Inertia Force Sensor Signal Summing for Detection Sensitivity
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Solution Overview
Problem
Conventional inertial force sensors have low detection sensitivity due to the small output current from sensing electrode parts, which limits their effectiveness in detecting angular rates and accelerations in mobile structures.
Innovation Solution
The inertial force sensor employs a detecting element with orthogonally coupled arms and a weight, driven by alternating-current voltage, generating a Coriolis force that induces strain in the arms, which is sensed by piezoelectric electrodes, and the output current is amplified through differential and summing circuits to enhance detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional sensing electrode part with piezoelectric element is used to detect strain, then the sensor can detect angular rate and acceleration, but the output current is very small and detection sensitivity is low
Solution Approach 1:
The patent combines the output currents from multiple sensing electrode parts (first and second sensing electrode parts) into a single amplified output. By merging the signals from both arms of the detecting element, the system achieves higher output current and improved detection sensitivity compared to using a single sensing electrode part.
Solution Approach 2:
The patent transitions from detecting strain in a single dimension to detecting strain in multiple orthogonal dimensions by using both first and second sensing electrode parts oriented at right angles to each other. This multi-dimensional sensing approach increases the overall signal output and detection capability.
2Volume of moving object
If the strain of the detecting element is very slight when detecting angular rate or acceleration, then the sensor structure remains compact, but the output current becomes very small
Solution Approach 1:
The patent merges the output signals from multiple sensing electrode parts to compensate for the small individual signals resulting from slight strain. By combining the currents from both the first and second sensing electrode parts, the system maintains compact dimensions while achieving sufficient output signal strength through signal summation.
Solution Approach 2:
The patent uses duplicate sensing electrode parts (first and second sensing electrode parts) positioned orthogonally to each other. These copies of the sensing mechanism work together to produce a combined output that is stronger than individual sensors, allowing compact design with enhanced signal output.
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
This configuration significantly improves the detection sensitivity of angular rates and accelerations, enabling more precise position control and navigation in mobile structures by effectively amplifying the feeble current signals from the sensing electrodes.
Implementation Method 1
a sensing electrode part consisting of upper electrode and lower electrode with an intervening piezoelectric element is disposed in the detecting element, and the angular rate or acceleration is detected on the basis of the current flowing out from the sensing electrode part accompanied by strain of the detecting element
Implementation Method 2
the strain of the detecting element accompanied by generation of Coriolis force is sensed electrically, and the angular rate is detected
Data Source
Figure 1
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AI summary
When detecting an angular rate in a detecting element (1), when an angular rate occurs, it is detected on the basis of a first sum by adding output values issued from upper electrode of second sensing electrode part (19b) and upper electrode of fourth sensing electrode part (20b) both in positive polarity, a second sum by adding output values issued from upper electrode of first sensing electrode part (19a) and upper electrode of third sensing electrode part (20a) both in negative polarity, a third sum by adding output values issued from lower electrode of first sensing electrode part (19a) and lower electrode of third sensing electrode part (20a) both in positive polarity, and a fourth sum by adding output values issued from lower electrode of second sensing electrode part (19b) and lower electrode of fourth sensing electrode part (20b) both in negative polarity. In this configuration, the inertial force sensor enhanced in detection sensitivity is presented.