Research On Design Method Of Linear Distuebance Obserber For Nonlinear Active Suspension Based On Siliding Mode Control

With cars being universal access,the quality of the suspension system also comes into play.Active suspensions have the advantages of strong adaptability to road conditions and good shock absorption effects,Having become a hot topic of research for vehicle suspension scholars.Now,the research on active suspension mainly focuses on the characteristics of the actuator and the control algorithm.Therefore,the study of control algorithms based on active suspension actuators has become one of the current research focuses on vehicle system dynamics.Taking into account the problem of existing active suspensions,such as the non-linear characteristics of the force,the uncertainty of the parameters and the nonideality actuator.To weaken the influence of these problems on the control effect,this paper designs a sliding mode control method with a disturbance observer reference skyhook model(LDO＿SMCRSM)method,and verify the effectiveness of its application in active suspension systems.The specific research work is as follows:Firstly,active suspension model with non-ideal actuators and uncertain parameters is constructed,which is mainly composed of the nonlinear active suspension,the nonlinear reference skyhook model(RSM)and the non-ideal actuator(NIA)model.Secondly,aiming at the traditional reference skyhook model sliding mode control(SMCRSM)algorithm,which does not fully consider the nonlinear characteristics of force,parameter uncertainty,and actuator nonideality,an easy-adjustable linear disturbance observer(LDO)is designed.It is used for estimation of uncertainties caused by nonlinear parameters,parameter uncertainties,and non-ideal actuators,then being in conjunction with SMC methods to build up a sliding mode control system with linear disturbance observer(LDO＿SMCS),and use Lyapunov direct method verifies the stability of the system.Thirdly,taking advantage of MATLAB/Simulink platform to model the overall simulation structure of the active suspension control system.Analysis of the effect of the skyhook damping coefficient(SDC)on the control effect have done,and accordingly raise the optimal SDC selection method.Further the anti-interference ability of LDO＿SMCS against uncertain sprung mass and non-ideal actuator disturbances is studied.Finally,simulation of the performance of a vehicle with an active suspension loaded with LDO＿SMCS under three typical vehicle driving conditions,bump roads,class C roads and rough roads is operated.The conclusion indicate that,juxtaposing vehicles with a conventional SMCRSM active suspension,active suspension vehicles with LDO＿SMCS in this paper has reduced the value of the root mean square(RMS)of sprung mass acceleration(SMA)in the three working conditions by 12 %,9.1%,10.7%,the RMS of tire dynamic load(TDL)reduced by 10%,8.7%,and increased by 5.4%,respectively,the RMS of suspension dynamic displacement(SSD)reduce by 23%,41.5%,5.5%.Revealing LDO＿SMCS in this paper has good control performance and strong robustness to road changes.