EV Brake Controller for ABS on Low-Resistance Roads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric vehicle controllers face challenges in maintaining running stability during anti-lock braking system (ABS) operation, particularly when road surface drag decreases, leading to delayed reduction in braking force and increased wheel lock amounts.
Innovation Solution
A controller for electric vehicles that executes anti-lock control by controlling hydraulic and regenerative braking forces, using speed feedback control to maintain wheel speed at a target speed while reducing hydraulic brake pressure when road surface resistance drops, thereby preventing wheel lock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the braking force of the regenerative brake is decreased to the decrease limit while the braking force of the hydraulic brake is maintained, then the regenerative braking force is maximized, but the reduction in braking force is delayed when road surface drag drops
Solution Approach 1:
The control device monitors wheel speed continuously and uses feedback control to adjust the regenerative braking force. When road surface drag decreases and wheel speed deviates from the target speed, the system detects this deviation and adjusts the braking force accordingly, ensuring running stability while maximizing regenerative braking.
Solution Approach 2:
The system dynamically adjusts the regenerative braking force based on real-time road surface conditions and wheel speed. Instead of maintaining a fixed braking force, the control device modifies the regenerative braking force in response to changing conditions, allowing timely reduction when road surface drag drops while still maximizing energy recovery during normal operation.
2Force
If the braking force of the hydraulic brake is maintained during anti-lock control, then the braking force of the regenerative brake can be maximized, but the wheel lock amount increases when road surface resistance decreases
Solution Approach 1:
The control device uses wheel speed feedback to monitor the actual braking effect and adjusts the regenerative braking force to prevent excessive wheel lock. When road surface resistance decreases and wheel lock amount increases, the system detects the deviation from target wheel speed and reduces the regenerative braking force accordingly, maintaining ease of wheel lock control while preserving overall braking force.
Solution Approach 2:
The system changes the regenerative braking force parameter in response to detected road surface conditions and wheel speed deviations. By adjusting this parameter dynamically, the system prevents excessive wheel lock when road surface resistance decreases while maintaining adequate braking force for safe operation.
3Measurement precision
If speed feedback control is used to control wheel speed to follow target speed, then wheel speed control precision is improved, but the system complexity increases
Solution Approach 1:
The control device implements speed feedback control by continuously monitoring wheel speed and comparing it to the target speed. This feedback mechanism improves wheel speed control precision by detecting deviations and adjusting the regenerative braking force accordingly. The feedback is achieved through existing sensors and control algorithms, minimizing additional system complexity.
Solution Approach 2:
The control device performs multiple functions using the same feedback control mechanism: it controls wheel speed during anti-lock braking, maximizes regenerative braking force, and adjusts to changing road surface conditions. This multi-functionality achieves high wheel speed control precision without proportionally increasing system complexity, as the same control system handles multiple objectives.
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 ensures timely reduction in braking force even when road surface drag decreases, thereby reducing wheel lock amounts and maintaining vehicle running stability, steering performance, and deceleration feel.
Implementation Method 1
a regenerative braking force by a motor
Implementation Method 2
a hydraulic braking force by a hydraulic brake device
Data Source
AI summary
A controller, which is for an electric vehicle for executing anti-lock control for suppressing a lock of a wheel by controlling a braking force using a hydraulic braking force by a hydraulic brake device and a regenerative braking force by a motor, controls to set a first state where the regenerative braking force is controlled by speed feedback control in which a hydraulic pressure of the hydraulic brake device, during execution of the anti-lock control, is set constant and a speed of the wheel is controlled to follow a target speed, determines whether a road surface resistance is lower than a predetermined value during the control to the first state, and reduces, when determining that the road surface resistance is lower than the predetermined value in the first state, the hydraulic pressure of the hydraulic brake device while controlling the regenerative braking force by the speed feedback control.