Research On Layered Control Strategy Of Active Suspension Based On Special Vehicle

As one of the core components of the vehicle chassis system,the suspension plays a role in transmitting and attenuating the force and torque between the body and the tire,alleviating and attenuating the impact caused by the external environment on the body,and its performance affects the smoothness and stability of the vehicle in the process of driving.Due to the limitation of its structural characteristics,the traditional passive suspension cannot guarantee good performance under all road conditions,and it often needs to make a compromise between smoothness and stability,which affects the performance of the suspension.However,there are many studies on the upper level of active suspension desired force control,but when uncertain parameters exist in the system,most of the research methods do not take different pavement excitation into account in the controller design,and the control target cannot be adjusted according to the change of pavement excitation.Therefore,the research on vehicle active suspension technology is of great significance and more and more people pay attention to it.In this paper,based on the national key research plan project "high mobile emergency rescue vehicles(including fire trucks)special chassis and suspension key technology research"(2016 yfc0802902),on the basis of reference related research literature at home and abroad,considering the effect of the incentive to the controller design and actuator output characteristic,in order to improve the riding comfort and handling stability of vehicles as the goal,the upper high and low pass filtering adaptive control and the lower force tracking adaptive robust control was studied.Firstly,according to the physical and dynamic characteristics of the three-axle heavy load vehicle,the appropriate state variables were selected,and the three-axle nine-degreeof-freedom mathematical model was established.Combining the characteristics of the vehicle and considering the lag and coherence between different wheel train,the road input model was deduced and established.The influence of vehicle suspension system on vehicle ride comfort and handling stability is analyzed.Secondly,the Backstepping active suspension control method,which adjusts the control target according to the road condition,was established.Through the research on active suspension control theory,Backstepping adaptive control strategy was adopted as the active suspension control strategy.Aiming at the defect that most controllers could not adjust the control target according to the road condition,the Backstepping control based on high-low pass filtering technology was researched and designed.Thirdly,based on the characteristics of the actuator modeling,the adaptive robust control method is studied to improve the control force tracking performance of the inner loop.The method of combining adaptive control and robust control is applied to optimize the uncertain parameters of the system by generating adaptive outputs related to response speed and robust outputs related to response precision.Improved force tracking control in the lower layer.Finally,the control effect of the controller designed in this paper was verified.In the Matlab/Simulink environment,the simulation models of passive suspension system and vehicle active suspension system were established respectively,and the simulation test was conducted with the road excitation as the input.The simulation results show that the designed controller has better ride comfort and handling stability than the passive suspension.