Vehicle Braking Force Control Optimizing Yaw Moment Ratio
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Solution Overview
Problem
Conventional vehicle braking/driving force control apparatuses are limited in generating braking/driving force and yaw moment, failing to achieve required levels within the range of forces that can be generated by the wheels, which affects vehicle stability and performance.
Innovation Solution
A vehicle braking/driving force control apparatus that includes means to apply braking/driving forces to wheels, detect occupant operations, calculate target braking/driving force and yaw moment, and control each wheel's force to maximize the ratio of braking/driving force and yaw moment within the achievable range, using independent control of each wheel and variable distribution of driving forces between wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the braking/driving force control is performed through the control of the braking/driving forces of the wheels, then the vehicle braking/driving force and yaw moment can be controlled, but the required braking/driving force and yaw moment cannot be achieved when they exceed the attainable values by wheel control
Solution Approach 1:
The control means changes the control parameters by calculating target braking/driving forces for each wheel that satisfy both the required vehicle braking/driving force and yaw moment while respecting wheel force limitations. When the required values cannot be achieved, it adjusts the target values to the maximum attainable values within the wheel force constraints, thereby optimizing the parameter distribution to resolve the contradiction between required force and achievable force.
2Power
If the target braking/driving force and yaw moment are calculated based on occupant operation, then the required vehicle performance can be determined, but the target values cannot be achieved when they exceed wheel capability
Solution Approach 1:
The control means incorporates feedback by continuously monitoring the attainable braking/driving forces of the wheels and adjusting the target braking/driving forces accordingly. When the calculated target values based on occupant operation exceed wheel capabilities, the system feeds back the maximum attainable values that maintain the required force-yaw moment ratio, ensuring the targets are achievable while preserving the intended vehicle behavior.
3Stability of the object's composition
If the braking/driving forces of wheels are controlled to achieve required vehicle braking/driving force and yaw moment, then vehicle stability can be enhanced, but the control becomes complex when optimization is needed
Solution Approach 1:
The control means employs dynamic adjustment by calculating optimal target braking/driving forces for each wheel based on real-time conditions. It dynamically determines the distribution of braking/driving forces among wheels to achieve the required vehicle braking/driving force and yaw moment while maintaining stability. When optimization is needed, it adaptively adjusts the target values to the maximum attainable values within constraints, providing a dynamic solution that balances stability enhancement with controlled complexity.
Data Source
AI summary
In a braking/driving force control apparatus, a vehicle target braking/driving force and a vehicle target yaw moment through the control of braking/driving forces of wheels are calculated, and when the target braking/driving force and the target yaw moment cannot be achieved through the control of the braking/driving forces of the wheels, the vehicle target braking/driving force after the modification and the vehicle target yaw moment after the modification are calculated such that, within the range where the ratio of the vehicle target braking/driving force after the modification and the vehicle target yaw moment after the modification coincides with the ratio of the target braking/driving force and the target yaw moment, the vehicle braking/driving force and the vehicle yaw moment by the target braking/driving forces of the wheels take the greatest values.