Study On Automobile Magnetorheological Suspension Vibration Control Algorithm And Road Test

With the rapid development of national economy, automobiles have become indispensable means of transportation. Ride comfort and road holding and handling stability are the important performance characteristics of the automobile. Accordingly, in order to improve ride comfort and handling stability, Magnetorheological (MR) semi-active suspension system has been studied, and has received broad attention in academe and automobile industrial circle. MR suspensions and corresponding technologies have been in research focus abroad a few years ago, and some achievements have been made. However, the domestic step has been left behind in the field. MR suspension control system consists of sensors, controller and actuators. Controller, which is a key component in MR suspension system, is significant for the vibration suppression effect. To develop MR suspension system independently, intelligent control algorithms investigation, vibration control software design and road test are of theoretical and practical significance. Based on the analyses of MR damper work characteristics and a quarter car suspension dynamical model, a MR suspension vibration simulation system is set up. The proposed sky-hook control algorithm, ground-hook control algorithm, hybird control algorithm, simple fuzzy control algorithm and adaptive fuzzy control algorithm are investigated. Corresponding controllers are designed for the controlling strategy. The MR suspension system with different control algorithms is implemented via SIMULINK Toolbox of MATLAB 6.1. The effectiveness of different control algorithms in various conditions are evaluated. To suppress whole automobile vibration, a hierarchical intelligent control strategy is discussed. The software design method of automobile MR suspensions vibration control is fulfilled. Based on DSP hardwares, in CCS software environment, different software modules are designed by C and assembly language, which include data sampling, coordination control, hybrid control, adaptive fuzzy control and result output, a whole automobile vibration hierarchical control software system is developed successfully. To validate the real results of hybrid and adaptive fuzzy control algorithm, a MR semi-active suspension control and test system is set up and is implemented on a mini bus, which is equipped with four MR controllable dampers. According to national experimental demands for the random input of automotive ride comfort, the hierarchical hybrid and adaptive fuzzy control software is used separately in the real control system when test bus is in various conditions, such as different road, vehicle velocity and load. The accelerations of driver's seat, body frame and across arms are sampled. The comparisons on the acceleration power spectrum and Root Mean Square (RMS) are carried out between the experimental results of the MR and the original suspensions. The analyses and evaluation based on the experimental results are carried out between the hybrid control algorithm and adaptive fuzzy control algorithm.The test results show that both control algorithms are effective to improve ride comfort and vehicle road holding stability respectively, the adaptive fuzzy control algorithm is more excellent on minimizing the effects of the quarter car model and test parameters changes, which are important factors to affect control system performance. And it is more suitable than hybrid one for whole MR suspension system vibration control. Road test resluts of the dynamical response characteristics of MR suspension system in frequency domain are consistent with those of the theoretical analyses and simulation investigations.