Whole Body Vibration Exposures: Comparison of a passive and active vibration cancelling semi-truck seat

Introduction:  Truck drivers have one of the highest injury rates in the US workforce with the largest proportion of those injuries occurring in the low-back. This group can operate their vehicles up to eleven hours a day and 60 hours per week. Exposure to Whole Body Vibration (WBV) is thought to be a significant contributing factor to pain and injuries in the low back.    

Methods:  This study compared differences in Whole Body Vibration (WBV) exposures between sixteen drivers who drove a semi-truck and trailer with a passive (air suspension) and an electromagnetically active suspension seat (EM-active). The EM-active seat was equipped with an accelerometer and onboard computer that monitored the vibrations transmitted to the seat column, and in real time, attempted to cancel out or reduce the vibrations using a linear electromagnetic force actuator.  A portable WBV data acquisition system collected time-weighted and raw WBV data per ISO 2631-1 and 2531-5 standards at 1,280Hz. Tri-axial measurements of average weighted vibration [A(8)], Vibration Dose Value [VDV(8)], and Static Compression Dose [Sed(8)] were compared between the two seats.      

Results:]  The results show that, when compared to the passive air suspension seat, the EM-active seat reduced A(8) and VDV(8) vibration exposures by half (p’s < 0.001) and impulsive exposures Sed(8) by approximately 20% (p =0.02).      

Discussion:  This study shows that the EM-active suspension seat has the potential to substantially reduce whole-body vibration exposures relative to the passive air suspension seats which are in the majority of semi-trucks today.