Research On Dynamics Response Of Kinetic Dynamic Suspension And Its Active Anti-roll Control

Suspension system is critical for vehicle roll stability,passing ability and ride-comfort.However,these above-mentioned aspects usually possess conflicting requirements on suspension parameters.It is quite difficult to reach a balance among these aspects,especially for SUV and other large size vehicles.This paper presents a Kinetic Dynamic Suspension(KDS)which is mainly designed for SUV and off-road vehicles.It can meet the demands of the three conflicting aspects simultaneously.The KDS provides larger anti-roll stiffness for high-speed cornering as well as lower anti-torsional torque for off road riding.The research content of this paper is arranged as bellow.The KDS structure and principle in different working conditions are analyzed,and based on that,the mathematic model of the hydraulic components and the modified stabilizer bar are built and then integrated into the KDS dynamic model.For the sake of handling stability simulation,a 14 degree-of-freedom vehicle dynamic model and magic tyre model are established.The above models compose the full vehicle model coupling with hydraulic model.The above models are established with MATLAB/Simulink simulation platform,then the key parameters of the system which used as the optimal parameters are determined after the parameter sensitivity analysis.Additionally,this paper proposed a novel parameter matching method based on performance requirement,take the anti-roll performance and the torsion-eliminate performance into consideration.The Isight tool is adopted to optimize the key parameters based on the system steady-state model.Based on the matching parameters and the full vehicle hydraulic coupling system model,the snake-shaped test,the twisted road and other conditions are designed to evaluating the handling stability,off-road trafficability and ride-comfort.The simulation result show that the KDS system can improve suspension roll stiffness,reduce the roll angle when the vehicle corners at high speeds,meanwhile,the torsion of body on off-road can be eliminated and the wheel ground adhesion and passing ability can be heightened without sacrificing the ride comfort.Besides,the matching parameters can satisfy the performance requirements of the vehicle.In this paper,a novel active KDS(AKDS)system is presented by replacing the two accumulators with actively controlled intermediate hydraulic cylinder.It can provide an active force acted on the piston rod of the intermediate cylinder to adjusting the anti-roll moment of the AKDS when the main motion mode of vehicle is roll mode.Conversely,there is no force acting on the piston rod of the intermediate cylinder when the main motion mode of vehicle is twisted,vertical and pitched.The dynamic model of the AKDS and the 3 degree-of-freedom model is established based on the analysis of the principle.The fuzzy controller is designed with taking the error and error rate between the roll angle and the reference value as the input variate.The piston rod active force is used as output variate.The fishhook and the snake-shaped test is adopted to verify the AKDS can provide a higher roll stiffness than passive KDS with a torsional bar which has a common or smaller torsional rigidity.