Skid Detection for Four-Wheel Drive Vehicles
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Solution Overview
Problem
Existing skid detection methods for two-wheel drive vehicles are not applicable to four-wheel drive vehicles, particularly when two wheels on one side slip while the other wheels grip the road, making it difficult to accurately detect skids in four-wheel drive vehicles.
Innovation Solution
A skid detection apparatus that includes a front/rear wheel rotational speed detector, an actual rear right/left wheel speed ratio calculator, a grip-driving front/rear wheel slip ratio calculator, an actual front/rear wheel slip ratio calculator, and a skid determiner, which calculate and compare slip ratios to determine if a skid has occurred based on pre-defined characteristics and threshold values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing skid detection method for two-wheel drive vehicles is applied to four-wheel drive vehicles, then the detection method can be used, but it cannot accurately detect skids when two wheels on one side slip while the other wheels grip the road
Solution Approach 1:
The invention divides the wheel speed detection into separate front wheel speed and rear wheel speed measurements, and further segments the rear wheels into right and left wheels. By calculating the speed ratio between right and left rear wheels separately, the system can detect skids on individual sides of four-wheel drive vehicles, resolving the limitation of existing methods that only compare average front and rear wheel speeds.
2Device complexity
If simple average speed comparison is used for skid detection, then the detection system is simple, but it cannot detect skids when only one side of the vehicle experiences slippage
Solution Approach 1:
The invention applies local quality by specifically analyzing the speed ratio between right and left rear wheels rather than using a general average speed comparison. This localized measurement approach enables detection of asymmetric skid conditions where only one side of the vehicle slips, while maintaining relatively simple calculation procedures based on existing speed sensor data.
Data Source
AI summary
In an apparatus for detecting a skid occurred on a four-wheel drive vehicle having a prime mover and a transmission, an actual rear right/left wheel speed ratio between the rear right/left wheel speeds is calculated based on detected front and rear wheel rotational speeds, a front/rear wheel slip ratio during grip-driving is calculated by retrieving characteristics of a front/rear wheel slip ratio set with respect to a rear right/left wheel speed ratio using the calculated actual rear right/left wheel speed ratio, an actual front/rear wheel slip ratio is calculated based on the detected front wheel rotational speed and the rear wheel rotational speed, and occurrence of skid is then determined based on a difference between the calculated front/rear wheel slip ratio during grip-driving and the calculated actual front/rear wheel slip ratio.