Tire Force Estimation Using Dynamic Bank Angle Transitions
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Solution Overview
Problem
Existing systems fail to accurately estimate tire forces when a vehicle is in a bank state, particularly during transitions such as the beginning or end of turning, where the bank angle changes over time.
Innovation Solution
A processor unit that estimates tire forces by monitoring the change in the vehicle's motion state within a plane perpendicular to the forward-rearward axis, using equations that balance the motion state changes with applied forces, allowing for accurate estimation of vertical, lateral, and forward-rearward forces even during bank angle transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tire forces are estimated using balance equations of centrifugal and gravitational forces, then tire force estimation is possible, but accuracy deteriorates during transit states when bank angle changes over time
Solution Approach 1:
The patent applies dynamics by transitioning from static force balance equations to dynamic equations of motion that explicitly account for time-varying bank angles. The estimation system incorporates acceleration sensors and gyro sensors to capture dynamic vehicle behavior during turning maneuvers, allowing the tire force estimation to adapt to changing operational conditions rather than relying on fixed balance relationships.
Solution Approach 2:
The patent changes the parameters used in the estimation model by introducing time-dependent bank angle parameters and their derivatives (angular velocity and angular acceleration). Instead of using constant gravitational and centrifugal force balances, the system uses dynamic parameters from sensors to model the vehicle's motion state, enabling accurate tire force estimation during transient phases when bank angle is changing.
2Device complexity
If static force balance equations are used for tire force estimation, then the estimation model is simple, but it cannot accurately capture forces during dynamic turning maneuvers
Solution Approach 1:
The patent transitions from static to dynamic estimation models by incorporating time-varying bank angle parameters and their rates of change. The system uses equations of motion that include acceleration and angular acceleration terms, allowing the model to capture dynamic forces during turning maneuvers while maintaining computational feasibility through structured mathematical relationships.
Solution Approach 2:
The patent introduces intermediary sensor measurements (acceleration sensor data and gyro sensor data) that mediate between the observable vehicle motion and the unobservable tire forces. These sensor readings serve as intermediaries that bridge the gap between measurable quantities and the forces to be estimated, enabling accurate dynamic tire force calculation without direct force 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
Improves the accuracy of tire force estimation in bank states by effectively accounting for changes in the vehicle's motion state and applied forces, enhancing precision during vehicle turning maneuvers.
Implementation Method 1
a value indicating a change over time of a motion state of the vehicle body in a vertical direction within a plane perpendicular to the forward-rearward axis, based on a value associated with a change over time of a bank angle of the vehicle body
Implementation Method 2
a change over time of a motion state of the vehicle body in a vertical direction within a plane perpendicular to the forward-rearward axis, based on a value associated with a change over time of a bank angle of the vehicle body
Implementation Method 3
estimate a vertical force applied in the vertical direction from the ground surface to the wheel, based on the change over time of the motion state of the vehicle body
Data Source
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AI summary
A tire force estimating device estimates tire forces which are forces applied from a ground surface to a wheel of a vehicle which turns in a bank state in which a vehicle body is tilted around a forward-rearward axis. The tire force estimating device includes a first tire force estimating section which estimates the force applied from the ground surface to the wheel, based on a change over time of a motion state of the vehicle body within a plane perpendicular to the forward-rearward axis.