Proximity Sensing for High-Fidelity Shaft Angle Measurement
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Solution Overview
Problem
Conventional methods for determining the angular position of a rotating shaft in jet turbines, such as those used in blade stress tests and rig builds, suffer from poor angular fidelity due to reliance on 1/rev or multi-tooth sensors and time of arrival estimates.
Innovation Solution
A system utilizing a sensor to measure the distance between a rotating target with a varying radius and a stationary sensor, coupled with a computing device to determine the rotational angular position based on known profile data of the target, enabling high-accuracy non-contact measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional 1/rev or multi-tooth sensors are used to determine angular position, then the measurement system is simple, but the angular fidelity is poor
Solution Approach 1:
The patent replaces conventional mechanical toothed sensors with a non-contact proximity sensor system. The proximity sensor measures the varying gap distance to a rotating target with an eccentric profile, substituting mechanical tooth detection with electromagnetic or capacitive field-based distance measurement, thereby achieving higher angular fidelity without mechanical contact
Solution Approach 2:
The patent changes the measurement parameter from discrete tooth position detection to continuous gap distance measurement. By measuring the continuous variation in distance between the proximity sensor and the eccentric target surface, the system achieves higher resolution angular position information compared to discrete tooth-based methods
2Measurement precision
If time of arrival estimates are used for angular measurement, then the system is simple, but the measurement accuracy is insufficient
Solution Approach 1:
The patent replaces time-of-arrival estimation methods with a direct distance measurement system. The proximity sensor continuously measures the actual gap distance to the target, eliminating the need for time-based calculations and providing direct spatial information for more accurate angular determination
Solution Approach 2:
The patent introduces an eccentric target profile as an intermediary between the shaft and the proximity sensor. This target with its varying radius profile acts as a mediator that converts rotational position into measurable gap distance variations, enabling high-precision angular measurement through distance measurement rather than direct time or position sensing
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
Achieves high angular positional accuracy within tenths of a degree by correlating the change in gap between the sensor and target surface to the amount of rotational angular change, providing precise angular position determination.
Implementation Method 1
a sensor configured to measure a distance between the sensor and an outer surface of the target
Data Source
AI summary
A system includes a shaft configured to rotate about an axis. The system also includes a target coupled to the shaft and having a radius that varies around a circumference of the target. The system further includes a sensor configured to measure a distance between the sensor and an outer surface of the target. In addition, the system includes at least one processing device configured to receive at least one distance measurement from the sensor and determine a rotational angular position of the shaft based on the at least one distance measurement and known profile data of the target.