Control And Simulation Research On Vehicle Macpherson Active Suspension Systerm

With the improvement of living income and the rapid development of the national economy and science technology, people have further views on car transport with the price, the appearance, fuel consumption feathers and more high requirements such as smoothness and riding comfort. Suspension is the main component of the vehicle, which plays a vital role in the smoothness and riding comfort of the vehicle. With the electronic technology and automatic control theory applied on active suspension developed, transverse and lateral motion is more accurate and effective, so that the vehicle has a good performance. Because MacPherson suspension has the advantages of small size, simple structure, less space occupation and advantage to the layout of the engine room, now a large part of the FF cars use of the MacPherson independent suspension, such as BMW’s M3, Porsche’s 911, Ford’s Focus and other car models, so the MacPherson active suspensions still have a great research value.Firstly, this paper established the random road input model and the traditional suspension model, then took the MacPherson suspension as the research object, established the MacPherson suspension model and the differential equations of motion. The following built the MacPherson suspension model, analyzed the response curve of the body acceleration and the control arm angular displacement with the input of random road spectrum and step function.Secondly, this paper took the MacPherson suspension with certain parameters as the research object and established the MacPherson active suspension with Fuzzy-PID controller. To solve the optimal parameters selection problem of fuzzy-PID controller of vehicle active suspension, genetic algorithm and its global optimization ability and parallel capacity are used to optimize the quantification factors and the correction coefficients of PID parameters.Finally, this paper introduce the influence of the uncertainty with sprung mass and the suspension damping coefficient on the amplitude frequency characteristic and the RMS of suspension performance index, then established the LPV model of the MacPherson suspension according to the uncertainty of the sprung mass. Through state feedback to the closed loop poles to a specific area and LMI technique, this paper designed a controller based on state feedback to reduce the amplitude of the body acceleration and the angular displacement of the control arm, and then took the random road as input and analyzed the response curve of the body acceleration and the angular displacement of the control arm and calculated the root mean square value, the following drew the power spectral density function curve and analyzed of the impact of the controller on vehicle ride comfort and suspension stability.