Experimental Evaluation of Semiactive Magneto- Rheological Suspensions for Passenger Vehicles

Mechanical Engineering This study experimentally evaluates the dynamic response of a single vehicle suspension incorporating a magneto-rheological (MR) damper. A full-scale two-degree-of-freedom (2DOF) quarter-car test apparatus has been constructed at the Advanced Vehicle Dynamics Lab at Virginia Tech to evaluate the response of a vehicle suspension under the different control schemes of skyhook, groundhook, and hybrid semiactive control. The quarter-car apparatus was constructed using materials from 80/20 Incorporated and a hydraulic actuation system from MTS. A dSPACE AutoBox was used both for controlling the MR dampers and acquiring data. The first task was to understand the baseline dynamic response of the quarter-car system with only a passive damper. Next, the passive damper was replaced with a controllable MR damper. The control schemes of skyhook, groundhook, and hybrid semiactive control were applied to the MR damper. The physical response of the quarter-car with the different control schemes was then compared to the analytical prediction for the response, with favorable results. The response of the quarter-car with the semiactive damper was also compared to the response of the quarter-car with a passive damper, and the resulting limitations of passive damping are discussed. Finally, the practical implications of this study are shown in a discussion of the physical implementation of the MR dampers in the Virginia Tech FutureCar, a full-size Chevrolet Lumina. Although the actual skyhook, groundhook, and hybrid semiactive control schemes were not implemented on the vehicle, the results were promising and generated several recommendations for future research. iii Acknowledgments I would like to thank my advisor, Dr. Mehdi Ahmadian, for his help and encouragement throughout graduate studies in the Mechanical Engineering Department. I would also like to thank Drs. Douglas Nelson and William Saunders for serving on my graduate committee. I also would like to thank Lord Corporation and Koni Incorporated for donating the time and technical expertise to supply the Advanced Vehicle Dynamics Lab at Virginia Tech with the hardware used for this study. The generous donations by PCB Piezotronics Incorporated, Texas Instruments Incorporated, and the 80/20 Corporation, which made possible the many tests that were required for this study, are greatly appreciated. Finally I would like to thank my wife, Sarah, my mother and stepfather, Carol Paré and Robert Beaudette, my sister, Kim, and G for all their love and support during the time I have spent at Virginia Tech. Introduction The purpose of this chapter is to provide …