Application of a disturbance observer based controller to improve vehicle ride

Abstract

In this paper the application of a disturbance observer based control algorithm is proposed to improve the vehicle ride performance of a vehicle that has magnetorheological damper (MR Damper) suspension. The vehicle is modeled as a quarter car model by employing friction Lugre model of the MR damper. The proposed methodology is demonstrated on four different road profiles including step, ramp, bump, sine and rough roads as the disturbance. The controller performance of the proposed algorithm is benchmarked relative to the conventional PID controller on the basis of the rejection of the disturbance. The simulation results show that the DOB based controller outperforms the conventional PID when the control command signal is comparable to each other for all case studies. In addition, DOB can still reject the disturbance, while the conventional PID controller becomes unstable when the proportional gain is increased for better performance. The DOB controller performs quite well for the sine road profile with the excitation frequency close to the resonance frequency of the sprung mass as one of the most challenging case studies. The PID controller cannot suppress the road disturbance under such a condition.