Development of a semi-active suspension using a compact magnetorheological damper with negative-stiffness components

Semi-active suspension with traditional magnetorheological (MR) dampers can attenuate vehicle's vibration with less power consumption and high stability, nevertheless, it is not as effective as an active suspension. To further improve its vibration attenuation performance, this paper proposes a new MR damper with compact negative-stiffness components and analyses the effect of negative-stiffness characteristics on vibration attenuation performance. Its primary advantages include its high compactness which enables the suspension to be installed into the very limited space of real vehicles without any configuration change, and also its high effectiveness on reducing the vibrations as well as improving the vehicle stability. Upon the design of the new MR damper, a theoretical model and a mechanical model for the compact negative-stiffness component and the MR damper piston is established, respectively, to determine the suitable size of the negative-stiffness component and to optimize the parameters of the piston. Then the mechanical performance of the proposed new MRF damper is verified through an MTS machine. Finally, the new MR damper was mounted on a quarter-car system to evaluate its vibration attenuation performance under sky-hook algorithm by subjecting to different excitations. The experimental results demonstrated that the compact negative-stiffness MR damper has excellent vibration attenuation performance comparable to that of the active suspension.