AN ACTIVE ANTI-ROLL AIR SPRING SUSPENSION SYSTEM FOR A PASSENGER CAR
An active anti-roll air suspension system is developed on the basis of the original passive air springs. The key points of this active system focus on the actuator and the control strategy. In the actuator, two additional air volumes and a hydraulic or pneumatic supply element is integrated as a moveable element, which works to keep down the roll movement of car body. For the concept development, three concept models of the actuator are simulated. The hydropneumatic actuator is chosen because of its high velocity of movement, high precision of displacement und low impulse force on the actuator. For controlling the movement of the actuator, four discrete control strategies are compared. The Pulse Width Modulation (PWM) and PID controller is the best choice because of its small control error, high control speed and simple control loop. For the simulation of the whole car, a cosimulation model between DSH-plus and Matlab/Simulink is built. The simulation results show that the roll angle of the car is reduced from 3.5° with the passive suspension to 0° with the active suspension. In a simple validation test, a pneumatic cylinder is driven by a hydraulic cylinder. The test result shows that the roll angle of the car is reduced ca. 1.5° with the active actuator only on the front axle. So the active volume change of the air springs is an effective way to reduce the roll movement of the car. By car turning, this active anti-roll system acts to the better safety, stability and comfort for the car.
Author(s): Jun Zhang, Cheng Lin, Qiang Song
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