Flexural Pivot Micro-Sensor for Tilt Measurement
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Solution Overview
Problem
Existing force sensors are bulky, expensive, and lack sensitivity, making them difficult to handle and mount due to their small size and fragility, while attempts to miniaturize them lead to handling and mounting challenges.
Innovation Solution
A micro-sensor design featuring a fixed reference frame with an elastic pivot and a moveable body that rotates about the pivot, creating opening and closing gaps to detect tilt and measure separation, with gauges configured to measure strain caused by inputs, allowing for sensitivity enhancement and improved handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If force sensors are miniaturized to reduce size and bulk, then sensitivity and cost-effectiveness improve, but handling and mounting become difficult due to fragility
Solution Approach 1:
The sensor is divided into a fixed reference frame and a moveable body that can rotate independently about the pivot. This segmentation allows the moveable body to be smaller and more sensitive while the fixed frame provides structural support for handling and mounting, resolving the contradiction between miniaturization and ease of operation.
Solution Approach 2:
The pivot structure is designed with specific local properties - an elastic pivot with defined stiffness characteristics that provides rotational freedom for the moveable body while maintaining overall structural integrity. This localized design enables the sensor to be miniaturized without compromising handling ease.
2Measurement precision
If the gauge length is reduced to increase sensitivity, then measurement precision improves, but the sensor becomes more fragile and difficult to handle
Solution Approach 1:
The pivot enables rotational motion, adding a dimensional aspect to the sensor operation. The moveable body rotates about the pivot, allowing the gauge to measure strain through rotational displacement rather than linear displacement. This dimensional change increases sensitivity while maintaining structural robustness against fragility.
Solution Approach 2:
The moveable body is designed with asymmetric mass distribution or geometric features that enhance rotational sensitivity about the pivot. This asymmetric design amplifies the measurement signal for a given input while keeping the overall structure reliable and handleable.
3Measurement precision
If leverage is increased to amplify strain signal, then measurement sensitivity improves, but device complexity increases
Solution Approach 1:
The pivot structure merges the leverage mechanism with the rotational degree of freedom. Instead of separate leverage arms and rotation joints, the elastic pivot itself provides both the mechanical advantage for strain amplification and the rotational capability, simplifying the overall device structure while maintaining high sensitivity.
Solution Approach 2:
The elastic pivot serves multiple functions simultaneously: it acts as a rotational joint, provides mechanical leverage for strain amplification, and serves as the elastic element that generates the measurement signal. This multi-functionality reduces device complexity while achieving high 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 design provides a compact, cost-effective, and sensitive force sensor capable of measuring high acceleration forces with reduced bulk, improved handling, and enhanced sensitivity, suitable for both linear and rotational acceleration measurements.
Implementation Method 1
an elastic pivot. The elastic pivot has at least two co-axial segments of pivot and is coupled to the fixed reference frame
Implementation Method 2
The gauge is, therefore, strained in an amount which depends upon that force. This change in resistance is determined by means of electrical current flowing through the element from one pad to the other
Data Source
AI summary
A micro-sensor is provided with a fixed reference frame and an elastic pivot. The elastic pivot has at least two co-axial segments of pivot and is coupled to the fixed reference frame. The elastic pivot has a neutral axis that is a central line of the pivot. A moveable body is coupled to the elastic pivot and the reference frame. The moveable body and the reference frame share a reference surface. The moveable body extends between the two co-axial segments to provide that for a rotation of the moveable body about the pivot the moveable body approaches the reference surface at a first side, and recedes from the reference surface from an opposite side to provide an opening gap and a closing gap. The neutral axis is below the reference surface. At least a first gauge is configured to detect tilt about the elastic pivot and measure separation of the moveable body and the reference frame at the reference surface. The gauge provides a measurement of the opening and closing of the opening and closing gaps. Inputs to be measured cause the moveable body to rotate about the pivot and strain the gauge.