Vehicle Braking Force Distribution Control for Motion Stability
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Solution Overview
Problem
The existing vehicle braking systems face limitations in vehicle motion control during braking, as the margin of control braking force generated by the motor becomes insufficient due to increased regenerative braking demands, leading to unsatisfactory vehicle motion control.
Innovation Solution
A braking force control apparatus that dynamically adjusts the distribution between regenerative and mechanical braking forces based on vehicle state parameters and motor margin, ensuring sufficient control braking force for vehicle motion control by increasing mechanical braking when the motor's regenerative capacity is insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking force is increased to improve energy recovery, then energy recovery effect is improved, but the margin of control braking force for vehicle motion control decreases
Solution Approach 1:
The patent dynamically adjusts the distribution between regenerative braking force and friction braking force based on real-time vehicle motion states. When vehicle motion control requires larger margin, the system increases friction braking proportion; when energy recovery is prioritized, it increases regenerative braking proportion. This dynamic adjustment resolves the contradiction by making the braking force distribution adaptable to different operational requirements.
Solution Approach 2:
The system changes the parameter of braking force distribution ratio between regenerative and friction braking based on vehicle motion control needs. By adjusting this distribution parameter according to real-time conditions, the system optimizes both energy recovery and vehicle motion control performance simultaneously.
2Productivity
If regenerative braking force is increased to maximize energy recovery, then energy recovery efficiency is improved, but the margin of control braking force becomes insufficient for satisfactory vehicle motion control
Solution Approach 1:
The system continuously monitors vehicle motion control requirements and feedback-adjusts the braking force distribution. When vehicle motion control margin becomes insufficient, the system automatically increases friction braking proportion to restore adequate control margin, while still maintaining high energy recovery efficiency when conditions permit.
Solution Approach 2:
The braking force distribution is made dynamic rather than fixed, allowing the system to optimize energy recovery efficiency while maintaining sufficient vehicle motion control margin through real-time adjustment of the regenerative-to-friction braking ratio.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances vehicle motion control by maintaining or increasing the margin of control braking force, allowing for effective pitch, roll, yaw, and heave motion control, even under high regenerative braking conditions, thereby ensuring stable and comfortable vehicle operation.
Implementation Method 1
a motor (30) for transmitting a drive torque and a regenerative braking torque to a wheel, to thereby generate a braking/driving force on the wheel
Implementation Method 2
a mechanical brake device (40, 45) for applying a mechanical resistance to the wheel, to thereby generate a braking force on the wheel
Data Source
AI summary
In order to enable satisfactory vehicle motion control to be carried out while wheels (10) are being braked, on a vehicle in which each of the wheels (10) is braked by a regenerative braking force by a motor (30) and a friction braking force by a friction brake mechanism (40), a brake ECU (53) acquires at least one parameter out of a steering angle, a steering velocity, a lateral acceleration of a vehicle body, a yaw rate of the vehicle body, a sprung vertical acceleration, and an unsprung vertical acceleration, and when a magnitude of the parameter is more than a threshold, decreases a ratio of the regenerative braking force out of a driver-requested braking force, and increases a ratio of the friction braking force.