Acceleration Measurement via Phase Demodulation of Electrical Signals
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Solution Overview
Problem
Existing accelerometer technologies face challenges in accurately measuring acceleration due to noise and direct current signal components, which affect the precision of position encoding and subsequent acceleration calculations.
Innovation Solution
An apparatus and method that utilize a spring-mounted mass with a positional encoder outputting sine and cosine signals, processed by a decoder to calculate acceleration, incorporating a correction processor and quadrature-to-phase converter to remove noise and extract acceleration from these signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase modulation is used to encode position as instantaneous phase of a carrier wave, then measurement precision is improved, but noise and direct current signal components affect the accuracy
Solution Approach 1:
The patent extracts and removes the harmful direct current component from the phase-modulated signal through differential processing. By calculating the difference between successive phase measurements, the system eliminates the DC offset while preserving the acceleration information contained in the phase variations.
Solution Approach 2:
The patent introduces an intermediary processing stage that converts phase measurements to acceleration through a defined mathematical relationship. This intermediary transformation allows the system to separate the useful acceleration signal from noise and DC components by exploiting the known relationship between phase modulation and acceleration.
2Measurement precision
If positional encoder outputs sine and cosine signals for position encoding, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the decoder universal by designing it to process both sine and cosine signals from the positional encoder. This multi-functional decoder can extract position information from either signal type, reducing the need for separate processing paths and actually simplifying the overall device architecture despite the increased signal processing requirements.
3Reliability
If driver maintains oscillation of spring-mounted mass, then measurement reliability is improved, but energy consumption increases
Solution Approach 1:
The patent employs periodic oscillation of the spring-mounted mass as the fundamental measurement mechanism. By maintaining continuous periodic motion at a defined frequency, the system ensures reliable acceleration measurements while allowing for energy-efficient resonance-based operation where the oscillation is sustained with minimal energy input.
Data Source
AI summary
In accordance with embodiments of the present disclosure, an apparatus for measuring acceleration may include a spring-mounted mass, a positional encoder configured to measure a position of the spring-mounted mass and output one or more signals indicative of a sine and a cosine of the position, a driver to set and maintain an oscillation of the spring-mounted mass, and a decoder configured to process the one or more signals to calculate an acceleration of the spring-mounted mass.