Oscillator Frequency Control via Acoustic Fourier Analysis

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Solution Overview

Problem

Existing methods for controlling mechanical oscillators in motor vehicles, such as vibration motors, are unreliable due to material fatigue and aging, leading to inaccurate frequency determination and potential undesired superpositions, and require additional complex sensors that are prone to damage and errors.

Innovation Solution

A method using a single sound transducer to capture and analyze electrical signals from oscillators, transforming them into Fourier spectra to determine and adjust frequencies, eliminating the need for additional sensors and simplifying control by correlating extreme values with desired frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional sensors (pulse sensors, inductive sensors, Hall sensors, or optical sensors) are provided on the oscillators to determine and adjust frequency during operation, then measurement precision is improved, but device complexity increases and reliability deteriorates due to additional components that oscillate with the oscillators and are damaged over time

Engineering Contradiction:

Improvefrequency determination accuracyVSAvoidnumber of sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a sound transducer as an intermediary device that indirectly measures the oscillation frequency of the mechanical oscillators by detecting sound waves they produce. This mediator approach allows frequency measurement without direct contact with the oscillating components, avoiding the damage issues that plague direct-mounted sensors while maintaining measurement accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical/direct-contact sensors (pulse sensors, inductive sensors, Hall sensors) with an acoustic measurement system using a sound transducer. This substitution eliminates the need for physical mounting on the oscillators, thereby removing the source of sensor damage and aging while preserving frequency measurement capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If the frequency of oscillators is determined by recording and inferring from the relationship between applied power and frequency when embedded in medium, then device complexity is reduced, but measurement precision deteriorates due to material fatigue and aging processes leading to changes in the relationship

Engineering Contradiction:

Improvesensor requirementsVSAvoidfrequency determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the indirect inference method (based on power-frequency relationships that degrade over time) with direct acoustic measurement using a sound transducer. This substitution provides accurate real-time frequency measurement without relying on aging-sensitive calibration curves, thereby maintaining measurement precision while keeping the system simple.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system continuously monitors oscillator frequency through acoustic measurement and provides feedback to adjust the oscillators' operation. This real-time feedback mechanism compensates for any drift in oscillator characteristics without relying on pre-recorded power-frequency relationships that are susceptible to material aging.

Inventive Principle:

Principle #23Feedback

3Device complexity

If oscillators are not coordinated with each other, then device complexity is reduced, but harmful factors increase due to undesired superpositions of oscillations leading to undesired beats

Engineering Contradiction:

Improvecontrol coordinationVSAvoidundesired beats

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The system uses acoustic measurement to monitor the frequencies of multiple oscillators and implements feedback control to coordinate them. By continuously measuring and adjusting oscillator frequencies based on real-time data, the system prevents undesired superpositions and beats while maintaining relatively simple oscillator design.

Inventive Principle:

Principle #23Feedback

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 allows for precise and reliable control of oscillators without additional sensors, reducing damage and errors, and preventing undesired superpositions like beats, while maintaining accurate frequency determination over time.

Implementation Method 1

sensing the oscillations of at least two oscillators by means of a sound transducer

Methodology Applied

Scientific EffectSound transducer conversion: Piezoelectric Effect

Implementation Method 2

transforming the recorded signal into a Fourier spectrum

Methodology Applied

Scientific EffectFourier transform:

Data Source

PatentUS11548423B2Method for controlling at least two mechanical oscillators

Publication Date: 2023.01.10 MERCEDES BENZ GROUP AG

AI summary

A method for controlling at least two mechanical oscillators, more particularly in a motor vehicle, where each oscillator oscillates at a frequency during operation and where the frequency can be controlled by the power applied to the oscillators, includes arranging a single sound transducer at a distance from the oscillators and capturing an electrical signal, where the electrical signal is subjected to a Fourier transform and thus a Fourier spectrum is determined. The frequency of each oscillator is determined from extreme values of the Fourier spectrum.