Vehicle Evaluation of the Performance of Magneto Rheological Dampers for Heavy Truck Suspensions

Abstract

This study is intended to complement many existing analytical studies in the area of semiactive suspensions by providing a field evaluation of semiactive magneto rheological (MR) primary suspensions for heavy trucks. A set of four controllable MR dampers are fabricated and used experimentally to test the effectiveness of a semiactive skyhook suspension on a heavy truck. In order to evaluate the performance of the semiactive suspensions, the performance of the truck equipped with the MR dampers is primarily compared with the performance of the truck equipped with the stock passive dampers. The performance of the semiactive system and the original passive system are compared for two different driving conditions. First, the truck is driven over a speed bump at approximately 8–11 kmh (5–7 mph) in order to establish a comparison between the performance of the MR and stock dampers to transient inputs at the wheels. Second, the truck is driven along a stretch of relatively straight and level highway at a constant speed of 100 kmh (62 mph) in order to compare the performance of the two types of dampers in steady state driving conditions. Acceleration data for both driving conditions are analyzed in both time and frequency domains. The data for the speed bumps indicate that the magneto rheological dampers used (with the skyhook control policy) in this study have a small effect on the vehicle body and wheel dynamics, as compared to the passive stock dampers. The highway driving data shows that magneto rheological dampers and the skyhook control policy are effective in reducing the root mean square (RMS) of the measured acceleration at most measurement points, as compared to the stock dampers.