Rear-Wheel Regenerative Braking Control for Slip-Stable Deceleration
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Solution Overview
Problem
Regenerative braking in vehicles with rear wheel motors leads to vehicle instability on slippery roads due to over-braking and unintended deceleration, affecting the driver's deceleration feeling.
Innovation Solution
A braking system that compensates for coast regeneration torque reduction using hydraulic braking based on rear wheel slip, maintaining consistent vehicle deceleration and stability by controlling the hydraulic braking device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is performed by the driving motor during braking, then fuel efficiency is improved through energy recovery, but vehicle stability deteriorates on slippery road surfaces due to over-braking of the rear wheel
Solution Approach 1:
The patent combines regenerative braking and hydraulic braking into a unified braking system that operates cooperatively. The controller integrates both braking mechanisms to achieve stable braking performance, using hydraulic braking to compensate for regenerative braking limitations on slippery surfaces while maintaining energy recovery benefits
Solution Approach 2:
The system dynamically adjusts the regenerative braking torque based on detected wheel slip conditions. When slip is detected, the controller reduces or deactivates regenerative braking torque to prevent over-braking, thereby maintaining vehicle stability while still allowing regenerative braking to operate under normal conditions
2Stability of the object's composition
If the coast regeneration torque is reduced to maintain vehicle stability during slip control, then vehicle stability is improved, but the driver experiences unintended deceleration
Solution Approach 1:
The hydraulic braking device serves as an intermediary to compensate for the reduction in regenerative braking torque. When regenerative braking is reduced to prevent wheel slip, the hydraulic braking system provides additional braking force to maintain the overall deceleration level, ensuring the driver experiences smooth and intended deceleration
Solution Approach 2:
The system applies different braking strategies to different wheels based on local conditions. The rear wheel receives controlled regenerative braking with slip prevention, while the front wheel receives hydraulic braking to maintain overall vehicle deceleration and stability
3Force
If regenerative braking amount is increased to satisfy driver's required braking amount, then braking performance is improved, but wheel slip occurs at the rear wheel on slippery surfaces
Solution Approach 1:
The system continuously monitors wheel slip conditions and provides feedback to the controller. When wheel slip is detected at the rear wheel, the controller adjusts the regenerative braking torque in real-time to prevent further slip, thereby maintaining reliable braking performance without causing wheel slip
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
Improves vehicle stability and driver deceleration feeling by consistently maintaining deceleration through hydraulic braking compensation during regenerative braking.
Implementation Method 1
the driving motor operates as a generator to recover inertial energy
Implementation Method 2
a hydraulic braking device configured to supply a hydraulic pressure to front and rear wheels
Data Source
AI summary
Disclosed herein is a braking system including a hydraulic braking device configured to supply a hydraulic pressure to front and rear wheels of a vehicle to perform braking of the vehicle and a controller configured to control the hydraulic braking device to compensate for a coast regeneration torque reduction amount, which is applied to a driving motor driving the rear wheels, using a hydraulic braking amount based on a slip rate of the rear wheel being greater than or equal to a preset threshold value during a regenerative braking by the driving motor.