Vehicle Braking Torque Slope Control for Split Road Stability
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Solution Overview
Problem
Existing vehicle braking control systems face a trade-off between directional stability and deceleration ability, particularly on split road surfaces and during sharp turns, where differences in friction coefficients between wheels can cause directional shifts and understeer, affecting braking performance.
Innovation Solution
A braking control device that adjusts the increase slope of braking torque for front wheels based on the deviation between intended and actual turning amounts, using sensors for steering angle and yaw rate to dynamically correct the increase slope, ensuring compatibility between directional stability and deceleration ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the pressure increase slope of the pressure increase control is decreased, then the directional stability is improved, but the deceleration ability of the vehicle is reduced
Solution Approach 1:
The patent applies dynamics by making the pressure increase slope adjustable rather than fixed. The control device dynamically changes the pressure increase slope based on vehicle operating conditions (straight travel, turning, split road surface detection) to optimize both directional stability and deceleration ability for each specific situation
Solution Approach 2:
The patent changes the parameter of pressure increase slope based on detected road conditions and vehicle state. When split road surface is detected, the pressure increase slope is reduced for the wheel on the high friction coefficient side to prevent excessive braking force that would cause directional instability, while maintaining adequate deceleration through coordinated control of other wheels
2Speed
If the pressure increase slope is increased, then the deceleration ability of the vehicle is increased, but the directional stability deteriorates
Solution Approach 1:
The patent applies local quality by applying different pressure increase slopes to different wheels based on their individual conditions. When split road surface is detected, the wheel on the high friction coefficient side receives a reduced pressure increase slope while other wheels maintain normal or adjusted slopes, creating localized optimization that preserves overall vehicle stability while maintaining deceleration capability
Solution Approach 2:
The control device changes the pressure increase slope parameter dynamically based on detected conditions. When turning is detected, the pressure increase slope is selectively adjusted for the outer wheel to prevent understeer while maintaining adequate deceleration. This parameter adaptation resolves the contradiction by matching the pressure increase rate to the specific mechanical conditions of each wheel
3Stability of the object's composition
If the pressure increase slope is decreased to suppress directional shift on split road, then the directional stability is improved, but the braking distance increases
Solution Approach 1:
The patent applies segmentation by independently controlling each wheel's braking force through individual pressure increase slopes. When split road surface is detected, the system segments the braking control by applying a reduced pressure increase slope only to the wheel on the high friction coefficient side while maintaining or adjusting slopes on other wheels, thereby preventing directional instability while preserving overall deceleration performance
Solution Approach 2:
The control device uses feedback from road surface condition detection and vehicle state monitoring to dynamically adjust pressure increase slopes. Based on feedback about which wheel is on high friction coefficient surface and the current vehicle state (straight or turning), the system selectively modifies pressure increase rates to maintain both stability and braking efficiency
4Productivity
If the pressure increase slope is increased to improve deceleration, then the braking distance is reduced, but the vehicle experiences understeer during sharp turns
Solution Approach 1:
The patent applies local quality by selectively adjusting the pressure increase slope for the outer wheel during turning operations. When a sharp turn is detected, the pressure increase slope for the outer wheel is reduced to prevent excessive braking force that would cause understeer, while other wheels maintain pressure increase rates optimized for deceleration, thereby preserving both directional stability and braking performance
Solution Approach 2:
The system dynamically adjusts pressure increase slopes based on real-time detection of turning state and road conditions. During sharp turns, the control device dynamically reduces the pressure increase slope for the outer wheel to prevent understeer while maintaining adequate deceleration through coordinated control of all wheels, resolving the contradiction between deceleration performance and directional stability
Data Source
AI summary
In the case that the road surface is determined to have different friction coefficients on the left and right wheels, this braking control device performs antiskid control for adjusting the increase slope of front wheel braking torque on the side with the higher friction coefficient. A steering angle sensor detects the steering angle, and a yaw rate sensor detects the yaw rate. The device calculates a reference turning amount on the basis of the steering angle, calculates an actual turning amount on the basis of the yaw rate, and sets the increase slope on the basis of the deviation between the reference turning amount and the actual turning amount. Also, if this deviation becomes larger, a correction is made such that the set increase slope becomes smaller. Further, if the deviation becomes smaller, a correction is made such that the set increase slope becomes larger.