In-Plane Vibrating Beam Accelerometer with Single Anchor Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vibrating beam accelerometers face challenges in bias repeatability and mechanical isolation due to external mechanical forces, such as thermal expansion mismatch, which affect their accuracy and stability over time and varying operating conditions.
Innovation Solution
A vibrating beam accelerometer with an in-plane translational proof mass, planar geometry, discrete lever arms, four-fold symmetry, and a single primary mechanical anchor is designed to minimize bias errors and achieve mechanical isolation, using a micro-electromechanical systems (MEMS) fabrication process, which reduces complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple mechanical anchors are used to connect the accelerometer mechanism to the support base, then mechanical stability is improved, but bias errors increase due to external mechanical forces such as thermal expansion mismatch
Solution Approach 1:
The patent extracts the mechanical connection points from multiple anchors and consolidates them into a single primary mechanical anchor. This removes the disturbing mechanical pathways that transmit external forces (such as thermal expansion mismatch between substrate and mechanism) to the sensitive accelerometer components, thereby eliminating the source of bias errors while maintaining structural stability through the single isolated anchor point.
2Measurement precision
If complex mechanical isolation techniques are used to minimize bias errors, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the complex mechanical isolation structures from the design and replaces them with a single primary mechanical anchor configuration. This extraction of unnecessary mechanical components simplifies the device structure while achieving the same bias error minimization effect, thereby reducing manufacturing complexity and cost without sacrificing measurement precision.
3Measurement precision
If a single primary mechanical anchor is used to achieve mechanical isolation, then bias repeatability is improved, but structural stability may worsen
Solution Approach 1:
The patent introduces the anchor connection structure as an intermediary element between the single primary mechanical anchor and the accelerometer mechanism. This intermediary structure provides the necessary structural stability and force distribution while maintaining the mechanical isolation benefit of the single anchor configuration, thereby resolving the conflict between reduced bias errors and maintained structural integrity.
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 provides improved bias repeatability and mechanical isolation, enhancing the accuracy and reliability of acceleration measurements while reducing size and cost, making it suitable for navigation-grade inertial measurement units.
Implementation Method 1
The resonator resonates at a driven resonant frequency and the received force from the lever arm causes a change in frequency of the resonator
Implementation Method 2
a lever arm mechanically connected to the anchor connection structure at a fulcrum of the lever arm, wherein a first end of the lever arm is mechanically connected to the translational proof mass
Implementation Method 3
the resonator configured to: connect a second end of the lever arm to the anchor; receive a force from the lever arm when the translational proof mass is accelerated; and flex in the second plane based on the received force
Data Source
AI summary
A vibrating beam accelerometer (VBA) with an in-plane translational proof mass that may include at least two or more resonators and be built with planar geometry, discrete lever arms, four-fold symmetry and a single primary mechanical anchor between the support base and the VBA. In some examples, the VBA of this disclosure may be built according to a micro-electromechanical systems (MEMS) fabrication process. Use of a single primary mechanical anchor may minimize bias errors that can be caused by external mechanical forces applied to the circuit board, package, and/or substrate that contains the accelerometer mechanism.