Cornering Force Calculation via Wheel Acceleration Sensors
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Solution Overview
Problem
Existing methods for accurately measuring cornering force in vehicle tires are limited by the need for pre-obtained relationships between tire deformation and forces, which are difficult to establish and cannot account for various conditions encountered during actual vehicle travel, such as load changes and tire rotation states.
Innovation Solution
A cornering force calculating method and device that uses sensor units on each wheel to measure acceleration data, processing this information to derive contact length, width direction deformation, and centrifugal force, allowing for accurate calculation of cornering force through a data processing unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indoor cornering test devices are used to measure cornering force, then measurement can be performed in controlled conditions, but accuracy is insufficient because the devices cannot reproduce various actual traveling conditions (load changes, tire rotation states)
Solution Approach 1:
The patent replaces complex mechanical test devices with a computational approach using sensors and calculations. Acceleration sensors mounted on the vehicle body measure acceleration data, which is then processed through coordinate transformation and integration to derive cornering force, eliminating the need for physical test equipment that cannot adapt to various traveling conditions
Solution Approach 2:
The patent changes the measurement parameters from direct mechanical force measurement to acceleration-based indirect measurement. By measuring acceleration in multiple directions and transforming these parameters through coordinate systems, the system can accurately calculate cornering force under varying load conditions and tire rotation states that mechanical devices cannot reproduce
2Ease of operation
If sensors are used to measure tire deformation and estimate cornering force, then measurement can be performed on actually mounted tires, but the method requires pre-obtained relationship between tire deformation and forces which is difficult to establish
Solution Approach 1:
The patent replaces the complex approach of establishing pre-obtained tire deformation-force relationships with a direct acceleration-based calculation method. By mounting acceleration sensors on the vehicle body and using coordinate transformation with integration, the system directly calculates cornering force without requiring empirical relationship data
Solution Approach 2:
The patent extracts the essential measurement function from complex tire deformation analysis and simplifies it to acceleration-based measurement. By taking out only the necessary acceleration data in three directions and processing it through coordinate transformation, the method eliminates the need for complex pre-established relationships between tire deformation and forces
3Measurement precision
If acceleration sensors are mounted on each wheel to measure acceleration data, then cornering force can be calculated under various actual traveling conditions, but the device complexity increases
Solution Approach 1:
The patent merges the measurement functions into a centralized data processing unit that handles all sensor data. Instead of having independent measurement systems at each wheel, the acceleration sensors are integrated into a unified system that performs coordinate transformation and calculation of cornering forces for all wheels through centralized processing
Solution Approach 2:
The data processing unit serves multiple functions: it processes acceleration data from multiple sensors, performs coordinate transformations for different reference systems, calculates cornering forces for multiple wheels, and can determine various vehicle dynamics parameters. This multi-functionality reduces the need for separate dedicated systems for each measurement task
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 easy and accurate calculation of cornering force for each wheel, accounting for various conditions and improving the accuracy of cornering force measurement during vehicle travel.
Implementation Method 1
a sensor unit provided to each wheel measures acceleration data of a predetermined portion of a tire
Implementation Method 2
the data processing unit calculates a magnitude of a cornering force generated in each wheel, based on the derived contact length, the derived amount of width direction deformation of each wheel, and a magnitude of a centrifugal force applied to the vehicle
Data Source
Figure 1
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Figure 3A~3B
AI summary
A method of calculating a cornering force to be applied to each wheel provided to a vehicle which is cornering, comprising the steps of: obtaining a magnitude of a centrifugal force to the vehicle in a direction substantially orthogonal to a vehicle traveling direction, a contact length of each wheel during the cornering of the vehicle, and an amount of deformation in a wheel width direction at the contact portion of each wheel of the vehicle, calculating a difference between the obtained amount of the deformation and an amount of deformation in the wheel width direction under a straight forward travel condition of the vehicle for each wheel, and calculating a cornering force for each wheel based on the magnitude of the centrifugal force, the contact length, and the difference between amounts of deformation in the wheel width direction.