For non-affine nonlinear flight control systems, a non-affine nonlinear robust fault tolerance control method is proposed. Here, the fault tolerance control framework is used, and on this basis, observer-based auxiliary system is designed to implicit fault parameters and disturbances information. Then reconfigurable controller is designed using the dynamic of observer-based auxiliary system, wh...

Unknown input observer is one of the most important strategies for robust fault diagnosis of linear systems. Inspired by the unknown input Kalman filter, we extend it to nonlinear cases as the EKF does. Using this as a nonlinear observer, we prove its convergence under some mild conditions. As a result, a robust FDI strategy for nonlinear systems is obtained. Simulation studies on a three-tank ...

In this paper, we propose a polynomial fuzzy observer-controller for nonlinear systems where the design is achieved through the stability analysis of polynomial-fuzzymodel-based (PFMB) observer-control system. The polynomial fuzzy observer estimates the system states using estimated premise variables. The estimated states are then employed by the polynomial fuzzy controller for the feedback con...

In this paper, we establish the local separation principle for the class of nonlinear systems which is approximately error linearizable and locally asymptotically stabilizable. For this class of nonlinear systems, it is first shown that there exists a local nonlinear observer whose estimation error converges to zero exponentially. In order to achieve local output feedback stabilization, the pro...

A nonlinear observer for estimation of lateral and longitudinal velocity of automotive vehicles is proposed, based on acceleration and yaw rate measurements in addition to wheel speed and steering angle measurements. Stability of the observer is proved in the form of input-to-state stability of the observer error dynamics, under an assumption on the friction model. This assumption is treated wi...

Abstract—Necessary and sufficient conditions are presented under which a discrete-time autonomous system with outputs is locally diffeomorphic to an output-scaled linear observable system or an output-scaled nonlinear system in the observer form. As a consequence of such characterizations, the nonlinear observer design problem is studied by a time-scaling approach combined with the exact linear...

A state observer design procedure is proposed for nonlinear locally Lipschitz systems with high relative degree from the available for measurements output to the nonlinearity. The possible presence of disturbances is taken into account. The solution is based on logic-based control and the high order supertwisting observer. The approach is applicable to nonlinear systems with bounded solutions. ...

In this paper, by introducing the concept of command-to-state/output mapping, it is shown that the state of an uncertain nonlinear system can robustly be estimated if command-to-state mapping of the system and that of an uncertainty-free observer converge to each other. Then, a global Jacobian system is defined to capture this convergence property for the dynamics of estimation error, and a set...

A new fault detection method using neural-networks-augmented state observer for nonlinear systems is presented in this paper. The novelty of the approach is that instead of approximating the entire nonlinear system with neural network, we only approximate the unmodeled part that is left over after linearization, in which a radial basis function RBF neural network is adopted. Compared with conve...