineering Contradiction:
Improvevelocity estimation processVSAvoidvelocity estimation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent performs preliminary separation of translational and rotational acceleration components before conducting velocity estimation. By pre-processing the acceleration signals to isolate the translational component (which directly relates to vehicle velocity) from the rotational component, the system maintains a straightforward velocity estimation process while ensuring accurate results even in the presence of rotational movements.

Inventive Principle:
Principle #10Preliminary 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 the accuracy of velocity estimation by accounting for both translational and rotational movements, reducing uncertainty and increasing reliability, especially in scenarios where objects are coupled or partially coupled, and enables applications in navigation and localization systems.

Implementation Method 1

accelerometer signals, which indicate an acceleration of a first object and/or a second object

Methodology Applied
Scientific EffectInertial measurement: Inertia

Implementation Method 2

a frequency spectrum analysis may be performed on the accelerometer signals to obtain an accelerometer signal spectrum

Methodology Applied
Scientific EffectFrequency spectrum analysis:

Data Source

PatentUS10969401B2Velocity estimation
Publication Date: 2021.04.06 NIRA DYNAMICS AB
  • US10969401B2 patent drawing
  • US10969401B2 patent drawing
  • US10969401B2 patent drawing

AI summary

The present disclosure relates to the estimation of a velocity of a first object using accelerometer signals, indicating an acceleration of the first object and/or a second object coupled to a first object. To this end, a characteristic frequency in the accelerometer signal spectrum may be determined, preferably by applying a parametric model or by performing a spectrum analysis, and used as a basis to estimate the velocity of the first object based on the determined characteristic frequency. The characteristic frequency may be determined by identifying the frequency having the maximum spectral amplitude or by identifying the fundamental frequency or a particular harmonic in the spectrum.