In this paper a nonlinear state observer based on a distributed parameter model is proposed for a proton exchange membrane fuel cell (PEMFC). The estimation technique is implemented using a model-based nonlinear observer with a nonlinear disturbance observer in parallel. To implement the model, a nite element discretisation is performed to take advantage of the boundary conditions of the proble...

It is often difficult to measure all necessary parameters directly in the current stability control systems. This paper presents a nonlinear observer to estimate vehicle’s yaw rate, lateral acceleration, tire side slip angles and the road friction coefficient based on the measurement signals of the Electric Power Steering (EPS) system and the Anti-lock Braking System (ABS). The performances of ...

— Control of nonlinear systems with unknown disturbances is considered in this paper using disturbance observer based control (DOBC) approach. The disturbances concerned are supposed to be time-varying but with bounded variation. For a nonlinear system with well-defined relative degree from the disturbances to the output, a nonlinear disturbance observer is presented to estimate the unknown dis...

In this paper we present an observer for controlled nonlinear systems that are locally Lipschitz continuous in both the state and control variables. This observer is based on a recently introduced model of observer for autonomous Lypschitz continuous systems, and can be designed to realize an arbitrary, finite accuracy when both the state space and control variables evolve in bounded regions. K...

Extensions of sliding-mode adaptive observer are presented for state reconstruction of nonlinear systems with uncertainty having unknown bounds. The observer uses nonlinear gains that are smoothened versions of classical sliding-mode gains and they are continuously updated to guarantee a globally stable observation error. This observer is applied to Chua’s circuit in a chaotic synchronization s...

It is well known that the time-varying Kalman Filter (KF) is globally exponentially stable and optimal in the sense of minimum variance under some conditions. However, nonlinear approximations such as the extended KF linearizes the system about the estimated state trajectories, leading in general to loss of both global stability and optimality. Nonlinear observers tend to have strong, often glo...

A necessary and sufficient condition for the existence of a discrete-time nonlinear observer with linearizable error dynamics is provided. The result can be applied to any real analytic nonlinear system whose linear part is observable. The necessary and sufficient condition derived is associated with the solvability of a nonlinear functional equation. A corollary is Siegel’s theorem on the line...