This paper presents a fault detection and isolation scheme for multirate systems with a fast input sampling rate and slower output sampling rates. We design a separate observer for each set of simultaneous measurements with the observer operating at their sampling rate. We use an unknown input observer design to allow state estimation in the presence of disturbances and modelling errors. The ob...

Unknown input observers (UIOs) are observers that have stable error dynamics that are independent of unknown inputs. This paper studies such observers for nonlinear systems, and shows that the error dynamics for a nonlinear UIO has the same structure as the error dynamics of a nonlinear observer without unknown inputs. This result is first used to provide synthesis inequalities for UIOs for a c...

The estimation of road excitation profile is important for evaluation of vehicle stability and vehicle suspension performance for autonomous vehicle control systems. In this work, the nonlinear dynamics of the active automotive system that is excited by the unknown road excitation profile are considered for modeling. To address the issue of estimation of road profile, we develop an adaptive sup...

In this paper, a nonlinear motorcycle model is considered in order to estimate both the lean and steering dynamics. The model is transformed into a Takagi-Sugeno (T-S) form using the well-known sector nonlinearity approach. The first contribution of this work is the exactness of the obtained T-S model compared to the considered nonlinear model, where the weighting functions of the T-S model dep...

In this paper we investigate the observer design for Single-Input Single-Output (SISO) systems with unknown input. We find that the design conditions proposed by several authors in the past lead to unity relative degree of the plant and zeros of the plant in the open left half of the complex plane, for SISO systems. In other words an observer for a SISO plant with unknown input can be designed ...