Abstract
Advances in image processing technology have made it possible to measure the surface shape of the road ahead while driving. We propose a new semi-active suspension control method that considers the forward road surface shape with MR damper. The MR damper uses MR fluid, which is a non-Newtonian fluid, is affected by Coulomb friction. In the simplified semi-active suspension model, the effect of the Coulomb friction is ignored. In this study, we design the semi-active control system considering the dynamics on the Coulomb friction of the MR damper. A vehicle model equipped with the MR damper can be expressed as an MLD (Mixed Logical Dynamical) model. When the shape of the road ahead can be measured accurately, it can be considered that the information on the future disturbances is available before the vehicle undergoes. In this paper, we formulate the finite time optimization problem of the MLD model in consideration of the future disturbances as a MIQP (Mixed Integer Quadratic Programming) problem in the same way as the conventional optimal control problem without future disturbance. The solution to the MIQP problem can be obtained by a commonly available solver software. The performance evaluation of the proposed method was carried out by a simulation. In the simulation study, the proposed method was able to achieve better ride quality, with an equivalent suspension stroke compared to the traditional MLD predictive control and the Skyhook approximation methods.
