Self-Calibrating Wheel Accelerometer Using Signal Amplitude
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional accelerometers mounted on vehicle wheels experience significant performance drift over time, requiring frequent and costly calibration, and are inaccurate when operating outside the calibrated range of +1 g to -1 g due to wider operational ranges encountered on vehicles.
Innovation Solution
A method for self-calibrating accelerometers while a vehicle is moving by calculating the gain and offset using the average and amplitude of acceleration signals over a defined time window, filtered with specific frequency filters, allowing dynamic calibration independent of wheel diameter and refining values during stationary periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If accelerometers are calibrated within a range of between +1 g and −1 g to avoid causing components to accelerate, then component safety is improved, but measurement accuracy deteriorates when operating within much wider ranges (0 g to 100 g) encountered on vehicles
Solution Approach 1:
The patent changes the calibration parameters by using the amplitude of acceleration signals at known wheel rotation speeds to determine gain and offset values, rather than using traditional static calibration methods. This allows the accelerometer to be calibrated for the wider operational range (0-100 g) while maintaining component safety during calibration.
2Measurement precision
If accelerometers are regularly calibrated to maintain performance levels, then measurement accuracy is improved, but cost increases due to frequent calibration operations
Solution Approach 1:
The patent implements self-calibration functionality that allows the accelerometer to automatically determine its own gain and offset parameters using data from normal vehicle operation. The system uses the known relationship between wheel rotation speed and acceleration signal amplitude to perform calibration without external intervention, eliminating the need for costly professional calibration services.
Solution Approach 2:
The patent enables continuous calibration during normal vehicle operation by constantly monitoring acceleration signals and updating gain and offset values. This continuous self-calibration process maintains measurement accuracy throughout the vehicle's operational life without requiring periodic shutdowns or professional calibration interventions.
3Adaptability or versatility
If accelerometers are mounted on vehicle wheels to measure parameters over wide ranges, then versatility is improved, but performance drift increases over time requiring frequent recalibration
Solution Approach 1:
The patent implements a feedback mechanism where the accelerometer continuously monitors its own output signals and compares them against expected values based on wheel rotation speed. The system uses this feedback to detect performance drift and automatically adjusts gain and offset parameters to compensate, maintaining reliability over the wide operational range without requiring external recalibration.
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
Enables accurate and cost-effective continuous calibration of accelerometers, improving their performance and accuracy across wider operational ranges, reducing the need for frequent recalibration and maintaining precise measurements.
Implementation Method 1
an accelerometer having a plane of maximum sensitivity and designed to supply a signal representative of gravity
Data Source
AI summary
A method for self-calibrating, while a vehicle is moving, an accelerometer mounted on a wheel of the vehicle so that its plane of maximum sensitivity is secant with the axis of rotation of the wheel. The average value and on the other hand the amplitude of the signal representative of the acceleration Acc-read delivered by the accelerometer are calculated first, for an established speed of the vehicle, based on measurements performed by the accelerometer during a time window corresponding to the time needed for the wheel to complete n rotations, with n>1, then the values of the gain C1 and of the offset C2 of the accelerometer are determined by resolving the system of two equations with two unknown values:ω2R=C1×(average value of Acc-read)+C22 g=C1×(amplitude of Acc-read)with:ω the speed of rotation of the wheel,R the radius of the wheel.