An Analytical and Experimental Evaluation of Magneto Rheological Suspensions for Heavy Trucks

Abstract

SUMMARYThis study provides an analytical and experimental evaluation of the performance of magneto rheological (MR) primary suspensions for a heavy truck. The analytical aspect of the study includes the development of a roll-plane simulation model that is used for evaluating the effect of various control strategies for MR primary suspensions for improving both the ride comfort and roll stability of the vehicle. The simulation results are used in determining the most promising control approaches for a series of tests that are conducted on a heavy (class 8) truck. The tests include the use of four controllable MR dampers, which are installed on a Volvo VN series heavy truck. A real-time embedded controller is used to independently vary the damping force in each of the four dampers according to a skyhook control policy. The performance of the truck with the experimental dampers is compared with the truck with stock dampers for two distinct test conditions, a transient and a steady state driving condition. The results of a series of transient and steady state dynamic tests indicate that MR dampers with skyhook control policy can be more effective than passive stock dampers in lowering the RMS accelerations at most locations on the truck. This would lead to the conclusion that the use of MR dampers could increase operator comfort and reduce vehicle wear, over an extended period of time. The same data, however, shows an increase in the peak intensity of the measured acceleration in four frequency bands in the range of 1–19 Hz. Further study of the MR dampers, however, has shown that proper tuning of the semiactive controller on substantially reduce the acceleration peak intensity and the potential ride harshness.