Vehicle Lateral Grip Control via Direct Force Calculation
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Solution Overview
Problem
Performance vehicles face integration errors and instability in vehicle models due to numerical drift, making it challenging to accurately determine yaw rate and lateral velocity without integration methods.
Innovation Solution
A method and system that determine the current lateral force on a tire, calculate desired yaw rate and lateral velocity for maximum yaw moment, and operate the vehicle at these parameters using a processor, which also determines maximum lateral force and yaw moment, and selects a performance mode based on tire capacity, employing a least squares method to avoid integration errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If integration methods are used to generate vehicle model parameters, then the vehicle model can be integrated over time to generate reference signals, but integration error is introduced that leads to numerical drift and instability
Solution Approach 1:
The patent extracts and eliminates the integration step from the vehicle model parameter generation process. Instead of integrating the vehicle model over time to generate reference signals, the system directly calculates current lateral force on tires and uses this to determine desired yaw rate and lateral velocity, thereby removing the source of integration errors and numerical drift while maintaining the ability to generate accurate reference signals
Solution Approach 2:
The patent replaces the mechanical integration process with a direct force-based calculation approach. By substituting the integration method with a system that directly determines lateral force and uses it to calculate yaw rate and lateral velocity, the system achieves numerical stability while maintaining accuracy in generating vehicle model parameters
2Force
If the vehicle operates at maximum tire capacity, then lateral grip is maximized for performance driving, but the system becomes highly sensitive to parameter accuracy and stability
Solution Approach 1:
The patent implements a feedback mechanism where the current lateral force on the tire is continuously determined and used to adjust the desired yaw rate and lateral velocity. This feedback loop ensures that the system operates at maximum tire capacity while maintaining parameter accuracy, as the real-time lateral force measurement provides continuous validation and adjustment of the control parameters
Solution Approach 2:
The patent dynamically changes control parameters based on the determined lateral force conditions. By adjusting desired yaw rate and lateral velocity as functions of the current lateral force state, the system adapts to varying tire capacity conditions while maintaining operation at the maximum grip limit, thereby managing the sensitivity to parameter accuracy through adaptive parameter transformation
Data Source
AI summary
A vehicle, and a method and system for operating the vehicle. The system includes a processor. The processor receives a driver input at the vehicle, determines a current lateral force on a tire of the vehicle for the driver input, determines a desired yaw rate and lateral velocity for the vehicle based on the current lateral force on the tire that operates the vehicle at a maximum yaw moment, and operates the vehicle at the desired yaw rate and lateral velocity.