The Research To Controlling Method Of Semi-active Suspension

Suspension is the important part of vehicle,it can improve stability and comfort of vehicle.The suspension system has three types:passive suspension,semi-active suspension and active suspension.Semi-active suspension,composed of controllable spring and damper,consumes little energy and is easy to design and manufacture. Not only can the semi-active suspension perform the function of active suspension system,but the requirements of the power is very few,so it has been a hot topic in the research field of vehicle.Automobile suspension is a complicated nonlinear system,and the traditional controlling methods take on certain limits,the fuzzy controller can be applied to complex nonlinear system.Compared with the traditional adaptive systems, the fuzzy controller not only meet the more stringent performance requirements, but it is also applicable to the wider systems of environment of uncertainty. In this dissertaion,nonlinear fuzzy method in allusion to semi-active suspension is investigated based on its characters to carry on research simulation.This research is based on vehicle semi-active suspension system,and set up a quarter vehicle of two DOF suspension mathematical model,half vehicle of four DOF model and half vehicle of five DOF model and road model,and derives the dynamic equation of suspension.In this dissertation, the fuzzy logic control system based on semi-active suspension is proposed to achieve the objective of adaptive damping control,with changing the adjustable dampers by controlling output signal dynamic. The models half vehicle of four DOF a quarter vehicle of two DOF use their own means of fuzzy control,and the model of five DOF uses the fuzzy controller of the model of four DOF after few parameters is modified. Finally, the software Matlab is used to simulate the semi-active suspension controlled by the above-mentioned fuzzy control method on B level typical road and Sine wave,and the results prove the semi-active suspension can obviously improve the comfort.The above researches have important reference value for the study of vehicle electronically controlled systems and semi-active suspensions, and also provide excellent basis for the actual applications to automobiles manufacture in China. Furthermore, the research project lays the theoretical foundation for further study on automobile dynamics and computer control.