Shaft Angular Position Estimation from Runout Vibration Signals
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Solution Overview
Problem
Existing methods for determining the angular position of a shaft require hardware marks or phase reference signals, which are not always available, especially in continuously operating machines or small equipment, limiting diagnostic capabilities and increasing costs.
Innovation Solution
A method using vibration measurements from contactless sensors, such as eddy current sensors, to estimate the angular position of a shaft by processing displacement signals and identifying characteristic signal signatures, allowing for the reconstruction of the angular position without physical references.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hardware marks or phase reference signals are installed on the shaft, then the angular position measurement precision is improved, but the device complexity and manufacturing costs increase
Solution Approach 1:
The shaft itself serves as the reference by utilizing its inherent runout characteristics. The method processes vibration signals to extract the runout pattern, which naturally provides angular position information without requiring external reference marks or additional sensors. This self-service approach eliminates the need for hardware modifications while maintaining measurement precision.
Solution Approach 2:
Instead of using physical reference marks on the shaft, the invention creates a virtual reference by copying the runout pattern from the vibration signals. The runout signature is extracted and processed to generate angular position estimates, effectively replacing physical markers with a signal-based reference that requires no additional hardware.
2Measurement precision
If hardware marks are installed on the shaft, then the angular position can be determined accurately, but the ease of operation is worsened due to required machine shutdown and access to rotor surface
Solution Approach 1:
The system uses the shaft's own runout characteristics as the reference, eliminating the need for physical installation of markers during maintenance shutdowns. The vibration sensors continuously capture runout patterns, enabling angular position determination during normal operation without interrupting the machine cycle.
Solution Approach 2:
The invention replaces the mechanical installation of hardware marks with a signal processing approach. Instead of physically attaching reference elements to the rotor surface, the system substitutes mechanical reference markers with electronic signal analysis of vibration data, allowing continuous operation and eliminating maintenance interruptions.
3Measurement precision
If temporary phase reference with reflective tape and optical sensor is installed, then the angular position measurement is enabled, but additional costs and operational problems are incurred
Solution Approach 1:
The shaft's inherent runout serves as the reference instead of requiring temporary reflective tape and optical sensors. The vibration sensors already present on the machine capture the runout pattern, eliminating the need for additional temporary instrumentation and reducing both costs and installation complexity.
Solution Approach 2:
The vibration sensors serve multiple functions: they monitor vibration levels for condition monitoring and simultaneously extract runout patterns for angular position determination. This multi-functionality eliminates the need for separate phase reference instrumentation, reducing costs and simplifying the measurement system.
4Device complexity
If no phase reference is available, then the hardware complexity is reduced, but the measurement precision and diagnostic capabilities are significantly reduced
Solution Approach 1:
The system extracts angular position information from the shaft's own runout characteristics using existing vibration sensors. This self-service approach maintains measurement precision and diagnostic capabilities without requiring additional reference marks or phase reference signals, keeping the device simple while preserving full diagnostic functionality.
Solution Approach 2:
The invention creates a virtual phase reference by copying the runout pattern from vibration signals. This signal-based reference enables accurate angular position measurement and full diagnostic capabilities without physical hardware marks, maintaining measurement precision while keeping the system simple and cost-effective.
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
Enables accurate determination of the shaft's angular position using existing instrumentation, reducing costs and enhancing diagnostic capabilities, particularly in scenarios where hardware marks are absent, and allowing for continuous operation.
Implementation Method 1
the sensor may also be used without any displacement (herewith referring to a perfect cylinder). The signal may also be impacted by material composition variation. Such displacement signal is also referred to as so-called runout
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
The invention provides a solution for determining a rotating shaft's angular position in the absence of hardware marks on such shaft.