Study On The Dynamics Characteristic And Active Control Of Airspring On Railway Vehicle

Raising the train riding speed is the target that has been pursue in the vehicle development always. Improving quality of vehicle in motion is more important with bigger velocity. The dynamics performance of bogie is the key to improve quality of vehicle in motion. The air spring has a low self-vibration frequency, an adjusted stiffness, a controlled damping, a good ability to reduce vibration and noise and a long service life. The air spring is the key component of the second suspension system widely on the rail bound vehicle. The semi-active control to air spring can improve quality of vehicle in motion for its controlled damping characteristic.In recent years, semi-active control is a new technology in the domain of rolling stock. The new method of enhancing dynamics performance of vehicle is put forward by semi-active control. The possibility of solving the increasingly outstanding antinomy of vehicle dynamics performance is provided by semi-active control. The reasonable Design of semi-active suspension system will not influence vehicle stability and ability of passing curve but improve the vehicle riding comfort to satisfy a request.In this thesis, basing on the finite element and the modern control theory, the vertical dynamic characteristic, the semi-active control controller design and suspension system simulation of the air spring suspension system studied. Some researches have been done as follows:(1) Thermodynamic characteristic, vertical stiffness characteristic and damping characteristics of the air spring were analyzed. Major effect factors of air spring mechanics characteristic and the relationship between the aperture and the damping of air spring damping hole were proposed.(2) Material non-linearity, geometry non-linearity, condition non-linearity and coupling between fluid and solid of air spring system were studied. Methods to solve these questions in mechanics characteristic analysis were proposed.(3) For example, SYS540 type air spring applied domestic abroad currently, Finite element model of the sir spring is made with ABAQUS, and then analyzed is vertical mechanics characteristic of the sir spring, which provide an availability reference for designing and making the air spring.(4) Basic principles of control strategy are studied, such as skyhook damper control, feedback control, optimal control, predictive control, decision control, adaptive control, H_∞control, fuzzy control, neural network control etc. And then making use of semi-active control technique analyze two the freedom degrees vehicle mode and six the freedom degrees vehicle mode of the air spring suspension system with optimal control strategy.(5) Dynamic mathematic models of the vertical suspension system were proposed, including the 6 degrees vertical model of the whole vehicle, the 2 degrees model of the 1/4 vehicle and the transmission function model.(6) A set of semi-active control project regulating the diameter of the air spring throttle orifice to adjust damping of the suspension system is put forward combining optimal control strategy. Semi-active control suspension system is simulated with software SIMULINK. The result indicated the designed controller could effectively reduce the vertical vibration of the vehicle, and improve the vehicle riding comfort.(7) By the analysis to the controller performance influence factors, the optimal control actual effect is decided by the selected weighting matrix in very great degree. All parameters and the working condition of the semi-active suspension system are completely same, but the result possibly can be completely different for selected weighting matrixes are different.