Backup Brake Control for Rear-Wheel Skid Threshold Adjustment
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Solution Overview
Problem
Conventional brake control systems for vehicles do not adequately address the issue of maintaining vehicle stability when the front wheels' braking system malfunctions, potentially leading to rear wheel locking and decreased stability.
Innovation Solution
A brake control apparatus with a backup brake system that switches to a secondary system when the primary system fails, incorporating a skid determination threshold setting section to adjust braking force based on the backup brake's information, ensuring deceleration and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If braking force of the rear wheels is increased to prevent front wheel locking when front braking system fails, then front wheel stability is improved, but rear wheels may lock and vehicle running stability deteriorates
Solution Approach 1:
The patent dynamically changes the skid determination threshold parameter based on the operational state of the backup brake. When the backup brake is activated, the threshold is adjusted to a higher value that accounts for the additional braking force applied, preventing false skid detection and unnecessary reduction of rear wheel braking force. This parameter adaptation resolves the contradiction by allowing aggressive rear wheel braking when needed while maintaining stability when the backup system is engaged.
Solution Approach 2:
The control system dynamically adjusts the skid determination threshold in real-time based on the backup brake state. The threshold is not fixed but changes according to the braking conditions and backup brake activation status. This dynamic adjustment enables the system to optimize rear wheel braking force under different failure scenarios, preventing both front wheel lockup and rear wheel lockup while maintaining vehicle stability.
2Ease of operation
If a fixed skid determination threshold is used for rear wheel braking control, then control simplicity is maintained, but accurate skid detection becomes difficult when backup brake is actuated
Solution Approach 1:
The patent implements a dual-threshold system where the skid determination threshold changes based on the backup brake state. A first threshold is used when the backup brake is inactive, and a second (higher) threshold is used when the backup brake is actuated. This parameter change approach maintains simple control logic while achieving accurate skid detection under varying braking conditions, as the threshold automatically adapts to the current system state.
Solution Approach 2:
The control strategy is segmented into different modes based on backup brake activation. The system divides the operating conditions into distinct segments: normal operation mode and backup brake activation mode. Each segment has its own appropriate threshold value, simplifying the control logic within each segment while improving overall detection accuracy across all operating conditions.
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 solution effectively ensures deceleration and maintains vehicle stability by adjusting braking force and skid determination thresholds, preventing rear wheel locking during primary system failures.
Implementation Method 1
a mechanical connection by a fluid pressure between a brake pedal and the electric hydraulic mechanism on the front wheel side including a pump, and a valve
Implementation Method 2
brake pads 26 are pressed against the brake discs BD to apply the braking force
Data Source
AI summary
An object of the present invention is to provide a brake control apparatus including a backup brake, which brake control apparatus makes it possible both to ensure deceleration, and to attain vehicle running stability.The present invention includes: a front-wheel-side braking mechanism 4 that includes a front-wheel-side electric hydraulic mechanism 6, and a hydraulic circuit system, and applies braking force to front wheels 2L, and 2R; a rear-wheel-side braking mechanism 5 that applies braking on a rear wheel side; a backup brake that is actuated in accordance with a switch to the hydraulic circuit system 15 when the front-wheel-side electric hydraulic mechanism 6 fails, and applies braking force to the front wheels 2R, and 2L; and a skid determination threshold setting section 43 that sets a skid determination threshold. When the backup brake is actuated, the skid determination threshold setting section 43 sets the skid determination threshold for the rear wheels 3L, and 3R on the basis of braking force information of the backup brake.