Research On Damping Semi-active Control Of Quasi Zero Stiffness Automotive Suspension

With the rapid development of science and technology and the continuous improvement of people’s production and living standards,simple linear spring passive control systems cannot meet the vibration requirements of people in some application fields due to their poor low-frequency vibration isolation performance.A quasi zero stiffness system can greatly expand the isolation frequency band of the system,but it has a large amplitude at low frequencies.This article focuses on the study of quasi zero stiffness pneumatic spring automotive suspension systems with quadratic damping,and the main research content includes:(1)A quasi zero stiffness pneumatic spring automotive suspension system with quadratic damping was modeled and the mechanical properties of the spring and cylinder were analyzed.A mathematical model of a 1/4 vehicle single degree of freedom suspension system was established,and the forced vibration of the quasi zero stiffness automotive suspension system under the excitation of harmonic displacement under the spring was studied.The approximate analytical solution of the suspension system was calculated using the averaging method,and the stability criteria for the steady-state solution of the system were derived.The accuracy of the analytical solution was verified through numerical simulation.Compared to traditional pneumatic suspensions,quasi zero stiffness pneumatic suspensions broaden the effective vibration isolation frequency band of the system.Compared to traditional pneumatic suspensions,they have good vibration isolation effect at mid to high frequencies,but poor vibration isolation effect at low frequencies.The introduction of quadratic damping can reduce the amplitude near the resonance peak of a quasi zero stiffness system and reduce the initial isolation frequency of the system.The influence of quadratic damping on vibration control effectiveness was analyzed from the perspectives of weighted root mean square acceleration,transient displacement time history,and transient acceleration time history.(2)A mathematical model of a two degree of freedom system of a quasi zero stiffness pneumatic suspension with quadratic damping was constructed,and a dynamic analysis was conducted on the system model.The approximate analytical solution of the two degree of freedom system was calculated using the averaging method,and the stability criteria for the steady-state solution of the system were derived.The correctness of the approximate analytical solution was verified through numerical simulation.Analyzed the vibration control effects of a two degree of freedom quasi zero stiffness automotive suspension system compared to traditional pneumatic suspension systems in terms of amplitude and ride comfort.Discussed the influence of different parameters of quadratic damping and linear damping on the vibration control effect of the system.A study was conducted on the vibration isolation effect of a quasi zero stiffness pneumatic suspension system under different harmonic excitation displacement excitations.It was found that under larger displacement excitations,compared to a transmission pneumatic suspension,the quasi zero stiffness system has poor vibration isolation performance at low frequencies and may even exhibit amplitude jumps.In the case of small amplitudes,compared to traditional pneumatic suspensions,the system has very good vibration isolation control effect.(3)On the basis of the two degree of freedom system of the quasi zero stiffness pneumatic spring automotive suspension,semi-active control was introduced to study the vibration control effect of the semi active control under harmonic displacement excitation on the quasi zero stiffness system.The approximate analytical solution of the semi-active control system was calculated using the averaging method,and the stability criteria for the system were derived.The accuracy of the approximate analytical solution was verified through numerical solutions.Compared with passive control suspension,this semi-active control system has no significant change in amplitude at low frequencies with less damping,and has good vibration isolation effect at mid to high frequencies;In the case of high damping,the amplitude at low frequencies slightly increases,but there is better vibration control effect at mid to high frequencies.Overall,the semi-active control system can improve ride comfort while reducing system amplitude.