Vehicle Controller Lateral Slip Threshold Based on Wheel Forces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle control systems fail to initiate lateral slip suppression at a proper timing due to reliance on vehicle speed rather than the gripping state of the drive wheel, leading to potential improper initiation of longitudinal force control.
Innovation Solution
A vehicle controller that calculates lateral slip amounts and decides a lateral slip limit threshold based on both longitudinal force and normal force applied to the target wheel, allowing for timely initiation of lateral slip suppressing control, including adjustments to longitudinal force and distributed load, to prevent side slipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the threshold is decided based on vehicle speed, then the control system is simple to operate, but the lateral slip suppressing control may not be initiated at a proper timing because vehicle speed does not always correspond to the gripping state of the drive wheel
Solution Approach 1:
The patent changes the basis for determining the threshold from vehicle speed to wheel slip ratio. The lateral slip limit threshold is now decided based on at least one of the longitudinal force or normal force applied to the target wheel, which directly reflects the gripping state between the drive wheel and ground surface. This parameter change ensures that control initiation timing accurately corresponds to actual traction conditions rather than just vehicle speed.
2Reliability
If the lateral slip limit threshold is decided based on both longitudinal force and normal force, then the control initiation timing is more accurate, but the calculation complexity increases
Solution Approach 1:
The patent calculates the longitudinal force and normal force in advance as basis data for threshold determination. By preparing these force parameters beforehand through preliminary calculations based on vehicle dynamics models and sensor data, the system can quickly determine the lateral slip limit threshold without complex real-time computations, thus achieving accurate control timing with manageable calculation complexity.
3Reliability
If lateral slip suppressing control is performed during constant-speed traveling, then all potential lateral slip situations are covered, but unnecessary control actions increase
Solution Approach 1:
The patent makes the lateral slip suppressing control dynamic by conditioning it on acceleration or deceleration states. The control is selectively activated only when the vehicle is accelerating or decelerating, which are the conditions where lateral slip is most likely to occur. During constant-speed traveling, the control is not activated, avoiding unnecessary energy consumption while still covering all critical lateral slip situations.
Data Source
AI summary
A vehicle controller calculates a lateral slip amount indicating a degree to which a target wheel to be controlled which is a front wheel or a rear wheel of a vehicle is slipping in a rightward and leftward direction on a ground surface; performs a lateral slip suppressing control including at least one of a control for reducing an absolute value of a command value of a longitudinal force in a forward and rearward direction which is applied from the ground surface to the target wheel and a control for increasing a distributed load applied to the target wheel, in a case where it is determined that the lateral slip amount is greater than a lateral slip limit threshold; and decides the lateral slip limit threshold based on at least one of the longitudinal force and a normal force applied to the target wheel.