| As people pay more and more attention to the safety and comfort of the vehicle,suspension becomes the key to improve the ride comfort,handling stability and trafficability of full vehicle.Due to its nonlinear stiffness and damping characteristics,the vehicle performance can be improved by its reasonable design.In addition,the unit mass energy storage of hydro-pneumatic suspension is large and the damping valve is built in,which is conducive to reducing the weight and size of suspension and facilitating the layout of the whole vehicle.These reasons make hydro-pneumatic suspension have great potential in application and become the direction of future development.Active hydro-pneumatic suspension can significantly improve the performance of vehicles,but its development is limited by its expensive cost and complex executive components.The performance of the valve controlled semi-active hydro pneumatic suspension depends on the accuracy of the actual solenoid valve control,and its ability to improve vehicle performance is limited.Therefore,on the premise of improving vehicle performance,it is the goal of pursuit to seek a kind of hydro-pneumatic suspension with low cost,simple and reliable structure.A class of integrated interconnected hydro-pneumatic suspension vehicles with anti-pitch and roll,by eliminating the external accumulator,through the pipeline to achieve the interconnection of hydro-pneumatic suspension,simple and reliable structure and low cost,its research has theoretical research value and engineering application significance.Some related research work has been carried out on integrated interconnected hydro-pneumatic suspension vehicles with anti-pitch and roll.The analysis of interconnection configuration mostly focuses on one or several configurations directly,and there is no systematic explanation for the integrated interconnected hydro-pneumatic suspension combination configuration.The road surface used in the ride comfort study is mostly a measured road surface,the vehicle speed is single,the evaluation index selection is incomplete,and the lack of analysis of roll acceleration makes the evaluation result analysis incomplete.Ride improvement studies only analyze the parameters,stiffness,and damping,and do not reveal the relationship between parameters and evaluation indicators.The research needs to be further studied.In view of the problems existing in the research of integrated interconnected hydro-pneumatic suspension vehicles,this article studies the integrated interconnection hydro-pneumatic suspension,the main research content and results are as follows:(1)This paper discusses the combination of integrated interconnected hydro-pneumatic suspension,discusses the advantages of integrated hydro-pneumatic suspension,and explains the basic configuration of integrated hydro-pneumatic suspension.Aiming at the problem of plane interconnection combination,possible plane interconnection combination configurations are listed.Through the analysis of left and right single wire interconnection,left and right double wire interconnection combination,left and right three wire interconnection combination,and four wire interconnection combination,a reasonable plane configuration of integrated interconnected hydro pneumatic suspension is determined.Aiming at the problem of spatial interconnection combination,the basic principle of interconnection combination is put forward.Taking the spatial interconnection of four pipelines as the research object,the situation of two interconnections and three symmetrical interconnections is emphatically discussed,and three spatial configurations of integrated interconnection suspension with certain anti pitch and roll functions are determined.(2)Two kinds of plane configuration of integrated independent hydro-pneumatic suspension and integrated interconnected hydro-pneumatic suspension vehicle are theoretically modeled.Through the study of the relationship between flow and motion,damping hole pressure and flow,pipeline pressure and flow,and gas pressure,the explicit mathematical expression of dynamic force of integrated independent hydro-pneumatic suspension and integrated interconnected hydro-pneumatic suspension is derived.For the two plane configurations of integrated hydro-pneumatic suspension vehicle,the vehicle dynamics model is established by using the four degree of freedom vehicle plane model,and the corresponding simulation model is developed by using Matlab/Simulink.The time-domain model of filtering white noise and the time-domain model of pulse road excitation of front and rear wheels are established.Two types of evaluation indexes for the ride comfort of random roads and pulse roads are given for the plane model.Aiming at the B-level road,C-level road,D-level road and pulse road,the ride comfort simulation and comparative analysis of two kinds of plane configuration of integrated hydro pneumatic suspension vehicle under different speeds are carried out,and the anti pitching effect of integrated interconnected hydro-pneumatic suspension vehicle is illustrated.(3)In order to illustrate the anti roll effect of integrated interconnected hydro-pneumaticsuspension,the theoretical modeling of integrated independent hydro-pneumatic suspension and three spatial configurations of integrated interconnected hydro-pneumatic suspension is carried out.The implicit mathematical expression of dynamic force of four integrated hydro-pneumatic suspension spatial configurations is derived through the matrix representation of motion,flow,pressure and dynamic force of suspension.For the four space configurations of integrated hydro-pneumatic suspension vehicle,the vehicle dynamics model is established by using the 7-DOF vehicle space model,and the corresponding simulation model is developed by using Matlab/Simulink.The filtering white noise time-domain model and the pulse road excitation time-domain model of the road random excitation of the four wheels are established by the correlation between the left and right wheels and the time-delay of the front and rear wheels,according to the spatial model,two kinds of evaluation indexes of random pavement and impulse pavement are given.Aiming at the B-level road,C-level road,D-level road and pulse road,the ride comfort simulation and comparative analysis of four spatial configurations of integrated hydro-pneumatic suspension vehicle under different speeds are carried out,and the anti pitching and anti-roll effects of the spatial configuration of integrated interconnected hydro-pneumatic suspension vehicle are illustrated.(4)Comparison of smoothness of three spatial configurations of integrated interconnected hydro-pneumatic suspension.The third spatial configuration is chosen as the research object.Aiming at the shortcomings of the three spatial configurations,the balanced inflation volume of the front and rear suspension,the equivalent damping hole area of the suspension cavity 1 and 2,the short pipe length,the long pipe length and the pipe diameter are selected.Based on the joint simulation of Isight and Matlab/Simulink,the ride sensitivity analysis is carried out to determine the influence of these parameters on the two kinds of ride comfort of random pavement and pulse pavement.In order to significantly improve the optimization efficiency,Isight was used to establish a second-order response surface model for the comfort index.The accuracy of the second-order response surface model was illustrated by the fitting index R2.Considering the fact that vehicles will encounter both random road and pulse road during driving,the design variables,constraints and multi-objective functions of the multi-objective optimization design mathematical model for ride comfort are established,the constraint conditions of suspension dynamic deflection and relative dynamic load of wheels and the method of multi-objective function sequencing are proposed.On the basis of Isight and Matlab/Simlink joint simulation,the multi-objective optimization method AMGA was applied to optimize the smoothness of B-class road at60km/h and pulsed road at 20km/h,and the speed characteristics before and after the B-classroad and pulsed road were compared.The results show that the vehicle ride comfort can be improved by reasonable multi-objective optimization design.The above research shows that the integrated interconnected hydro-pneumatic suspension combination configuration analysis is helpful to determine the reasonable configuration;The plane configuration of the interconnected integrated hydro-pneumatic suspension can restrain the pitching angle and the dynamic deflection of the suspension,but it will lead to the deterioration of the acceleration of the pitching angle.The first and third space configurations of the integrated interconnected hydro-pneumatic suspension vehicle have certain anti-pitch and roll effects.It will improve the vertical acceleration and dynamic deflection of the suspension,and also worsen the acceleration of the pitching angle;Aiming at the problem of ride comfort,through the multi-objective optimization of ride comfort of integrated interconnected hydro-pneumatic suspension vehicles,the third spatial configuration of integrated interconnected hydro-pneumatic suspension vehicles can be improved in terms of ride comfort,so as to provide some theoretical and method reference for the research of integrated interconnected hydro-pneumatic suspension and its vehicles. |
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