Mode-Localized Inertial Sensor with Tunable Resonator Coupling
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Solution Overview
Problem
Inertial sensors that rely on mode localization face limitations in sensitivity and resolution due to challenges in manufacturing weak mechanical couplings, which are also not robust, leading to sensor failure and reduced sensitivity from inaccuracies in fabrication and material defects.
Innovation Solution
An inertial sensor design that includes a resonator assembly with a mechanical coupling and a pumping signal, where the pumping signal adjusts the energy transfer between resonators, allowing for a higher scale factor and sensitivity while using relatively strong mechanical couplings, which are easier to manufacture and more robust, and can be tuned to mitigate fabrication inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the coupling strength between resonators is minimized to maximize sensor sensitivity, then the scale factor and sensitivity increase, but the mechanical coupling becomes difficult to manufacture accurately and less robust
Solution Approach 1:
The patent applies parameter changes by introducing a pumping signal that dynamically adjusts the effective coupling strength between resonators. Instead of relying solely on fixed mechanical coupling parameters, the system modulates the coupling through parametric excitation, allowing the effective coupling to be tuned independently of the physical manufacturing parameters. This resolves the contradiction by decoupling the sensitivity optimization from manufacturing precision constraints.
Solution Approach 2:
The patent transforms the static mechanical coupling into a dynamic system by applying a pumping signal at specific frequencies. The coupling strength becomes time-dependent and controllable through the pumping signal parameters, allowing the system to achieve optimal sensitivity conditions dynamically while using robust, easily manufacturable mechanical structures.
2Measurement precision
If the mechanical coupling is made very weak to maximize sensitivity, then the scale factor increases, but the coupling becomes non-robust and prone to sensor failure
Solution Approach 1:
The pumping signal changes the effective parameters of the coupling mechanism dynamically. By modulating the system at specific frequencies, the effective coupling strength can be reduced for sensing purposes while the physical coupling remains strong and robust, preventing sensor failure while maintaining high sensitivity.
Solution Approach 2:
The patent employs periodic pumping signals to create time-varying coupling conditions. The periodic modulation allows the system to achieve weak effective coupling during specific phases of the cycle for high sensitivity, while the overall mechanical structure remains strongly coupled and robust throughout operation.
3Measurement precision
If the coupling strength is reduced to enhance eigenstate changes, then the sensitivity improves, but fabrication errors cause extreme mode localization that loses signal in noise
Solution Approach 1:
The pumping signal dynamically changes the system parameters to optimize the balance between mode localization and signal detectability. By controlling the pumping frequency and amplitude, the system can achieve sufficient mode localization for sensitivity while preventing extreme localization that would bury the signal in noise.
Solution Approach 2:
The system uses feedback control to monitor the mode localization and adjust the pumping signal parameters accordingly. This ensures optimal sensitivity is maintained while preventing extreme localization conditions that would degrade the signal-to-noise ratio.
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
The solution significantly enhances the sensitivity and resolution of inertial sensors by allowing for a higher scale factor, making them more robust and easier to manufacture, while the pumping signal adjusts the coupling strength to maintain optimal performance across a range of input values.
Implementation Method 1
applying a pumping signal that has a frequency substantially equal to a difference between the first resonant frequency and the second resonant frequency
Implementation Method 2
The resonator assembly has a first resonant frequency at which an amplitude of vibration of the first resonator is maximised and a second resonant frequency at which an amplitude of vibration of the second resonator is maximised
Implementation Method 3
a first and second resonator coupled to one another by a mechanical coupling and a drive means coupled to the resonator assembly for driving the first and second resonators to vibrate
Data Source
AI summary
There is provided an inertial sensor comprising a frame, a resonator assembly fixed to the frame comprising a first and second resonator coupled to one another by a mechanical coupling and a drive means coupled to the resonator assembly for driving the first and second resonators to vibrate. The resonator assembly is configured such that energy is transferred between the first and second resonators through the mechanical coupling. An amount of energy transferred through the mechanical coupling is dependent on the value of an input measurand acting on one of the first and second resonators. The inertial sensor also comprises a pumping means coupled to the resonator assembly for applying a pumping signal to the resonator assembly, the pumping means controlled by electrical circuitry, and a sensor assembly configured to detect the amplitude of oscillation of the first resonator at a first resonant frequency and the amplitude of oscillation of the second resonator at a second resonant frequency. The electrical circuitry is configured to control the pumping means to apply a pumping signal that has a frequency substantially equal to a difference between the first resonant frequency and the second resonant frequency. When the input measurand has the first value, the signal from the pumping means adjusts an amplitude ratio of the amplitudes of oscillation of the first and second resonator detected by the sensor assembly so that the amplitude ratio is within a predetermined amplitude ratio range over an expected range of input measurand values. An output of the inertial sensor is based on the amplitude ratio.