Wheel Slip Detection Using Tire-Corrected Slip Ratio
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Solution Overview
Problem
The estimation accuracy of a vehicle's slip ratio and vertical state is reduced due to slight slip occurrences when relying solely on wheel velocity changes, especially on varying road surfaces.
Innovation Solution
A slip state detection apparatus and suspension control apparatus that utilize tire characteristic-considered slip ratio determination and corrected slip ratio calculation, incorporating longitudinal acceleration and wheel rotational velocity to improve estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wheel velocity change amount is used to estimate vehicle body state, then the estimation process is simple, but the estimation accuracy deteriorates due to slight slip occurrences
Solution Approach 1:
The patent merges multiple detection approaches by combining the wheel velocity-based slip ratio estimation with a correction mechanism that uses longitudinal acceleration detection and tire characteristic considerations. This integration allows the system to maintain the simplicity of velocity-based estimation while adding accuracy through the correction process.
Solution Approach 2:
The patent introduces a correction mechanism as an intermediary element between the wheel velocity detection and the final slip ratio determination. This correction mechanism uses longitudinal acceleration detection and tire characteristic data to adjust the raw slip ratio estimation, thereby improving accuracy without completely replacing the original estimation method.
2Measurement precision
If tire characteristic-considered slip ratio and corrected slip ratio are calculated using multiple parameters, then the estimation accuracy improves, but the calculation complexity increases
Solution Approach 1:
The patent performs preliminary calculations by first determining the tire characteristic-considered slip ratio using longitudinal acceleration and tire characteristics, then separately calculating the wheel velocity-based slip ratio, and finally combining these results. This step-by-step preliminary action approach organizes the complex calculation process into manageable stages.
Solution Approach 2:
The patent segments the slip ratio calculation into distinct components: the tire characteristic-considered slip ratio determination, the wheel velocity-based slip ratio determination, and the correction process. This segmentation allows each component to be processed independently and then integrated, making the overall complex calculation more manageable and systematic.
Data Source
AI summary
A suspension control apparatus includes a slip state detection apparatus configured to detect a slip state of a wheel. The slip state detection apparatus includes a tire characteristic-considered slip ratio determination portion configured to determine a tire characteristic-considered slip ratio, which is a coefficient for correcting a slip ratio of the wheel determined based on a rotational velocity signal of the wheel, based on a longitudinal acceleration of a vehicle detected by a longitudinal acceleration detection portion and a tire characteristic; and a corrected slip ratio determination portion configured to determine a corrected slip ratio of the wheel by correcting the slip ratio of the wheel according to the tire characteristic-considered slip ratio.