Influence Of Suspension On Comfort And Stability Of Special Rescue Vehicle

Compared with traditional rescue vehicles,special rescue vehicles have the advantages of good cross-country performance and strong functionality.Among them,the independent hydro-pneumatic suspension system is one of the key technologies that affect the ride comfort and driving stability of the whole special rescue vehicle.Based on the National Key R&D Program of China(No.2016YFC0802904),in order to improve the rescue efficiency of special rescue vehicles and the passage of special terrain,the stiffness and damping characteristics of suspension system are analyzed,and the dynamic characteristics of hydro-pneumatic suspension cylinder and the comfort and stability of special rescue vehicles are studied.The research contents include:(1)Mathematical models of hydro-pneumatic suspension systems with three different connection modes are established and their mechanical properties are analyzed.Taking the hydro-pneumatic suspension of high-speed heavy-duty special rescue vehicle as the object,the mathematical models of non-connected hydro-pneumatic suspension system,same bridge connected hydro-pneumatic suspension system and front and rear bridge X connected hydro-pneumatic suspension system are established respectively.Based on this,the stiffness characteristics and damping characteristics are analyzed through Matlab software.Through stiffness and damping characteristic curves and relevant formulas,the relevant parameters of the independent hydro-pneumatic suspension system of special rescue vehicles are matched.(2)The dynamic characteristics of hydro-pneumatic suspension are simulated and analyzed.AMEsim and Simulink software are used to carry out joint simulation.The working cylinder of independent hydro-pneumatic suspension system is taken as the research object.Through sinusoidal displacement excitation signals with different parameters and different types of displacement excitation signals,the corresponding working characteristic curves are obtained respectively.Finally,the change of excitation parameters and its influence on the working characteristics of independent hydro-pneumatic suspension working cylinder are summarized.(3)The road excitation model is established and the comfort of special rescue vehicles is analyzed.Among them,the excitation models of Class B and Class C pavements at different vehicle speeds are established.Through the virtual prototype of special rescue vehicles established in Trucksim,the characteristic curves of ride comfort of special rescue vehicles under different excitation models with the vertical acceleration of the driver's position as the characterization parameter are obtained respectively.(4)The pavement model of typical working conditions is established and the stability of special rescue vehicles is analyzed.Typical working conditions include: sine road driving condition,debris rescue condition,obstacle crossing condition and double moving line driving condition.Through the virtual prototype model established,the characteristic curves of stability under the respective working conditions are obtained by taking pitch angle,roll angle,yaw angle and vertical acceleration as characterization parameters.To sum up,the research content of this paper will help to improve the driving stability and riding comfort of special rescue vehicles,thus improving their competitiveness in the market.