Coordinated Control Of Vehicle Ride Comfort And Handing Stability Based On Active Suspension

Suspension is an important part of the vehicle structure.The performance of the suspension system has great influence on improving the ride comfort and handling stability of the vehicle.The active suspension controls the ride comfort and handling stability of the vehicle under different working conditions by adjusting the spring stiffness and damping characteristics.The active suspension greatly improves the driving performance of the automobile,and is the future direction of the development of the automobile chassis.Based on the theory and Application Research of active suspension system home and abroad,this paper aims at the effective coordination of vehicle ride comfort and handling stability under different working conditions.The control method of electronically controlled air suspension system with adjustable stiffness air spring and damping variable damper is studied.The main contents are as follows:(1)The structure and parameter characteristics of air spring and shock absorber are analyzed and the control modes of air spring and shock absorber under different working conditions are designed.The characteristics of the air spring stiffness and the continuous change of shock absorber damping are analyzed theoretically and experimentally.The control modes of air spring and shock absorber are designed according to the running condition of automobile and the characteristics of air spring and shock absorber.(2)The whole vehicle dynamics model of electronically controlled air suspension is established and a comprehensive evaluation system for ride comfort and handling stability of car is established.Firstly,the real driving environment is simulated,and the road excitation model and tire model are set up.Secondly a passive suspension model of two degrees of freedom is established and simulated in Simulink.The two degree of freedom vibration model of the active suspension and the nine degree of freedom model considering the vibration characteristics and handling stability of the vehicle are established.Based on the influence of suspension system on vehicle ride comfort and handling stability,a comprehensive evaluation system of ride comfort and handling stability of electronically controlled air suspension is put forward.(3)PID control model of electronically controlled air suspension is established.Based on the two degree of freedom active suspension model,the PID control system of active suspension is designed and simulated.The simulation results show that the PID controlled active suspension system reduces both vertical acceleration and suspension stroke,and vehicle ride comfort is improved.The tire dynamic load increased slightly but within the controllable range.(4)A coordinated control model of vehicle ride comfort and handling stability based on PID control and fuzzy control is established.A coordinated control method of vehicle ride comfort and handling stability based on PID control and fuzzy control is proposed to improve ride comfort and steering stability during cornering.The coordinated control of ride comfort and handling stability was simulated and verified in the 9 DOF vehicle model.The results show that the vehicle with coordinated control of active suspension has improved vehicle ride comfort and handling stability.