Vehicle Stability Analysis under Extreme Operating Conditions Based on LQR Control

Area of Science:

• Vehicle dynamics and control systems engineering.
• Automotive safety and stability analysis.
• Advanced suspension system design.

Background:

• Vehicle stability and ride comfort degrade significantly under extreme operating conditions like high-speed driving, low-adhesion turns, and emergency maneuvers.
• Existing research primarily addresses conventional conditions, with limited focus on vehicle stability during extreme scenarios.
• Improving vehicle stability under extreme conditions is crucial for safety and performance.

Purpose of the Study:

• To investigate and enhance vehicle stability under extreme operating conditions using electromagnetic active suspension.
• To design and implement a linear quadratic regulator (LQR) controller for the electromagnetic active suspension system.
• To analyze the effectiveness of the proposed control strategy through simulations and real-world data validation.

Main Methods:

• Development of a seven degrees of freedom (7-DOF) vehicle dynamics model incorporating electromagnetic active suspension.
• Design of a linear quadratic regulator (LQR) controller tailored for the electromagnetic active suspension system.
• Creation of a joint MATLAB/CarSim simulation platform, with CarSim model validation against real vehicle test data.

Main Results:

• Significant reductions in root mean square (RMS) values for body droop acceleration (57.48%) and pitch angle acceleration (28.81%) under high-speed, uneven road conditions.
• Substantial improvements in RMS values for body droop acceleration (58.25%), pitch acceleration (55.41%), and roll angle acceleration (31.39%) during low-adhesion, double-shift maneuvers.
• Demonstrated enhancement of vehicle stability across various extreme operating scenarios.

Conclusions:

• Electromagnetic active suspension, when integrated with an LQR controller, effectively improves vehicle stability under extreme working conditions.
• The proposed system demonstrably reduces driving risks associated with challenging road and driving dynamics.
• The findings highlight the potential of advanced active suspension systems for enhancing overall vehicle safety and performance in demanding situations.