| Suspension system is an important part of the whole vehicle,its performance is good or bad to a great extent affect the car ride comfort and handling stability,mainly composed of elastic elements,shock absorbers,guide components.Passive suspension in the form of elastic element is mainly for the steel plate spring,coil spring,torsion bar spring metal spring,spring stiffness and damping of this type cannot be changed,mainly designed for a particular condition,once the road conditions change,it will not be able to meet the requirements of new road conditions on the vehicle performance,as a result,there are some limitations on use.As a new type of suspension,hydro-pneumatic suspension is the elastic element for oil and gas spring,it,on the basis of traditional passive suspension is a combination of hydraulic drive technology and active control technology,can be changed according to real-time traffic to take the initiative to adjust the stiffness and damping of hydro-pneumatic spring,which can adapt to all kinds of road conditions,become the superior performance of active suspension.This paper takes the hydro-pneumatic suspension of a car as an example to analyze its performance and design the active control strategy and controller to effectively control the elastic force and damping force of the hydro-pneumatic suspension.The main contents are as follows:First,understand and master the research status of active control of oil and gas suspension in universities and enterprises,introduce the function and classification of suspension system and related knowledge,master the related control algorithm and master the principle of fuzzy control algorithm,and make full preparation for the following modeling analysis.This paper introduces several realizable working state of hydro-pneumatic suspension and the working principle of hydro-pneumatic spring,and establishes the physical model and nonlinear mathematical model of hydro-pneumatic spring.Determine the vehicle type and related simulation parameters,such as flow coefficient,hydraulic oil density,etc;Next,formulas of damping force,damping coefficient,elastic force stiffness coefficient were derived.The variable stiffness and nonlinear damping characteristics of hydro-pneumatic suspension were studied in depth.The influence of relevant parameters on suspension characteristics was analyzed in detail;Again,the controller is designed for the hydro-pneumatic suspension in this paper to control the damping force and elastic force of the hydro-pneumatic suspension,and three dynamic evaluation indexes of the suspension system are given;Finally,set up two degree of freedom model of passive suspension,the passive suspension system vibration differential equation is obtained,in the Matlab/Simulink simulation platform structures,the simulation model of passive suspension,the other wave signal and random signal incentives under suspension system simulation,simulation results and analysis of time domain and frequency domain,from body acceleration,suspension dynamic schedule,wheel dynamic load the three sides in the face of the vehicle ride comfort is analyzed,the results show that the controller designed in this paper are effective,to a certain extent,improve the ride comfort of vehicle. |
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