Micro-electromechanical Apparatus with Pivot Element for Multi-Axis Inertial Sensing
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Solution Overview
Problem
Current micro-electromechanical inertial measurement units (IMUs) face challenges in miniaturization due to excessive area and high manufacturing costs, as well as signal coupling and complexity in readout circuits, particularly when trying to integrate three-axis accelerometers and gyroscopes with independent masses, which limits their effectiveness in GPS signal-shielded environments.
Innovation Solution
A micro-electromechanical apparatus with a substrate, first anchors, pivot elements, and a rotating frame that surrounds the pivot elements, where the pivot ends are connected to the anchors and the rotary ends to the frame, with a constant distance from the pivot ends to the axis, allowing for reduced overall area and improved miniaturization while maintaining sensitivity and accuracy in detecting angular velocities and accelerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three masses of the accelerometer and three masses of the gyroscope are designed to move independently to prevent signal interference, then measurement precision is improved, but device complexity and overall area increase excessively
Solution Approach 1:
The patent combines the gyroscope oscillator mass and accelerometer sensing mass into a single shared mass structure. The gyroscope oscillator rotates about a vertical axis while the accelerometer senses acceleration along the rotation axis, allowing both functions to operate simultaneously without requiring separate independent masses, thereby reducing overall device area while preventing signal interference through functional separation.
Solution Approach 2:
The shared mass structure serves dual functions: it acts as the oscillating mass for the gyroscope to detect angular velocity around the vertical axis, and simultaneously serves as the sensing mass for the accelerometer to detect acceleration along the vertical axis. This multi-functional design eliminates the need for separate masses while maintaining measurement precision for both sensors.
2Measurement precision
If a hollow disc-like oscillator is used for the gyroscope to generate oscillation in two perpendicular directions, then measurement capability is improved, but the central region becomes unavailable for additional sensors
Solution Approach 1:
Instead of placing the oscillator in the center and excluding other sensors from the central region, the patent inverts the arrangement by positioning the oscillator around the periphery and placing the accelerometer in the central region. The gyroscope oscillator rotates about a vertical axis passing through the center, while the accelerometer is disposed at the center to sense acceleration along this axis, allowing both sensors to coexist without interference.
3Adaptability or versatility
If the IMU integrates both accelerometer and gyroscope functions, then navigation capability in GPS-shielded areas is improved, but manufacturing cost and area increase
Solution Approach 1:
The patent merges the accelerometer and gyroscope into a single integrated micro-electromechanical apparatus with a shared mass structure. The gyroscope oscillator and accelerometer share common structural elements including the mass, support beams, and electrode arrangements, reducing the number of separate components that need to be manufactured and assembled, thereby lowering manufacturing costs while providing full six-degree-of-freedom navigation capability.
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 enables a compact and cost-effective IMU that can provide accurate navigation information in GPS-shielded areas by reducing the overall area and manufacturing complexity, while minimizing signal interference and maintaining sensitivity across multiple axes.
Implementation Method 1
a first frame configured to rotate with respect to an axis passing through the region
Implementation Method 2
a distance between each of the pivot ends and the axis is equal to a constant
Data Source
AI summary
A micro-electromechanical apparatus may include a substrate, a first frame, a plurality of first anchors, a region and a plurality of pivot elements. The plurality of first anchors and the region is disposed on the substrate. The region is surrounded by the plurality of first anchors. Each of the pivot elements includes a pivot end and a rotary end. Each of the pivot ends is connected to a corresponding first anchor and each of the rotary ends is connected to the first frame such that the first frame is able to rotate with respect to an axis passing the region. The micro-electromechanical apparatus having the pivot elements and the region is adapted for detecting multi-degree physical quantities such as angular velocities in at least two axes, angular velocities and accelerations, angular velocities and Earth's magnetic field.