Vehicle Stabilization via Rear Wheel Slip Angle Thresholds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle behavior stabilization systems are unable to accurately predict and quickly stabilize vehicle behavior under various conditions, leading to operator discomfort and potential instability due to reliance on inaccurate vehicle body slip angle measurements.
Innovation Solution
A vehicle behavior stabilization system that computes and applies a yaw moment based on rear wheel slip angle thresholds, dynamically adjusted by change rates and environmental factors like bank angle and lateral acceleration, using a feedback control mechanism to maintain cornering force within safe limits, thereby stabilizing the vehicle without time delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control is based on vehicle body slip angle and state variables, then yaw moment can be applied to prevent uncontrolled spinning, but the vehicle may not behave as expected under various conditions due to inaccurate slip angle measurements
Solution Approach 1:
The system performs preliminary stabilization control based on the rear wheel slip angle threshold before the vehicle reaches a critically unstable state. By monitoring the rear wheel slip angle and comparing it with the threshold value, the system activates yaw moment control in advance, preventing the vehicle from entering an unstable state rather than reacting after instability occurs.
Solution Approach 2:
The patent introduces the rear wheel slip angle as an intermediary parameter to bridge the gap between inaccurate vehicle body slip angle measurements and reliable stability assessment. The rear wheel slip angle serves as a more accurate indicator of actual vehicle stability, allowing the control system to make reliable decisions even when direct slip angle measurements are imprecise.
2Ease of operation
If yaw moment control is withheld until vehicle instability occurs, then vehicle behavior is allowed to remain natural under normal conditions, but the control system cannot stabilize the vehicle quickly enough once instability begins
Solution Approach 1:
The system performs preliminary stabilization control based on the rear wheel slip angle threshold before the vehicle reaches a critically unstable state. By monitoring the rear wheel slip angle and comparing it with the threshold value, the system activates yaw moment control in advance, preventing the vehicle from entering an unstable state rather than reacting after instability occurs.
Solution Approach 2:
The control system dynamically adjusts its intervention level based on the rear wheel slip angle magnitude. When the rear wheel slip angle exceeds the threshold, the system applies yaw moment control; when it returns below the threshold, the system deactivates control. This dynamic approach allows the vehicle to behave naturally during normal operation while enabling rapid stabilization when needed.
3Device complexity
If fixed threshold values are used for yaw moment control activation, then control logic is simple, but the system cannot adapt to different operating conditions and change rates
Solution Approach 1:
The threshold value is made dynamic by introducing a correction term based on the change rate of the rear wheel slip angle. The corrected threshold value = base threshold value - correction value, where the correction value is calculated from the change rate. This allows the threshold to adapt automatically to different operating conditions without complex control logic, enabling the system to respond appropriately to rapidly changing situations.
Data Source
AI summary
A vehicle behavior stabilization system includes a yaw moment applying device configured to apply a yaw moment to the vehicle, a vehicle behavior stabilization control unit configured to selectively control the yaw moment applying device in such a way to stabilize a vehicle behavior according to a computed rear wheel slip angle in relation to a start threshold value and an end threshold value, and a threshold value correcting unit configured to correct the start threshold value and the end threshold value according to a change rate of the computed rear wheel slip angle and/or a change rate of a computed vehicle body slip angle.