Single Sensor Speed Detection via Signal Decoupling
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Solution Overview
Problem
Existing methods for measuring the speed of rotating machinery lack accuracy and reliability, particularly in detecting faults and analyzing vibrations, as they require multiple signals and are prone to noise interference.
Innovation Solution
An apparatus and method that generate two speed measurements from a single signal using a sensor to detect a moving element, with a sensor conditioning unit decoupling the signal into AC and DC components, processed by a timer/counter and analog-to-digital converter to provide accurate and verifiable speed data, and adjustable trigger criteria to mitigate noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor signal is used for speed measurement, then device complexity is reduced, but measurement precision deteriorates due to noise interference
Solution Approach 1:
The single sensor signal is segmented into multiple processing paths: a first path processes the raw signal for basic speed measurement, while a second path applies filtering and noise reduction techniques. This segmentation allows the system to maintain simple hardware (single sensor) while achieving high measurement precision through divided signal processing workflows.
2Measurement precision
If multiple processing paths are used to improve speed measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent resolves processing complexity by transitioning from temporal processing (multiple sensors over time) to spectral processing (frequency domain analysis). The second processing path transforms the signal into the frequency domain, where noise can be selectively filtered without affecting the fundamental speed measurement information, thereby improving precision without proportionally increasing system complexity.
3Reliability
If signal filtering is applied to reduce noise, then reliability is improved, but loss of information increases due to potential signal distortion
Solution Approach 1:
The patent applies partial filtering through the second processing path, where only specific frequency components are filtered based on the known characteristics of speed measurement signals. Rather than applying aggressive filtering that would distort the signal, the system uses moderate, targeted filtering that removes noise while preserving the essential speed information, achieving improved reliability with minimal information loss.
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 provides detailed, accurate speed measurements that are reliable and resistant to noise, enabling effective fault detection and vibration analysis in machinery, enhancing the monitoring of rotating equipment.
Implementation Method 1
The sensor may be an eddy current sensor, a hall effect sensor, a light sensor
Implementation Method 2
The sensor may be an eddy current sensor, a hall effect sensor, a light sensor
Data Source
AI summary
Two speed measurements of a moving body are generated using a single signal. A sensor generates a composite signal having a series of pulses where each pulse is generated when an element on a moving body passes the sensor. A sensor conditioning unit decouples the composite signal to generate a first conditioned sub-signal having only an AC signal corresponding to an AC component of the composite signal and a second conditioned sub-signal corresponding to the composite signal that may have either or both AC and DC components. A timer/counter input unit computes a first speed measurement by determining a count of pulses in the first conditioned sub-signal and a first time period or the time period of one pulse. The second conditioned sub-signal is transmitted to an analog-to-digital converter (ADC) and is sampled at a sampling rate to generate a sampled second conditioned sub-signal. An acquisition unit computes a second speed measurement by determining a count of pulses in the sampled second conditioned sub-signal over a second time period or the time of a single pulse. An analysis of the second conditioned sub-signal may be used to choose trigger or filter criteria for the analysis of both conditioned sub-signals, and multiple speed sensors may be used with each sensor producing two speed measurements.