Virtual Tachometer via Vibration Signal Processing

Solution Overview

Problem

The use of physical tachometers for condition monitoring in complex rotating machinery is hindered by system latencies, inaccuracies, high costs, and reliability issues due to spatial distribution and multiple gearboxes, as well as environmental and installation-related degradations.

Innovation Solution

A virtual tachometer system that processes vibration data from a single transducer to derive a frequency of interest, generate a sinusoidal signal, and count zero crossings to define blocks for time synchronous averaging calculations, eliminating the need for multiple physical tachometers and reducing costs and inaccuracies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple physical tachometers are used to monitor rotating machinery components, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improverotational speed detection accuracyVSAvoidnumber of tachometers required

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual tachometer by processing vibration signals from a single physical sensor to generate synthetic tachometer outputs. The system extracts rotational speed information from vibration data and generates virtual tachometer signals that replicate the function of multiple physical tachometers without requiring them physically present at each monitoring point.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical tachometer system with a computational approach. Instead of using multiple physical tachometers to detect rotational speed, the system uses a single vibration sensor combined with signal processing algorithms (including FFT analysis and envelope detection) to computationally determine rotational speed and generate virtual tachometer signals.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple physical tachometers are installed throughout the system, then measurement precision is improved, but weight and cost increase

Engineering Contradiction:

Improverotational speed detection accuracyVSAvoidtotal system weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent creates a virtual tachometer by processing vibration signals from a single physical sensor to generate synthetic tachometer outputs. The system extracts rotational speed information from vibration data and generates virtual tachometer signals that replicate the function of multiple physical tachometers without requiring them physically present at each monitoring point.

Inventive Principle:

Principle #26Copying

3Device complexity

If a global tachometer is used for processing dynamic data, then device complexity is reduced, but measurement precision deteriorates due to system latencies and inaccuracies

Engineering Contradiction:

Improvenumber of processing unitsVSAvoiddynamic data accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by processing vibration signals locally at each monitoring point using a single sensor and computational algorithm, rather than using a centralized global processor. This local processing approach eliminates transmission delays and ensures that dynamic data is processed with minimal latency while maintaining high accuracy, as the signal is analyzed directly where it is generated.

Inventive Principle:

Principle #3Local quality

4Measurement precision

If physical tachometers are used in dirty environments, then measurement capability is maintained, but reliability deteriorates due to environmental degradation

Engineering Contradiction:

Improverotational speed detectionVSAvoidtachometer operation stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical/physical tachometer system with a computational approach. Instead of using multiple physical tachometers to detect rotational speed, the system uses a single vibration sensor combined with signal processing algorithms (including FFT analysis and envelope detection) to computationally determine rotational speed and generate virtual tachometer signals.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 accurate detection of small speed variations in rotating machinery components, enhancing condition monitoring and reliability while providing monetary and weight penalty cost savings and ease of implementation.

Implementation Method 1

receive a plurality of first inputs from a transducer, the plurality of first inputs corresponding to vibrations of a rotational machine

Methodology Applied

Scientific EffectVibration: Vibration

Data Source

PatentUS10444254B2Virtual tachometers based on time series filtering

Publication Date: 2019.10.15 SIKORSKY AIRCRAFT CORP

AI summary

A system and method for receiving a plurality of first inputs from a transducer, where the plurality of first inputs correspond to vibrations of a rotational machine, and filtering the plurality of first inputs to derive a frequency of interest. The system and method then generates a sinusoidal signal at the frequency of interest and a pulse train of one or multiple pulses per revolution at the frequency of interest from the sinusoidal signal. The system and method further identifies a first pulse at a zero crossing within the pulse train and counts zero crossings to define blocks of data for use in time synchronous averaging calculations.