Tire Flexibility Estimation Under Stable Steering Conditions
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Solution Overview
Problem
Existing methods for estimating tire state changes, such as wear and deterioration, lack accuracy and are prone to noise from disturbances and driving style variations.
Innovation Solution
An information processing device that calculates tire flexibility using specific conditions to ensure a constant force application, employing feature quantities like gradients of wheel velocities and accelerations, to accurately detect gradual and rapid tire state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods use general sensor data to estimate tire state changes, then the estimation can be performed continuously, but the accuracy is low and prone to noise from disturbances and driving style variations
Solution Approach 1:
The patent changes the parameters used for tire state estimation from general sensor data to specific feature quantities (gradients of wheel velocities and accelerations) calculated under controlled conditions. By selecting specific parameters that are less sensitive to disturbances and driving style variations, the estimation accuracy is improved while reducing the impact of harmful noise factors.
Solution Approach 2:
The patent applies local quality by ensuring that feature quantities are calculated under specific local conditions (when steering wheel angle and angular velocity are within reference ranges). This localized approach ensures that the force applied to the tire is within a certain range, reducing the impact of disturbances and improving measurement precision for tire state changes.
2Measurement precision
If feature quantities are calculated without specific conditions, then the calculation can be performed continuously, but the force applied to the tire fluctuates reducing estimation accuracy
Solution Approach 1:
The patent changes the calculation approach by introducing specific parameter thresholds (steering wheel angle and angular velocity reference ranges). Feature quantities are only calculated when these parameters are within the reference ranges, ensuring that the force applied to the tire is stable and within a certain range, thereby improving estimation accuracy.
Solution Approach 2:
The patent applies preliminary action by checking whether the steering wheel angle and angular velocity are within reference ranges before calculating feature quantities. This preliminary check ensures that the force applied to the tire is stable before performing the calculation, preventing fluctuations that would reduce estimation accuracy.
Data Source
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AI summary
An information processing method includes determining whether at least one condition is satisfied, and calculating a feature quantity on flexibility of a tire (41; 42; 43; 44) when all of the at least one condition is satisfied. The at least one condition includes at least one of a first condition that an absolute value of an angular velocity (ω) of a steering wheel is smaller than a first reference value (ωref), and a second condition that an absolute value of a vector sum of vehicle accelerations (G) of the vehicle (1) including the steering wheel and wheels (400) each provided with the tire (41; 42; 43; 44) is smaller than a second reference value (Gref).