Fuzzy Hybrid Control of Off-Road Vehicle Suspension Fitted With Magnetorheological Dampers

Abstract

The vibration caused by severe road excitation influences off-road vehicle suspension performance. The vibration control of the suspension system is a crucial factor for modern vehicles. Smart control devices (magnetorheological dampers) are proposed as a first step to handle a multiple suspension system of off-road vehicles. The magnetorheological (MR) dampers can be employed as smart dampers for vibration suppression of the suspension system; this is done by varying the produced damping force. In this paper an investigation is presented on the effectiveness of such smart dampers in attenuating the vibration of a multiple suspension system. This goal is accomplished by designing a new fuzzy hybrid controller and studying its effectiveness on the suspension performance. The multiple suspension system considered here comprises a chassis, five wheels and three MR dampers. The chassis is suspended over the five wheels through five compression springs. Three MR dampers are attached to the first, second and the fifth wheel. The stiffness of the wheels is represented by five compression springs. Only the bounce and the pitch of the chassis are considered. The assessment of the proposed model is carried out through a simulation scheme under bump and sinusoidal excitations in the time domain. The excitation of the five wheels is done independently. The simulation is accomplished using the MATLAB/SIMULINK software. The simulation results show the effectiveness and robustness of the new controller in conjunction with MR dampers in vibration suppression. Compared to the passive suspension, the body bounce, body displacement, angular acceleration and pitch angle can be well controlled NOMENCLATURE ‫ݖ‬ሷ ௪Wheel acceleration ‫ݖ‬ ሷ Body acceleration ‫ܩ‬ Groundhook gain ‫ܩ‬ ௦Skyhook gain ܸ ௫