Wheel Slip Control Using Steering-Angle-Based Speed Estimation
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Solution Overview
Problem
Existing slip suppression control techniques for vehicles inaccurately calculate slip rates due to using the vehicle's body speed, which deviates from actual wheel speeds, leading to ineffective slip control and reduced accuracy in slip determination.
Innovation Solution
A control apparatus that acquires wheel speeds and steering angles to estimate vehicle speeds at each wheel position, using the minimum wheel speed and steering angle, allowing for precise slip rate control and determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If vehicle body speed is used to calculate slip rate, then the calculation is simple, but the accuracy of slip determination deteriorates
Solution Approach 1:
The patent divides the vehicle into multiple sections by calculating slip rates for each wheel individually rather than using a single body speed value. This segmentation allows each wheel's slip condition to be evaluated independently, improving accuracy while maintaining calculation simplicity through standardized formulas.
Solution Approach 2:
The patent applies local quality by estimating specific vehicle speeds at each wheel position based on steering angle and minimum wheel speed, rather than using a uniform body speed. This localized speed estimation accounts for the different linear velocities at different wheel positions during turning, thereby improving slip determination accuracy.
2Measurement precision
If wheel speeds are used to estimate vehicle speed at each wheel position, then slip rate control accuracy improves, but device complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating the relationship between steering angle and vehicle speed at each wheel position. The control apparatus stores these pre-computed values or relationships, allowing rapid lookup during slip control without performing complex real-time calculations, thus improving accuracy while minimizing added complexity.
Solution Approach 2:
The patent introduces steering angle as an intermediary parameter to estimate vehicle speeds at different wheel positions. Instead of directly measuring complex multi-point velocities, the system uses the easily measurable steering angle to infer position-specific speeds through geometric relationships, simplifying the control apparatus while improving slip rate accuracy.
Data Source
AI summary
A control apparatus to be applied to a vehicle includes an acquiring unit and an estimator. The acquiring unit is configured to acquire wheel speeds of respective wheels of the vehicle and a steering angle of the vehicle. The estimator is configured to estimate vehicle speeds at respective positions of the respective wheels, on the basis of a minimum wheel speed among the wheel speeds of the respective wheels and the steering angle.