Response characteristics of car seat suspension using intelligent control policies under small and large bump excitations

Abstract

Integration of semi-active devices in Automotive Seating System (ASS) with intelligent control policies help attenuation of the vibration transmitted to the occupant. The current work investigates the effectiveness of a semi-active magnetorheological (MR) damper with ASS for a quarter car model with the application of suitable control algorithms. The system controller calculates the desired damping force using proportional integral derivative (PID), skyhook on/off, PID tuned using genetic algorithm (GA), skyhook continuous and modified skyhook controllers. The signum function damper controller estimates the command voltage required for tracking the desired damping force. The displacement and acceleration of the passive seat system was compared with the semi-active seat suspension system in time and frequency domains. The results from the frequency domain shows that the lowest resonance peaks for the seat system can be achieved using the modified skyhook control policy. The effectiveness of the modified skyhook controller is evaluated in terms of peak to peak (PTP) acceleration, root mean square (RMS) acceleration, frequency weighted RMS acceleration, seat effective amplitude transmissibility (SEAT), vibration dose value (VDV) and crest factor (CF) for enhancing the ride quality. The modified skyhook controller can dissipate the energy better than the passive system. The modified skyhook controller increased the occupant ride quality of SEAT, VDV and CF by 30.41%, 52.84% and 11.62% on account of small bump excitation and 31.76%, 53.27% and 11.02% on account of large bump excitation compared with passive system. The modified skyhook control policy attenuates the vibration better than other control policies addressed in this paper.