Vehicle Control Apparatus for Split Mu Road Hill-Hold
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Solution Overview
Problem
Existing vehicle control systems face challenges in preventing backward movement on split μ roads, where differing friction coefficients on either side of the vehicle can cause wheels to slip during braking force cancellation, leading to potential vehicle movement on slopes.
Innovation Solution
A control apparatus that captures front images to determine road surface conditions, adjusts braking force cancellation rates based on detected friction differences, and differentially controls braking forces between wheels to maintain traction and prevent slipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If braking force cancel control is executed rapidly, then the vehicle can quickly start moving, but the drive wheel may slip on split μ roads causing the vehicle to move backward
Solution Approach 1:
The braking force cancel control dynamically adjusts the rate of braking force reduction based on detected road conditions. On split μ roads, the control system reduces braking force at a slower rate compared to uniform μ roads, optimizing the balance between vehicle start speed and wheel traction stability.
Solution Approach 2:
The control system changes the parameter of braking force reduction rate according to the detected road surface friction characteristics. By identifying split μ conditions through image analysis and adjusting the braking force cancellation parameter accordingly, the system prevents wheel slip while maintaining effective vehicle启动.
2Loss of time
If the braking force is decreased rapidly to zero, then the control response is fast, but the drive wheel slips on roads with lower friction coefficient
Solution Approach 1:
The control system adjusts the braking force cancellation parameter based on road friction characteristics. For split μ roads identified through image processing, the system extends the cancellation time to prevent wheel slip, whereas for uniform μ roads, rapid cancellation is permitted.
Solution Approach 2:
The system uses feedback from the imaging device that detects road surface friction characteristics to continuously adjust the braking force cancellation rate. This closed-loop control ensures that the braking force is reduced at an appropriate rate to prevent wheel slip while maintaining fast response on suitable road surfaces.
3Stability of the object's composition
If hill-hold control maintains braking force, then the vehicle remains stationary on slope, but the vehicle cannot start moving forward
Solution Approach 1:
The control system dynamically transitions the braking force from a maintained constant level during hill-hold control to a gradually reduced level during braking force cancel control. This dynamic adjustment enables the vehicle to transition smoothly from a stationary stable state to a moving state without backward movement.
Solution Approach 2:
The system performs preliminary detection of road friction characteristics using the imaging device before executing braking force cancel control. This preliminary action allows the system to prepare an appropriate braking force reduction schedule that prevents wheel slip and backward movement from the outset of the vehicle start.
Data Source
AI summary
Provided is a control apparatus for a vehicle, the control apparatus being configured to determine a road surface μ state of a road in front of the vehicle based on an image of a front region of the vehicle, and change a magnitude of an amount of reduction in a braking force per unit time in accordance with the determined road surface μ state in braking force cancel control executed after hill-hold control