This paper presents a variable stiffness and variable damping (VSVD) electromagnetic damper for a quarter-car suspension system that aims to mitigate motion sickness and improve ride comfort. This novel device inspired by the force-current analogy consists of a direct current motor and an external circuit with an inductor and variable resistors. In this study, the Motion Sickness Dosing Value (MSDV) in vertical direction stated in ISO-2631 is used to evaluate the incidence of motion sickness, which is also used in this paper. The VSVD device was verified to have an excellent capability in controlling both damping and stiffness characteristics, which vary from 363.7 to 3573 Ns/m and 9.29 to 1694 N/m, respectively. A series of simulations was conducted under the frequency range of 0 – 1 Hz as the motion sickness is most likely occurred at a low frequency range; the sprung mass accelerations and MSDVs of different suspension systems from the simulation are evaluated, compared, and discussed in this paper. It was concluded that suspension with VSVD damper had significant improvement over the frequency range of 0.4 to 1 Hz in terms of vertical acceleration and MSDV.

University of Wollongong: Yulin Liao, Donghong Ning, Haiping Du, Weihua Li