Regenerative Braking Slip Control for Wheel Slippage Restraint
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Solution Overview
Problem
Existing braking control systems face challenges in maintaining regenerative electric power recovery while preventing excessive wheel slippage, particularly when slippage exceeds a set value.
Innovation Solution
A braking control device that individually controls friction braking force for each wheel and manages regenerative braking torque based on detected accelerator and brake pedal operations, wheel speeds, and vehicle speed. The device executes target slip control by adjusting the slip ratio of wheels and ensures that friction braking devices generate appropriate braking amounts during braking operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If coasting regenerative braking torque is reduced when slippage exceeds a set value, then wheel slippage is restrained, but the recovery amount of regenerative electric power decreases
Solution Approach 1:
The patent changes the control parameter from binary (reduce torque when slippage exceeds threshold) to continuous (adjust torque based on degree of slippage). The regenerative braking torque is adjusted proportionally to the slip ratio, allowing fine-grained control that maintains power recovery while preventing excessive slippage. This resolves the contradiction by transforming a harsh threshold-based reduction into a smooth parameter adjustment.
Solution Approach 2:
The patent implements a feedback control mechanism where the slip ratio is continuously calculated from wheel speed and vehicle speed, and this feedback is used to dynamically adjust the regenerative braking torque. The controller monitors the slip ratio in real-time and modifies the motor torque accordingly, creating a closed-loop system that balances slippage restraint with energy recovery. This feedback approach allows the system to respond adaptively rather than applying fixed reductions.
2Object-affected harmful factors
If target slip control is executed by controlling motor torque, then wheel slippage is restrained, but control complexity increases
Solution Approach 1:
The patent enables the braking control system to self-regulate by using the slip ratio calculation and feedback control to automatically adjust motor torque without requiring complex external intervention. The system serves itself by monitoring its own performance (slip ratio) and making necessary corrections (torque adjustment) autonomously. This self-service capability manages complexity by keeping the control logic internal and automated rather than requiring complex external control systems.
Solution Approach 2:
The patent makes the motor serve multiple functions: it acts as both a drive motor during acceleration and as a regenerative braking device during deceleration. The same motor and control system handle both propulsion and braking, reducing overall system complexity. The controller universally manages both acceleration and braking operations, eliminating the need for separate dedicated systems and simplifying the overall control architecture.
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 effectively maintains regenerative electric power recovery while restraining wheel slippage, ensuring stable braking performance and efficient energy regeneration.
Implementation Method 1
a regenerative braking device provided for a regenerative braking wheel of any one of a front wheel and a rear wheel
Implementation Method 2
a friction braking device that is enabled to individually control friction braking force to be applied to each of the front wheel and the rear wheel
Data Source
AI summary
A braking control device includes a derivation unit that derives the slip ratio of a wheel based on detected wheel speed and vehicle speed, a brake processor that determines braking amounts to be applied to a regenerative braking device and a friction braking device based on an accelerator operation amount and a braking operation amount, and a controller that controls the regenerative braking device and the friction braking device based on the determined braking amounts. When the slip ratio increases to a predetermined threshold value or more while the accelerator operation amount is decreasing, the controller executes target slip control for controlling torque of a motor of the regenerative braking device based on a predetermined target slip ratio to adjust the slip ratio, and when the target slip control is executed to perform the braking operation, the friction braking device generates a braking amount corresponding to the braking operation amount.