Integrated Design And Analysis Of A Vibration Isolation System Of Cab Suspension For Heavy Commercial Vehicles

In recent years,with the development of vehicle technology,people's demand for ride comfort is getting higher and higher that the ride comfort has become an important indicator of heavy commercial vehicle design.It is difficult for the traditional“damper-spring"suspension to adapt to the complex road conditions,for its vibration isolation effect is poor.It is therefore of great significance to improve the suspension performance to achieve better ride comfort.The recent advent of inerter and "Inerter-damper-spring"(ISD)suspension has broken down the traditional suspension structure which was based on the classical theory of isolation,and provided a new platform for the development of suspension technology.To improve the suspension performance and take into account the layout space of the suspension,this paper is aimed to design and develop an ISD vibration isolation suspension system that can be used for commercial vehicle cabs by referring to the parameters of a heavy commercial vehicle.The ISD suspension system was integrated designed to optimize the internal structure of the air spring,damper and inerter.The main contents include:1.The ideal and reasonable layout of the three elements of the structure is based on a new mechanical and electrical analogy,mechanical impedance theory and mechanical network vibration isolation mechanism.The ISD suspension which will be developed as an ISD integration suspension system was integrated designed according to the internal structure and related parameters of three elements.2.The three degree-of-freedom 1/4 vehicle cab suspension system dynamics model was established firstly.The genetic algorithm to optimize the parameters of ISD integration suspension was proposed according to the multi-objective of the dynamic performance evaluation index of the ISD integration suspension and the multi-parameter of the characteristics of designing the ISD integration suspension,and the parameters of the three degree-of-freedom 1/4 vehicle cab ISD integration suspension was determined.The dynamic performance of the ISD integration cab suspension and a traditional cab suspension of prototype car were compared by the three degree-of-freedom 1/4 vehicle cab model simulation analysis.3.The dynamic model of the 1/4 vehicle cab suspension system enables analysis of vertical vibrations of the vehicle,which renders the modeling simple and convenient,but there are limitations in performance analysis.In addition to the analysis of the vertical vibration of the vehicle,the 1/2 cab model also takes account of the pitching vibration of the vehicle,and the suspension performance analysis is more comprehensive than the dynamic model of the 1/4 cab suspension system.Therefore,to describe the isolation performance of the ISD integration cab suspension more accurately,the six degree-of-freedom 1/2 vehicle cab suspension system dynamics model was established,and the genetic algorithm to optimize the parameters of ISD integration suspension was adopted according to the multi-objective of the dynamic performance evaluation index of the ISD integration suspension and the multi-parameter of the characteristics of designing the ISD integration suspension.The dynamic performance of the ISD integration cab suspension and a traditional cab suspension of prototype car were compared by the six degree-of-freedom 1/2 vehicle cab model simulation analysis.The results indicate that compared to the traditional cab suspension of prototype car,the cab acceleration,the cab pitch angular acceleration and the suspension dynamic stroke of the ISD integration cab suspension have improved significantly.Therefore,this study has demonstrated that the ISD integration cab suspension can improve the ride comfort and performance of vibration isolation stably.According to the optimized parameters,the part structure size of the front suspension device of the ISD integration cab suspension was designed,and the preliminary mechanical design of the device was completed.The design experience of designing suspension structure is accumulated through the research,which provides the theoretical foundation for designing and using the ISD suspension.