Precision Angular Position Sensor Using Coarse and Fine Measurement Fusion
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Solution Overview
Problem
Traditional angular measurement sensors, such as RVDTs and resolvers, are limited in displacement, leading to inaccurate and imprecise measurements, particularly in applications like tiltrotor aircraft where precise angular position measurement is crucial.
Innovation Solution
A method combining coarse and fine measurements using multiple sensors, where a fine relative angular measurement is made by a sensor capable of multiple revolutions and a coarse absolute measurement is provided by another sensor, allowing for high precision absolute angular measurements over a physical travel range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensors like RVDTs or resolvers are used for angular measurement, then the measurement range is limited (RVDTs to 80°, resolvers to one revolution), but the device complexity remains relatively simple
Solution Approach 1:
The measurement system is segmented into two independent sensors: a coarse sensor (RVDT or resolver) that provides absolute position over a limited range, and a fine sensor (optical or magnetic encoder) that provides high-resolution relative measurements over multiple revolutions. By dividing the measurement function across two sensors with complementary capabilities, the system achieves extended measurement range while maintaining manageable complexity through functional specialization.
Solution Approach 2:
The patent combines the outputs of two different sensor types through signal processing and data fusion. The coarse absolute measurement from the first sensor is merged with the fine relative measurement from the second sensor to produce a unified high-precision angular position reading that leverages the strengths of both sensor technologies.
2Measurement precision
If gear reduction is used to extend measurement range, then the sensor can measure larger displacements, but the accuracy and resolution of the measurement are limited by the electrical output of the sensor
Solution Approach 1:
The system dynamically switches between coarse and fine measurement modes depending on the application requirements. The fine sensor operates at high resolution for precision work, while the coarse sensor provides absolute positioning when needed. This dynamic capability allows the system to adapt its measurement characteristics rather than being constrained by fixed mechanical gearing.
Solution Approach 2:
The patent replaces mechanical gear reduction with an electronic/software-based solution that combines measurements from two sensors. Instead of using mechanical gears to amplify limited sensor range, the system uses digital signal processing to synthesize extended-range measurements, eliminating mechanical complexity and preserving full sensor resolution.
3Measurement precision
If multiple resolvers are used to achieve required accuracy, then measurement accuracy is improved, but the wiring becomes very complex
Solution Approach 1:
The fine sensor (optical or magnetic encoder) serves multiple functions: it provides high-resolution relative angular measurements, enables multi-revolution tracking, and works in conjunction with the coarse sensor to deliver both absolute and relative positioning capabilities. This multi-functionality reduces the need for multiple specialized sensors and their associated wiring.
Data Source
AI summary
A method and system to measure a parameter associated with a component, device, or system with a specified accuracy, including: providing one or more sensors operably disposed to detect the parameter; obtaining a coarse measurement of the parameter within a first range using the one or more sensors, wherein the first range includes minimum and maximum values for the parameter; obtaining a fine measurement of the parameter within a second range using the one or more sensors, wherein the second range is smaller than the first range and has a specified ratio to the first range that provides the specified accuracy; determining a current value of the parameter by combining the coarse and fine measurements; and providing the current value of the parameter to a communications interface, a storage device, a display, a control panel, a processor, a programmable logic controller, or an external device.