Vehicle Turning Control via Slip Detection and Yaw Moment
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Solution Overview
Problem
Existing vehicle turning control systems face instability and tire force saturation issues due to delayed road surface frictional coefficient estimation, leading to potential vehicle instability and excessive tire slip on low-friction surfaces.
Innovation Solution
A vehicle turning control device that includes a yaw moment control system with a slip determination module to assess wheel angular velocity and vehicle speed, allowing for immediate stabilization by calculating control gains based on predetermined conditions, thereby optimizing braking/driving torque distribution without exceeding tire grip limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If road surface frictional coefficient is estimated using acceleration sensor, then vehicle attitude stabilization control can be performed, but response delay occurs until acceleration occurs after turning
Solution Approach 1:
The system performs preliminary determination of road surface state using wheel angular velocity and angular acceleration before actual turning acceleration occurs. The slip determination device calculates road surface frictional coefficient in advance by detecting wheel slip conditions, enabling the yaw moment control to be prepared and respond immediately when turning is initiated, eliminating the delay inherent in acceleration-based estimation methods.
2Reliability
If braking/driving force is applied by yaw moment control on low friction coefficient road surface, then vehicle stability is improved, but slip rate and wheel angular acceleration increase causing tire force saturation
Solution Approach 1:
The system continuously monitors wheel angular velocity and angular acceleration to detect slip conditions in real-time. When slip determination indicates approaching tire saturation limits, the yaw moment control device adjusts the braking/driving force accordingly, reducing the applied force to keep the vehicle stable without exceeding tire grip capacity. This closed-loop feedback prevents tire force saturation while maintaining vehicle stability on low-friction surfaces.
Solution Approach 2:
The control system dynamically adjusts the yaw moment control parameters based on the determined road surface state. When low friction coefficient is detected, the system modifies the braking/driving force magnitude and distribution to match the reduced tire capacity, preventing force application that would cause saturation. The control gain and force distribution are changed according to the detected slip conditions and road surface characteristics.
Data Source
AI summary
This vehicle turning control device controls the turning characteristic of a vehicle having braking/driving sources capable of independently controlling a braking/driving torque for each wheel. The vehicle turning control device includes a yaw moment control device for controlling a yaw moment occurring in the vehicle, and a slip determination device for determining a road surface state from the angular velocity and the angular acceleration of the wheel and the vehicle speed. The yaw moment control device includes a control gain calculator for calculating a control gain, a target yaw rate calculator for calculating a target yaw rate from the vehicle speed, the steering angle, and the control gain, and a yaw moment calculator for calculating the braking/driving torque for each wheel in accordance with the target yaw rate. The control gain calculator calculates the control gain on the basis of a determination result of the slip determination device.