Hybrid Closed-Loop Accelerometer for Extended Range
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Solution Overview
Problem
Traditional closed-loop MEMS accelerometers become inaccurate when input acceleration exceeds the feedback system's maximum response, leading to saturation and a loss of additional acceleration information.
Innovation Solution
Combining closed-loop feedback signals with measured proof-mass position to create a hybrid acceleration measurement, extending the operating range by incorporating the sensor's mechanical open-loop range, without modifying the basic sensor or electronics architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the closed-loop feedback system is used to measure acceleration, then measurement precision is improved within the operating range, but the measurement range becomes limited and saturates when input acceleration exceeds the feedback system's maximum response
Solution Approach 1:
The patent combines the closed-loop feedback signal and the measured proof-mass position into a hybrid acceleration measurement. This merging allows the system to maintain the precision benefits of closed-loop operation while extending the measurement range by incorporating open-loop position data, effectively providing an operating range equal to the traditional closed-loop operating range plus the sensor's mechanical open-loop range
Solution Approach 2:
The patent makes the acceleration measurement system multi-functional by enabling it to operate in both closed-loop mode (for high precision within range) and open-loop mode (for extended range), with automatic transition between modes. This allows a single sensor system to handle both high-precision measurements and wide-range measurements without requiring separate systems
2Adaptability or versatility
If the feedback system operates at maximum response to extend measurement range, then the operating range is extended, but measurement precision is lost due to saturation and proof-mass movement away from null position
Solution Approach 1:
The patent dynamically switches between closed-loop and open-loop measurement modes based on the input acceleration level. When acceleration is within the closed-loop range, the system uses closed-loop feedback for high precision. When acceleration exceeds this range, the system transitions to using the measured proof-mass position, maintaining measurement capability without saturation while preserving accuracy within each operational regime
Data Source
AI summary
A microelectromechanical systems (MEMS) accelerometer with extended operational capabilities beyond a closed-loop saturation. The present invention combines the closed-loop feedback signal and the measured proof-mass position into a hybrid acceleration measurement, which effectively provides an operating range equal to the traditional closed-loop operating range plus the sensor's mechanical open-loop range.