Study On Steering Handling Stability Of Three Axle Emergency Rescue Vehicle With Active Suspension

This topic takes the three-axis heavy-duty high mobility emergency rescue vehicle with active suspension as the research object,to improve the complex coupling relationship between the multi axle steering system and the active suspension system,and to improve the steering performance of the vehicle,the coordination control of the multi axle steering system and the active suspension system is studied,which has important theoretical significance and practical application value.The topic of this project comes from the national key research and development plan:Research on the key technology of special chassis and suspension of high mobility emergency rescue vehicles(including fire vehicles)(project number: 2016YFC0802902).In order to improve the ride comfort and handling stability of the vehicle,the vehicle mathematical model considering the coupling relationship between suspension system and steering system is established,and the coordinated controller of suspension system and steering system is designed.Firstly,a nine degree of freedom active suspension model under B-level road is established,and the LQG controller of the active suspension actuator is designed.Secondly,optimize the steering mechanical structure,and analyze the stress of the key parts of the steering structure.Then,the steering proportion coefficients of the front axle and the middle and rear axle are calculated,and the three degree of freedom nonlinear steering dynamic model of the tire model considering the influence of the road adhesion coefficient is established,and the optimal feedback controller of the vehicle steering system is designed.Then,the coupling model of multi axle steering system and active suspension system is established,and the grey prediction fuzzy PID coordination controller is designed to improve the coupling relationship between vehicle steering system and active suspension system.Finally,based on the three-axis inertial control suspension system test platform,the test results show that: compared with the passive suspension three-axis rescue vehicle,the coordinated control active suspension three-axis rescue vehicle body mass center vertical acceleration root mean square decreased by24.0%,the roll angle acceleration root mean square decreased by 28.4%,the pitch angle acceleration root mean square decreased by 26.7%,the yaw angle acceleration root mean square decreased by 28.4% The root mean square of lateral acceleration decreased by30.8%.It is proved that the coordinated controller designed for the coupling problem of multi axis steering system and active suspension system has good control effect.