Brake Control Logic for Sudden Slope Stops
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional brake control systems fail to generate sufficient braking force when hydraulic pressure in the master cylinder does not reach the wheel cylinder due to sudden brake operations, leading to inadequate braking force, especially on slopes.
Innovation Solution
A brake control device that calculates a target current value for the motor based on hydraulic pressure and adjusts energization levels to ensure the necessary braking force is achieved by setting a hydraulic pressure threshold value corresponding to the road inclination angle and increasing motor energization when the hydraulic pressure falls below this threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the target braking force is generated by the electric braking force independently of the hydraulic braking force, then the braking force control is simplified, but an excessive braking force is generated
Solution Approach 1:
The control unit estimates the hydraulic braking force based on master cylinder hydraulic pressure and feeds this information back to adjust the electric braking force. The control unit calculates the required electric braking force by subtracting the estimated hydraulic braking force from the target braking force, ensuring the total braking force matches the target without excessive braking.
2Force
If the estimated hydraulic braking force is used to calculate electric braking force, then the total braking force can be controlled, but the necessary braking force cannot be realized when hydraulic pressure does not reach the wheel cylinder due to sudden brake operation
Solution Approach 1:
The control unit detects sudden brake operations by monitoring the time change amount of master cylinder hydraulic pressure. When a sudden operation is detected (time change amount exceeds predetermined value), the control unit preliminarily increases the electric braking force before the hydraulic pressure fully reaches the wheel cylinder. This preliminary action ensures the necessary braking force is available immediately on slopes without waiting for hydraulic pressure propagation.
3Adaptability or versatility
If the hydraulic pressure threshold value is set based on road inclination angle, then the braking force can be adjusted for different road conditions, but the control system complexity increases
Solution Approach 1:
The control unit changes the hydraulic pressure threshold value parameter based on the detected road inclination angle. When the vehicle is on a slope, the threshold value is increased to account for the additional braking force needed to prevent sliding. This parameter adjustment allows the system to adapt to different road conditions while maintaining a relatively simple control structure that builds upon the existing hydraulic pressure estimation framework.
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
The system effectively maintains the necessary braking force even during sudden brake operations, preventing vehicle sliding and ensuring safe stopping on slopes by dynamically adjusting the electric braking force in conjunction with hydraulic braking.
Implementation Method 1
an electric brake device that presses the braking member toward the member-to-be-braked by driving a motor to generate electric braking force
Implementation Method 2
a hydraulic brake device that presses a braking member by hydraulic pressure toward a member-to-be-braked that rotates integrally with a wheel of a vehicle to generate hydraulic braking force
Data Source
AI summary
A brake control device includes a control unit configured to calculate a target current value, which is a target current value to the motor, based on master cylinder hydraulic pressure, and reduce an energization level to the motor when an actual current value, which is an actual current value to the motor, reaches the target current value, set a hydraulic pressure threshold value, which is a threshold value of the master cylinder hydraulic pressure corresponding to a braking force necessary for the vehicle to stop based on an inclination angle of a road on which the vehicle is stopped, and calculate a time change amount of the master cylinder hydraulic pressure, and in a case where the time change amount exceeds a predetermined change amount, increase an energization level to the motor when the master cylinder hydraulic pressure subsequently becomes less than or equal to the hydraulic pressure threshold value.