Inertial Sensor Connection Portion for High Q Factor
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Solution Overview
Problem
Inertial sensors with high Q factors are required for advanced autonomous driving systems, but existing sensors face challenges in maintaining high accuracy due to vibration energy dissipation at the connection points between the vibrator and the mounting substrate.
Innovation Solution
The inertial sensor design includes a mounting substrate with electrodes, a hollow rim vibrator, and a connection portion with linear portions extending along node directions. This configuration minimizes vibration energy dissipation by restricting transmission at antinode positions, thereby maintaining a high Q factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the vibrator is connected to the mounting substrate at multiple points, then the connection strength is improved, but vibration energy dissipation increases and Q factor decreases
Solution Approach 1:
The connection portion is designed with varying properties: linear portions along node directions provide strong connection while circular portions at antinode positions provide weak connection. This local differentiation allows the connection to be strong where needed (node directions) and weak where vibration energy dissipation occurs (antinode positions), resolving the contradiction between connection strength and energy loss.
Solution Approach 2:
The connection portion is segmented into distinct linear portions and circular portions, each serving different functions. The linear portions extend along node directions to provide structural support, while the circular portions are positioned at antinode positions to minimize vibration energy dissipation. This segmentation allows independent optimization of connection strength and energy conservation.
2Stability of the object's composition
If the connection area between vibrator and mounting substrate is increased, then the mechanical stability is improved, but vibration energy dissipation increases
Solution Approach 1:
The connection portion has non-uniform properties: linear portions with higher connection strength are positioned along node directions to provide mechanical stability, while circular portions with lower connection strength are positioned at antinode positions to reduce vibration energy dissipation. This local quality differentiation resolves the contradiction between mechanical stability and energy conservation.
3Ease of manufacture
If conventional connection methods are used, then the manufacturing process is simple, but the Q factor cannot be maintained at high levels
Solution Approach 1:
The connection portion's geometry is optimized by changing parameters: linear portions extend along node directions and circular portions are positioned at antinode positions. This parameter optimization maintains manufacturability while significantly improving the Q factor and angular velocity detection accuracy, resolving the contradiction between manufacturing simplicity and measurement precision.
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 proposed design effectively suppresses vibration energy dissipation, leading to an improved Q factor and enhanced accuracy in angular velocity detection, which is crucial for advanced autonomous driving systems.
Implementation Method 1
The connection portion has a plurality of linear portions extending linearly along node directions, which are directions along substrate radial directions centering on a mounting center of a connection area between the mounting surface and the mounting substrate and passing through positions of vibration nodes of the rim that vibrates in a resonant mode of n=k
Data Source
AI summary
An inertial sensor includes a mounting substrate, a vibrator, and a connection portion. The mounting substrate has electrodes arranged apart from each other. The vibrator has a hollow rim, and a mounting portion having a mounting surface facing the mounting substrate. The connection portion is disposed between the mounting surface of the mounting portion and the mounting substrate to connect therebetween. The electrodes are arranged in a ring shape around the rim at a distance from the rim. The connection portion has a plurality of linear portions extending linearly along node directions, which are directions along substrate radial directions centering on a mounting center of a connection area between the mounting surface and the mounting substrate and passing through positions of vibration nodes of the rim that vibrates in a resonant mode of n=k, in which k is an integer of 2 or more.