Vehicle Vibration Coefficient Calibration for Position Measurement
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Solution Overview
Problem
Existing position measurement techniques for vehicle-type moving bodies face challenges in accurately determining movement velocity due to the diversity of vehicle types and road surfaces, requiring a calibration of the relation between vibration and movement velocity for each road surface.
Innovation Solution
An information processing device that acquires sensor measurements from a vehicle, calculates a vibration feature quantity using FFT of acceleration values, and computes a road vibration coefficient to define the relationship between vibration and movement velocity, enabling precise position measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration-based dead reckoning is used for position measurement, then position measurement capability is enabled, but measurement precision deteriorates due to diversity of vehicle types and road surfaces
Solution Approach 1:
The patent applies local quality by introducing a road vibration coefficient that is specific to each road surface type. Instead of using a single universal vibration-velocity relationship, the system calibrates and stores separate coefficients for different road surfaces (asphalt, concrete, gravel, etc.), allowing the measurement system to adapt locally to each surface type and thereby improve position measurement precision.
Solution Approach 2:
The patent employs parameter changes by making the vibration-velocity relationship dynamic rather than static. The road vibration coefficient serves as a changeable parameter that is selected based on the detected road surface type, enabling the system to adjust its measurement characteristics to match the specific conditions of each road surface and vehicle combination.
2Measurement precision
If road vibration coefficient calibration is performed for each road surface, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by performing calibration of road vibration coefficients in advance for various road surface types and storing these coefficients in a database. During actual position measurement, the system simply retrieves the pre-calibrated coefficient corresponding to the detected road surface type, avoiding the need for real-time calibration and significantly reducing operational complexity.
Solution Approach 2:
The patent introduces an intermediary element in the form of a road surface detection mechanism and coefficient database. This intermediary layer translates the physical road surface conditions into selected vibration coefficients, thereby decoupling the complexity of calibration from the real-time measurement process and simplifying the overall system operation.
3Measurement precision
If vibration feature quantity is calculated from acceleration values, then position measurement is enabled, but loss of information occurs due to frequency band limitations
Solution Approach 1:
The patent applies partial action by selectively excluding only the DC component and very low frequency bands from the vibration feature quantity calculation, while retaining all other frequency components. This partial exclusion removes information that does not contribute to vibration-based velocity measurement (DC and near-DC components) while preserving all useful vibration information for accurate position measurement.
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 allows for the determination of a road vibration coefficient that accurately represents the relationship between vibration and movement velocity, enhancing the accuracy of position measurement across various road surfaces and vehicle types.
Implementation Method 1
an acquisition section that acquires a measurement value which has been measured by a sensor provided in a vehicle while the vehicle is traveling on a road surface
Implementation Method 2
a vibration feature quantity calculation section that calculates a vibration feature quantity Pv(t) based on expressions below from acceleration values for respective x, y, and z components... which have been obtained by FFT from the acceleration values
Implementation Method 3
a road vibration coefficient calculation section that calculates a road vibration coefficient ρ based on the vibration feature quantity Pv(t) which has been calculated and an expression below, Pv(t)=ρ·v(t)2 where v(t) is a velocity of the vehicle
Data Source
AI summary
A road vibration coefficient which defines a relation between vibration and a movement velocity of a vehicle during traveling is obtained. An information processing device includes: an acquisition section that acquires a measurement value which has been measured by a sensor provided in a vehicle while the vehicle is traveling on a road surface; a vibration feature quantity calculation section that calculates a vibration feature quantity Pv(t); anda road vibration coefficient calculation section that calculates a road vibration coefficient ρ.