Research Of Fuzzy Control And Simulation Of Semi-active Suspension

Suspension is a major component of modern automobile. It is the function of the road wheels on the role of the various forces are transmitted to the chassis(or load type body),to ensure that the vehicle under normal conditions. In addition, there is a good shock absorption and buffering capacity, to ease the impact of load, protecting body, passengers and cargo, restraining curb irregular vibration of the wheel. The vibration caused by outside interference is an important factor affecting the performance of vehicles. Vibration will affect the vehicle ride comfort and handling stability and fatigue life of the accessories, so effective vibration control of the car to improve overall performance as an urgent task with practical significance. To improve the performance suspension, active suspension and a semi-active suspension have been used.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 dissertation, nonlinear fuzzy method in allusion to semi-active suspension is investigated based on its characters to carry on research simulation.Compared with other conventional control algorithms, fuzzy control has advantages of being easy to build up model, high control precision and good nonlinear adaptability, etc, so it has been widely used in vehicle intelligent suspension systems. Vertical velocity and pitch angular velocity of sprung mass, and their change rate, were chosen as the inputs of fuzzy controllers, and the control of vehicle semi-active suspension was done with the use of double fuzzy controllers, which attained the comprehensive goal of vehicle vertical and pitching vibration. Meanwhile, a vehicle semi-active suspension model was chosen as the object for this simulation analysis. The results of simulation demonstrate that the fuzzy control mentioned above can not only improve the ride comfort, but also decrease the probability of suspension broke up.