Performance Analysis of a 4-DOF Integrated Seat, Cabin and Wheel Suspension System

Contemporary research studies has treated wheel suspensions, truck cabin suspensions and seat suspension systems as separate entities whereas they are related. The dynamics of the individual systems and driver biomechanics contributes to the overall system dynamics. In this study, a combined seat, cabin and wheel suspension quarter vehicle of the 10 wheeled truck was modelled and simulated for response to deterministic and random road disturbance inputs (modelled based on ISO road class C and F for vehicle speeds of 45 km/h and 27 km/h respectively). Root-Mean-Squared (RMS) acceleration value of 1.071 m/s 2 was attained for the driver seat with the deterministic road disturbance input, while 1.172 m/s 2 and 8.661 m/s 2 were attained for the random road disturbance input at the two specified speeds respectively. The frequency domain analysis reveal that the seat mass acceleration response was amplified in the frequency band of 0.154 Hz and 8.69 Hz having a peak gain of 46.8 dB at 1.4 Hz. The frequency response also shows an amplification of vibration in the band of 0.155 Hz and 15.5 Hz attaining a maximum gain of 43.7 dB at 1.4 Hz for cabin and 0.158 Hz and 385 Hz attaining a maximum of 49 dB at 1.46 Hz for chassis. The system is stable and largely presented suspension travel values less than 11 cm but the vertical vibration values exceeded the ISO stipulated limits. Keywords: Suspension System, Whole-Body Vibration (WBV), Bode Plot, Time Domain Analysis