Vehicle Cornering Control Using Rough Road Deceleration Correction
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Solution Overview
Problem
Existing vehicle control systems that enhance cornering performance by shifting load to the front wheels fail to adapt to varying road conditions, leading to impaired ride quality on rough roads due to inadequate deceleration calculation and vibration issues.
Innovation Solution
A vehicle control system that includes a control device capable of calculating additional deceleration based on steering angle and wheel speed, with a rough road level calculation unit to correct control amounts, ensuring appropriate load shifting and minimizing discomfort during cornering maneuvers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If additional deceleration is generated to improve cornering performance by shifting load to front wheels, then cornering performance is improved, but ride quality deteriorates on rough roads due to excessive pitching and suspension bottoming out
Solution Approach 1:
The system dynamically adjusts the additional deceleration amount based on real-time road surface conditions. When rough roads are detected through wheel speed variations, the additional deceleration is reduced or suspended, preventing excessive pitching and suspension bottoming out. On smooth roads, full additional deceleration is applied to maximize cornering performance.
Solution Approach 2:
The control system changes the deceleration parameter adaptively based on road conditions. By monitoring wheel speed fluctuations and calculating rough road levels, the system modifies the deceleration amount parameter to match current road conditions, ensuring optimal balance between cornering performance and ride quality.
2Force
If deceleration control is applied without considering road surface conditions, then cornering performance is improved, but vehicle behavior becomes inconsistent across different road conditions
Solution Approach 1:
The system continuously monitors wheel speed variations and uses this feedback to determine road surface conditions. Based on the detected rough road level, the control system adjusts the deceleration command in real-time, ensuring consistent and appropriate vehicle behavior across varying road conditions rather than applying fixed deceleration control.
3Device complexity
If wheel speed is used directly for rough road level calculation, then calculation is simple, but cornering maneuver effects contaminate the rough road level measurement
Solution Approach 1:
The system extracts and removes the cornering maneuver component from the wheel speed signal before using it for rough road level calculation. By separating the cornering-induced wheel speed variations from the road surface condition indicators, the system achieves accurate rough road level measurement without overly complex processing.
Data Source
AI summary
A control device includes an additional deceleration calculation unit that calculates an additional deceleration (G×add) to be applied to the vehicle based on the steering angle, a target control amount calculation unit that calculates the control amount for the vehicle behavior changing device based on the additional deceleration, a rough road level calculation unit that calculates a rough road level of a road based on a wheel speed, and a control amount correction unit that corrects the control amount based on the rough road level, the rough road level calculation unit being configured to correct the wheel speed so as to remove a change thereof caused by the cornering maneuver of the vehicle, and to calculate the rough road level by using the corrected wheel speed.