Inertial Sensor Angle Accuracy via Frequency-Synchronized Sampling
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Solution Overview
Problem
Inertial sensors face challenges in accurately calculating angles due to integration errors caused by variations in the resonant frequency of angular rate detection elements, leading to increased costs and complexities in synchronization and communication errors between sensors and microcomputers.
Innovation Solution
An inertial sensor design where the angular rate detection circuit is synchronized with the resonant frequency of the angular rate detection element, using a common clock source to maintain consistent sampling intervals and reduce integration errors, and incorporating a memory to store the resonant frequency for accurate angle calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the operation clock of the angular rate detection circuit is synchronized with the resonant frequency of the angular rate detection element, then the detection accuracy is improved, but the sampling interval varies due to frequency variation, causing integration errors
Solution Approach 1:
The patent applies feedback by measuring the actual resonant frequency of the angular rate detection element and using this measured frequency to dynamically adjust the sampling interval. The frequency measurement unit continuously monitors the resonant frequency, and the sampling interval is automatically corrected based on this feedback, ensuring accurate integration despite frequency variations.
Solution Approach 2:
The patent replaces the mechanical assumption of fixed sampling intervals with a computational approach. Instead of relying on a fixed mechanical clock synchronized to resonant frequency, the system uses a measurement unit to detect the actual frequency and a calculation unit to adjust the sampling interval mathematically, substituting mechanical precision with measurement and computation.
2Measurement precision
If individual correction after assembling the sensor is performed to address sampling interval errors, then the angle calculation accuracy is improved, but the time and apparatus required increase, resulting in increased cost
Solution Approach 1:
The patent implements self-service by incorporating the frequency measurement and correction functionality directly into the sensor itself. The sensor autonomously measures its own resonant frequency and performs self-correction of the sampling interval, eliminating the need for external correction apparatus and individual assembly correction processes.
Solution Approach 2:
The patent extracts the frequency measurement and correction functionality from the external correction process and integrates it into the sensor's internal operation. By taking out the correction need from the assembly process and embedding it in real-time operation, the system eliminates post-assembly correction apparatus and time requirements.
3Extent of automation
If digital signal processing is used to integrate angular rate, then the angle can be calculated, but the sampling interval error directly affects the integration accuracy
Solution Approach 1:
The patent changes the sampling interval parameter dynamically based on the measured resonant frequency. Instead of using a fixed sampling interval in digital signal processing, the system continuously adjusts the sampling interval parameter to match the actual resonant frequency, ensuring that the integration accuracy is maintained despite frequency variations.
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 approach enables high-accuracy angle output with reduced integration errors, simplifying the system configuration and eliminating the need for external clock sources, thus reducing costs and improving reliability.
Implementation Method 1
an angular rate detection element having a mechanical structure for detecting an angular rate
Data Source
AI summary
In an inertial sensor that includes an angular rate detection circuit having a structure synchronized with a resonant frequency of an angular rate detection element, an object thereof is to realize an angle output having high accuracy with less integration error in an integration circuit for detecting an angle. The inertial sensor includes an angular rate detection element chip C1 that has a mechanical structure for angular rate detection; and a signal processing LSI chip C2 that is angular rate detection circuit for detecting an angular rate from the angular rate detection element chip C1. The signal processing LSI chip C2 calculates an angle by sampling a signal obtained from the angular rate detection element chip C1 at a discrete time synchronized with a drive frequency of the angular rate detection element chip C1.