Vehicle Control Device Adjusting Slippage Threshold for Different-Diameter Tires
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Solution Overview
Problem
Existing vehicle control systems face instability when a different-diameter tire is mounted on a drive wheel, leading to incorrect slippage detection and excessive torque down, as the rotation speed threshold is not adjusted for varying tire diameters, causing unnecessary slippage control and unstable vehicle behavior.
Innovation Solution
A vehicle control device with a slippage determination unit, a different-diameter determination unit, and a threshold adjuster that adjusts the rotation speed threshold based on the tire diameter ratio, ensuring accurate slippage detection and preventing excessive torque down by setting appropriate target rotation speeds for different-diameter tires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed rotation speed threshold is used for slippage determination, then the slippage detection is simple and quick, but the detection accuracy deteriorates when different-diameter tires are mounted
Solution Approach 1:
The patent applies dynamics by making the rotation speed threshold adjustable rather than fixed. The control device dynamically changes the threshold based on detected tire diameter, allowing the system to adapt to different operating conditions (different tire diameters) while maintaining accurate slippage detection without excessive complexity
Solution Approach 2:
The patent changes the parameter (rotation speed threshold) based on tire diameter. When a different-diameter tire is detected, the system calculates a corrected threshold by multiplying the standard threshold by the ratio of actual tire diameter to standard tire diameter, thereby maintaining detection accuracy across varying tire conditions
2Reliability
If the rotation speed threshold is not adjusted for different-diameter tires, then the control system remains simple, but vehicle behavior becomes unstable due to excessive torque down
Solution Approach 1:
The patent implements feedback by detecting the actual tire diameter and using this information to adjust the rotation speed threshold. The system continuously monitors tire diameter and dynamically adjusts the threshold to prevent false slippage detection, thereby maintaining vehicle stability without requiring excessive system complexity
Solution Approach 2:
The patent performs preliminary action by detecting tire diameter in advance and pre-calculating the appropriate threshold adjustment before slippage control is activated. This prevents false torque down actions from occurring in the first place, maintaining vehicle stability proactively rather than reactively
3Measurement precision
If slippage control is executed based on fixed threshold, then the control response is immediate, but unnecessary torque down occurs frequently with different-diameter tires
Solution Approach 1:
The patent changes the detection parameter (rotation speed threshold) based on tire diameter to improve measurement precision. By adjusting the threshold proportionally to the tire diameter ratio, the system accurately distinguishes between normal high rotation speeds of different-diameter tires and actual slippage conditions, preventing unnecessary control actions and improving overall control efficiency
Data Source
AI summary
A vehicle control device includes a slippage determination unit, a control unit, a different-diameter determination unit and a threshold adjuster. The slippage determination unit determines that a drive wheel is slipping when an index value that is correlated with a rotation speed of the drive wheel exceeds a threshold. The control unit controls a driving force of the drive wheel such that the index value matches a target value when it is determined that the drive wheel is slipping. The different-diameter determination unit determines whether a different-diameter tire that has a different diameter from a reference diameter is mounted on the drive wheel. The threshold adjuster adjusts a threshold on the basis of a ratio between a diameter of the tire mounted on the drive wheel and the reference diameter when it is determined that the different-diameter tire is mounted on the drive wheel.