MEMS Variable Quality Factor via Electromechanical Damping
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Solution Overview
Problem
The integration of a gyroscope and an accelerometer in the same cavity poses challenges due to differing sensitivity requirements, with the gyroscope needing a high quality factor for sensitivity and the accelerometer requiring a low quality factor to prevent non-linear behavior and potential damage from shocks, leading to operational issues.
Innovation Solution
A microelectromechanical or nanoelectromechanical system with electromechanical damping means, comprising a DC power supply, an electrical resistor, and a variable capacitor connected in series, where the capacitor's capacitance varies with the displacement of the suspended mass, allowing for control of the quality factor, enabling easy integration and operation of both sensors in the same cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gyroscope is placed in a low pressure environment to achieve high quality factor for sensitivity, then the gyroscope sensitivity is improved, but the accelerometer will exhibit non-linear behavior and may be damaged from shocks due to lack of damping
Solution Approach 1:
The invention divides the damping control for the gyroscope and accelerometer into separate independent control mechanisms. The gyroscope operates in a low pressure environment with minimal damping for high sensitivity, while the accelerometer has its own electromechanical damping means that can be activated independently to provide shock protection without affecting the gyroscope's operation.
Solution Approach 2:
The invention introduces dynamically controllable electromechanical damping means for the accelerometer that can adjust the quality factor in real-time. This allows the system to switch between high damping (for shock protection) and low damping (for normal operation) modes, adapting to different operational conditions without compromising either sensor's performance.
2Reliability
If the accelerometer is placed in a high pressure environment to achieve low quality factor for shock damping, then the accelerometer shock resistance is improved, but the gyroscope will suffer from reduced sensitivity due to increased damping
Solution Approach 1:
The invention separates the environmental control for each sensor type, allowing the accelerometer to have its own damping mechanism independent of the gyroscope's low pressure environment. This segmentation enables each sensor to operate in its optimal conditions simultaneously within the same device.
Solution Approach 2:
The electromechanical damping means acts as an intermediary mechanism specifically for the accelerometer, providing the necessary shock damping without requiring changes to the overall low pressure environment that would affect the gyroscope. This intermediary damping layer allows the accelerometer to function properly in a low pressure environment while maintaining shock resistance.
3Device complexity
If a fixed quality factor is used for the gyroscope to simplify the design, then the device complexity is reduced, but the system cannot adapt to different operational phases such as startup and normal operation
Solution Approach 1:
The invention implements a dynamically adjustable quality factor for the gyroscope using controllable electromechanical damping means. The damping coefficient can be modified in real-time based on operational requirements, allowing the system to optimize performance for different phases such as startup (where higher damping may be beneficial) and normal operation (where minimal damping is preferred).
Solution Approach 2:
The invention changes the physical parameters of the damping mechanism by varying the electrical characteristics (voltage, current, or resistance) of the electromechanical damping means. This allows continuous adjustment of the quality factor to match different operational requirements without mechanical reconfiguration, maintaining simplicity while enabling adaptability.
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
This solution allows for adjustable damping, enabling the quality factor to be controlled, thus accommodating the needs of both sensors, ensuring proper operation and sensitivity while preventing damage from shocks.
Implementation Method 1
at least one variable capacitor are connected in series, said capacitor being integrated into the structure of the micro and/or nanoelectromechanical system, such that displacement of the suspended mass of the system will cause a variation in the capacitance of the capacitor
Implementation Method 2
A source of damping for the suspended mass is introduced into a micro and/or nanoelectromechanical system
Data Source
AI summary
Inertial sensor comprising a fixed part and at least one mass suspended from the fixed part and means of damping the displacement of the part suspended from the fixed part, said damping means being electromechanical damping means comprising at least one DC power supply source, one electrical resistor and one variable capacitor in series, said variable capacitor being formed partly by the suspended part and partly by the fixed part such that displacement of the suspended part causes a variation of the capacitance of the variable capacitor.