Semi-active Control Of Air Suspension With Auxiliary Chamber

With the development of vehicle industry,in the process of design and production,in addition to meeting the most basic premises of safety and handling stability,there are increasingly stringent requirements for vehicle ride comfort and comfort in the industry.In the case that the traditional passive suspension is gradually difficult to fully meet the requirements,it is of practical value to design and control the new configuration of the suspension system.Therefore,this paper proposes a semi-active control scheme for air suspension with additional chamber to improve vehicle comfort.In order to achieve good results of semi-active control,in the design process of control strategy,besides considering the physical characteristics of air suspension itself,it is necessary to describe in detail the influence factors such as uncertainties of control system parameters,control delay,road preview information,and synergy among various control systems.Firstly,the concrete structure of air spring with additional chamber is introduced in detail,and the mathematical model is established.By comparing with traditional air spring,the advantages of air spring with additional chamber are highlighted,such as more ideal non-linear stiffness and air damp characteristics,and the effects of model parameters on spring characteristics are analyzed.Through sensitivity analysis and parameter optimization,the type size of air spring with additional chamber is determined,and the performance control method of air spring with additional chamber is put forward,which lays the foundation for semi-active control of air suspension afterwards.Then,the 1/4 vehicle dynamics model with additional chamber air suspension is established,and the semi-active suspension control system structure is constructed.Through detailed deduction and demonstration,a robust H∞ infinity control strategy is proposed.The uncertainties of suspension parameters and the influence of control delay factors are taken into account in the control strategy.The semi-active control of suspension is realized by means of the area of flow damper holes,and the inverse model of air spring for calculating the area of throttle damper holes is given.Then,a 1/2 vehicle dynamic model with additional chamber air suspension is established,and the influence of pavement preview information on semi-active control is analyzed as an object.The characteristics of the same front and rear wheels and pavement on the same side are taken as the basis of pavement preview,taking into account the uncertainty of parameters and the control delay.A suspension control augmentation system including road preview information is established.The control effect of semi-active preview control of air suspension is compared and analyzed through simulation test.Finally,the vehicle dynamic model with additional chamber air suspension is established,and the coordinated control of vertical,pitching and roll motion of the vehicle body is carried out.First,the sub-control laws of each control are designed separately,and then the weights of each control law are distributed according to the body state information to obtain the final coordinated control law.The control effect of semi-active cooperative control of air suspension is compared and analyzed by simulation test of vehicle under different working conditions.