Vehicle Brake Control System Wheel Lock Detection
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Solution Overview
Problem
Existing brake control systems face challenges in accurately determining when a wheel is likely to lock during braking, particularly due to low calculation accuracy of slip ratios and indirect reliance on braking force parameters, which can lead to improper timing for initiating anti-lock brake control (ABS) in motorcycles.
Innovation Solution
A brake control system that directly detects a wheel's likelihood of locking by monitoring the decrease rate of wheel speed and using a predetermined threshold, independent of wheel speed calculations, allowing for more accurate and timely initiation of ABS control, and adjusting thresholds based on driving state and road conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If slip ratio is calculated based on difference between front and rear wheel speeds, then ABS control initiation timing can be determined, but calculation accuracy deteriorates when rear wheel is spaced apart from road surface during rapid deceleration
Solution Approach 1:
The patent extracts the problematic element (rear wheel speed measurement) from the slip ratio calculation when the rear wheel is spaced apart from the road surface. Instead of using the unreliable rear wheel speed, the system switches to using only front wheel speed information, thereby eliminating the source of calculation error while maintaining the ability to detect wheel lock conditions.
Solution Approach 2:
The patent changes the parameters used for slip ratio calculation based on detected wheel state. When the rear wheel is determined to be spaced apart from the road surface, the system transitions from using both front and rear wheel speeds to using alternative parameters that do not depend on the unreliable rear wheel speed measurement, thus maintaining calculation accuracy under varying conditions.
2Device complexity
If ABS control is initiated based on magnitude of braking force, then control can be simplified, but determination accuracy deteriorates because braking force only indirectly indicates wheel lock likelihood
Solution Approach 1:
The patent replaces the indirect mechanical parameter (braking force magnitude) with a direct kinematic parameter (wheel speed decrease rate). This substitution allows for more accurate wheel lock detection by directly measuring the effect of braking (wheel deceleration) rather than inferring it from the applied force, thereby improving measurement precision without significantly increasing system complexity.
Data Source
AI summary
A brake control system in a vehicle which executes anti-lock brake control for controlling a braking force applied to a wheel to prevent the wheel from being locked during braking of the vehicle is provided. The brake control system includes an initiation determiner section for determining whether or not an initiation condition used to initiate the anti-lock brake control is met the initiation condition including a condition in which a decrease rate of a wheel speed which is a rotational speed of the wheel is not less than a predetermined threshold; and a brake control section for initiating control of the braking force applied to the wheel in the anti-lock brake control, if the initiation determiner section determines that the initiation condition is met.