Cornering Brake Control With Driver-Intent Deceleration Correction
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Solution Overview
Problem
Existing vehicle control systems that enhance cornering performance by shifting load to the front wheels can cause driver discomfort due to unintended deceleration, especially when the accelerator or brake pedals are depressed, leading to an impression of dragging brakes or excessive deceleration.
Innovation Solution
A vehicle control system that calculates an additional deceleration based on vehicle state information and corrects it using a correction coefficient derived from the requested fore and aft acceleration, ensuring the deceleration feels natural to the driver by weakening it according to the driver's intended acceleration or deceleration, thereby improving cornering characteristics without discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional deceleration is applied to improve cornering performance by shifting load to front wheels, then cornering performance is improved, but driver discomfort increases due to unintended deceleration
Solution Approach 1:
The system dynamically adjusts the additional deceleration amount based on the requested fore and aft acceleration (Gxr) by changing the correction coefficient K. When Gxr is large (driver requests strong acceleration or deceleration), the correction coefficient reduces the additional deceleration to avoid discomfort. When Gxr is small, the full additional deceleration is applied to maximize cornering performance improvement.
2Reliability
If driving force reduction amount is increased to shift load to front wheels, then cornering performance is improved, but vehicle deceleration becomes excessive when brake pedal is depressed
Solution Approach 1:
The system uses feedback from the requested fore and aft acceleration (Gxr) to adjust the additional deceleration amount in real-time. The correction coefficient K is determined based on Gxr, creating a feedback loop that ensures the additional deceleration does not cause excessive vehicle deceleration when the driver is already requesting strong braking.
3Reliability
If driving force reduction amount is increased to shift load to front wheels, then cornering performance is improved, but brake dragging sensation occurs when accelerator pedal is depressed
Solution Approach 1:
The system changes the correction coefficient K based on the requested fore and aft acceleration Gxr. When the driver depresses the accelerator pedal significantly, Gxr becomes large and positive, causing the correction coefficient to reduce the additional deceleration amount, thereby eliminating the brake dragging sensation while maintaining cornering performance improvement.
Data Source
AI summary
The vehicle control system includes a braking force generating device (6, 22) configured to generate a braking force to shift a load of a vehicle to a side of front wheels thereof at an initial stage of a cornering, and a control device (31) configured to control the braking force generated by the braking force generating device. The control device calculates an additional deceleration (Gxadd) according to vehicle state information, calculates a requested fore and aft acceleration (Gxr) according to a requested fore and aft force (Fxr) for the vehicle, calculates a correction coefficient (K) for weakening the additional deceleration according to the requested fore and aft acceleration, corrects the additional deceleration by the correction coefficient, and calculates an additional braking force (Fbadd) to be generated by the braking force generating device according to the corrected additional deceleration.