Vehicle Roll Analysis And Control Of Semi-Active Suspension

With the rapid growth of highway mileage and the number of passenger vehicles, road safety accident showed a trend of rising. Vehicles with low roll stability are apt to roll in high speed cases, leading to physical threats and property loss. So roll stability attracts people’s interests. Therefore, people put forward higher requirements of vehicle ride performance and roll stability performance.According to real-time control of road conditions and vehicle status, active suspension can not only improve vehicle ride performance and ride comfort, but also strengthen the roll stability. However, considering about the complex structure and expensive cost of active suspension and the performance deficiencies of passive suspension, semi-active suspension based on parallel passive suspension magneto-rheological damper turns one of research direction. Combining road current input with good control method, the dissertation can give magneto-rheological damper a certain value of electric current to produce the desired damping force to achieve the optimal damping control and good vibration damping effect with a millisecond response. So magneto-rheological damper as the main structure form of the semi-active suspension shock absorber is one of the hot spot of current research.This paper selects the semi-active suspension with magneto-rheological damper as the research object, and establishes the Bouc-Wen model of magneto-rheological damping force, random road excitation model,1/2 passive and semi-active suspension model. This paper chose Fuzzy-PID control and optimal control algorithm. Based on half car body, Fuzzy-PID control selected body roll angle acceleration error and error change rate as the single output feedback variable. Combining Fuzzy control and PID control, this paper set up the composite controller, calculating controller parameter setting. In view of the semi-active suspension model, optimal control using body roll angle acceleration, the center of mass acceleration and other four output variables as control target, designed the optimal controller and calculated the gain matrices. In the Matlab/Simulink software, the paper not only set up semi-active suspension model and simulation model of the whole control system, but also carries on the simulation analysis under different vehicle velocity and road inputs. The simulation results show that with Fuzzy-PID control strategy or the optimal control strategy, semi-active suspension with magneto-rheological damper can reduce the vehicle direction vibration caused by vehicle velocity and road input and improve roll movement, reducing vehicle roll angle acceleration and increasing vehicle roll stability.