Research On The Coordinated Control Of Vehicle Composite Air Suspension

In order to effectively improve the dynamic performance of vehicle suspension under different driving conditions,based on the structural characteristics of air suspension and the working principle of electromagnetic suspension actuator,this paper designs a composite air suspension actuator structure based on air spring and ball screw,which can give full play to the advantages of adjustable height of air suspension to adapt to different driving conditions,and can also be used in different driving conditions In order to achieve the control goal of different vehicle height,the damping matching control is carried out at the height.Based on the analysis of the structure and working principle of the composite air suspension,the two degree of freedom dynamic model,the air spring model,the ball screw model and the road roughness model of the suspension are established respectively.A ccording to the characteristics of the composite air suspension,the height mode and the damping matching control target of the vehicle body are analyzed.The PID control,fuzzy control and fuzzy PID control based on the solenoid valve are designed to adjust the body height,and the MATLAB software is used to model and analyze;the ideal ball screw damping matching reference current obtained by the hybrid ceiling control strategy is analyzed to control the damping matching effect of the composite air suspension under various height modes;the multi-mode of the composite air suspension system is designed The root mean square values of the dynamic performance indexes of the coordinated control strategy under the mixed condition are simulated and analyzed.Finally,the physical prototype of the composite air suspension is trial manufactured and a test bench is built to test the effectiveness of the composite air suspension.The simulation results show that the vehicle body height adjustment can basically eliminate the oscillation phenomenon in the process of vehicle body height control under the fuzzy PID control,and the vehicle body height change value can keep stable after accurately reaching the target height change value;in each mode,the damping matching control can achieve different control objectives.Under the mixed condition,the RMS value of spring load acceleration,suspension dynamic deflection,tire dynamic load and suspension dynamic performance are reduced by 20.68%,16.06%and 19.22%respectively before and after the multi-mode coordinated control of composite air suspension.The test results show that the opening and closing of the control solenoid valve can effectively achieve the air spring inflation and deflation,and then adjust the body height;under the condition of random road spectrum input,compared with the traditional air suspension,the root mean square value of the spring loaded mass acceleration of the composite air suspension system is reduced by 14.74%,which verifies the effectiveness of the composite air suspension system.