Tracking a reference damping force in a magneto-rheological damper for automotive applications

Magneto-rheological dampers are gaining a lot of attention in the automotive industry and they show many advantages over their hydraulic counterpart. However, they are characterised by a highly nonlinear damping characteristics which may not be desired. In this paper, the authors present a control scheme which gives the possibility to track any reference damping force in a magneto-rheological damper. The main assumption of this research is the actual force exerted by the damper is not available for measurement, since such a sensor could not be installed onto a commercial vehicle. The control of this device is particularly challenging because of a singularity point in the origin which has significant repercussions on performance if not considered. The authors propose a novel closed-loop technique which is compared against an industrial solution based on an open-loop scheme, proving the former to be superior via a qualitative and quantitative analysis.