Wheel Speed Abnormality Detection for Anti-Skid Braking Control
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Solution Overview
Problem
Existing vehicle travel control systems fail to accurately determine wheel speed abnormalities, particularly due to electronic circuit failures, leading to incorrect anti-skid control decisions.
Innovation Solution
A vehicle travel control device that utilizes multiple wheel speed sensors to compare the wheel speeds of different wheels, determining abnormalities based on the relationship and rate of change, and adjusts estimated vehicle body speed to prevent incorrect anti-skid control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the estimated vehicle body speed is set based on the highest wheel speed, then the anti-skid control can respond quickly to wheel speed changes, but the estimated speed becomes excessively high when electronic circuit abnormalities occur in wheel speed sensors
Solution Approach 1:
The system continuously monitors the rate of increase of wheel speed and compares it against a reference value to detect abnormalities. When the rate exceeds the threshold, the system switches from using the highest wheel speed to using the middle wheel speed for estimating vehicle body speed, thereby preventing erroneous high speed estimates while maintaining quick response to normal wheel speed changes
Solution Approach 2:
The system changes the parameter used for speed estimation based on the detected condition. Under normal conditions, the highest wheel speed is used for quick response. When an abnormality is detected (rate of increase exceeds reference), the system switches to using the middle wheel speed, thereby adapting the estimation parameter to the current operational state to maintain reliability
2Device complexity
If the wheel speed difference threshold is used to detect abnormalities, then simple determination can be made, but unnecessary determinations occur during normal deceleration and turning operations
Solution Approach 1:
The system changes the detection parameter from static wheel speed difference to dynamic rate of increase of wheel speed. By monitoring how quickly the wheel speed changes rather than just the absolute difference, the system can distinguish between normal operational variations (deceleration, turning) and actual sensor abnormalities, thereby improving detection accuracy while maintaining computational simplicity
Data Source
AI summary
A vehicle travel control device includes a plurality of wheel speed detection devices and a control unit. A plurality of wheel speed detection devices detects the wheel speed of each of the plurality of wheels. The control unit performs vehicle travel control (anti-skid control) based on the wheel speed detected by the wheel speed detection device. The control unit determines whether the wheel speed of the first wheel is abnormal based on the relationship between the wheel speed of the first wheel with the highest wheel speed and the wheel speed of the second wheel with the second highest wheel speed. Abnormality determination is performed to determine whether there is. When the vehicle is braking, the control unit does not make an abnormality determination when the wheel speed increase rate of the first wheel is less than the increase rate reference value.