Study On Nonstationary Ride Dynamics And Control Of Vehicle

Nonstationary ride dynamics of vehicle is an important aspect in the ride dynamics of vehicle, which mainly coves the vehicle nonstationary response, control and evaluation. With the increase in the numbers of vehicles, the density of traffic flow is also increased which results that vehicles move with non-uniform velocity on road such as accelerating and braking. The function of road roughness is regarded as a stationary random process in space domain, while road roughness is a non-stationary random process in time domain while a vehicle traveling at variable speed. Therefore the vibration caused by rough road surface should be also considered as a non-stationary random process. Therefore, the research on nonstationary ride dynamics of vehicle is practicable, which has a curtain significance and theoretical value in improving ride performance deducing structure noise, determining the dynamic random load and enhancing design quality of whole vehicle and components.Based on theory of stationary ride dynamics of vehicle about the vehicle dynamic model analysis methods, vibration control and so on, a detail analysis on vehicle nonstationary ride dynamics has been conducted using such theories as system dynamics, time-frequency analysis, correlation analysis, control theory as well as modern spectrum analysis. Especially, new methods in establishing nonstationary road surface models, analyzing the transient response spectrum and nonstationary control of suspension have been proposed. Chapter one introduces the research current state and development tendency, chapter two coves the modeling of vehicles suitable for the analysis and control including the nonlinear characteristics of components and mathematical model. Chapter three includes the approaches solving the nonstationary response such as double spectrums, evolutionary spectrum based on modal analysis. A new method called instantaneous spatial spectrum was put forward, and the equivalent covariance method has been developed. Chapters five includes the nonstationary random vibration test of a vehicle and the application of modern spectrum techniques maximum entropy spectrum to analysis of measured response. Chapter six coves the suspension control under the nonstationary random excitation based on the road surface model and gives the significant conclusions. Chapter seven involves the application of Wigner-Ville spectrum which gives the important characteristics of vehicle nonstationary...