Modeling And Test Of Lateral Interconnected Hydro-pneumatic ISD Suspension

Inerter is a new type of vibration isolation element with the characteristics of high frequency and low frequency resistance.Independent ‘Inerter-Spring-Damper'(ISD)suspension can isolate the transmission of low frequency vertical vibration from the road surface to the body,thereby improving the ride comfort of the vehicle.According to the comfort evaluation criteria,the human body is also sensitive to the roll vibration in the low frequency band.In order to make the ISD suspension suppress the roll vibration in the low frequency band and further improve the ride comfort of the vehicle,this paper proposes a lateral interconnected ISD suspension structure,which connects the left and right suspensions through the inerter and realizes the lateral connection of the suspension.In order to make the proposed lateral interconnected ISD suspension engineering,a lateral interconnected hydro-pneumatic ISD suspension is developed by using the method of fusion design.The structure of the suspension is simple,compact and easy to be deployed on real vehicles.Firstly,based on the new electro-mechanical similarity theory and the series resonance principle of LC(inductance-capacitance)circuit,a variety of lateral interconnected ISD suspension structures are proposed.The mechanical impedance method is used to analyze the transmission characteristics of each suspension structure,and combined with the hydro-pneumatic realization form of the lateral interconnected ISD suspension,an ISD suspension structure with good performance,simple structure and easy realization is finally selected.Secondly,the equivalent mathematical model of lateral interconnected ISD suspension is established based on MATLAB/Simulink,and the amplitude-frequency characteristics,impulse excitation response and random road excitation response of the two suspensions are simulated and analyzed by comparing the traditional passive suspension.In order to establish a more realistic lateral interconnected hydro-pneumatic ISD suspension model,a 15-degree-of-freedom model of the vehicle is built using AMESim,and on this basis,the key parameters of suspension are optimized by genetic algorithm.Taking the traditional hydro-pneumatic suspension as the comparison object,the random road excitation responses of the two suspensions are simulated and compared.The results show that the lateral interconnected hydro-pneumatic ISD suspension can effectively suppress the vertical and lateral vibration of the vehicle body and improve the ride comfort of the vehicle.Finally,a prototype of lateral interconnected hydro-pneumatic ISD suspension is designed and installed on the test frame.Taking the traditional hydro-pneumatic suspension as the comparative object,frequency offset test,hemi-body pulse test,torsion test,random input test and frequency response characteristic test are carried out respectively.The offset frequency test results show that the lateral interconnected hydro-pneumatic ISD suspension can reduce the natural frequency and low frequency resonance peak,and improve the low frequency vibration isolation performance;the hemi-body impulse excitation test,random excitation test and frequency response test results show that the lateral interconnected hydro-pneumatic ISD suspension can effectively suppress the vertical and roll vibration of the body,reduce the tire runout,so the ride comfort and tire grounding performance are improved;the torsion test of front suspension wheels and the torsion test of single diagonal wheels further show that the lateral interconnected hydro-pneumatic ISD suspension can significantly suppress the body roll vibration and improve vehicle ride comfort.