Regenerative Braking Control Under ABS for Independent Wheel Motors
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Solution Overview
Problem
Existing regenerative braking systems in high-performance vehicles are limited by fixed energy regeneration distribution, leading to inefficiencies and instability, especially during emergency braking, which affects performance and energy availability.
Innovation Solution
A control method for regenerative braking in vehicles with independent electric motors on each wheel, dynamically adjusting hydraulic and electric braking torques based on grip factor and vertical load to optimize energy regeneration and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is activated during emergency braking, then energy regeneration is improved, but vehicle stability deteriorates due to ABS operation
Solution Approach 1:
The system dynamically adjusts the distribution of braking torque between hydraulic and electric motors based on real-time conditions. During emergency braking with ABS operation, the control unit modulates the electric braking torque to complement hydraulic braking, optimizing both energy regeneration and vehicle stability through continuous adaptation to changing braking conditions
Solution Approach 2:
The control unit changes the parameter of electric braking torque magnitude based on ABS operation status. When ABS is detected to be operating, the system adjusts the electric motor torque contribution to maintain optimal braking force distribution, thereby improving energy recovery while preserving stability control
2Device complexity
If fixed division of braking between front and rear axles is used, then system complexity is reduced, but energy regeneration potential is limited
Solution Approach 1:
The braking control system is segmented into independent controllable units for front and rear axles, each with its own electric motor. This allows independent optimization of braking torque distribution on each axle based on local conditions (wheel speed, grip level, vertical load), maximizing energy regeneration potential while maintaining manageable system complexity through modular architecture
Solution Approach 2:
The system dynamically redistributes braking torque between front and rear axles based on real-time vehicle conditions such as deceleration rate, wheel slip, and grip variations. This dynamic allocation optimizes energy recovery by engaging the axle with better grip conditions for regenerative braking, rather than using fixed division
3Stability of the object's composition
If regenerative braking is disabled during ABS conditions, then vehicle stability is maintained, but energy regeneration is lost
Solution Approach 1:
The control unit acts as an intermediary that coordinates between the ABS hydraulic system and electric motor regenerative braking. It monitors ABS operation status and modulates electric torque contribution accordingly, allowing regenerative braking to operate in conjunction with ABS rather than being completely disabled, thus recovering energy while maintaining stability
Solution Approach 2:
The system changes the operating parameter of electric braking torque based on ABS detection. When ABS is active, the control unit adjusts the electric motor torque to work in conjunction with hydraulic braking, optimizing the combined braking force to maintain stability while enabling continuous energy regeneration
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
Enhances energy regeneration and vehicle performance by maximizing available energy for acceleration, while maintaining stability during dynamic braking conditions.
Implementation Method 1
the energy regenerated in this manner by the aforesaid electric motor is reintroduced into the high-voltage battery
Implementation Method 2
a part of the braking action, normally allocated to the effect of friction between a brake pad placed in contact with a brake disc
Data Source
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AI summary
A control method for regenerative braking of a road vehicle comprising the steps, for each driving wheel (4, 5), of: estimating a grip factor (G); defining or collecting a vertical load (Fz); computing a value of a maximum braking capacity (MRT) depending on the grip factor (G) and the vertical load (Fz); controlling a braking system (13), following a request for braking, so as to actuate a hydraulic unit (18) to exert a first braking torque (mBT) and so as to actuate in regenerative electric braking each wheel at least according to the respective maximum braking capacity (MRT) value and in particular the first braking torque (mBT); and modulating the first braking torque (mBT) and/or the second braking torque (eBT) so that their sum is equal to or less than the respective maximum braking capacity (MRT) value.