this paper addresses the design of an observer-based fault diagnosis scheme, which is applied to some of the sensors and actuators of a wind turbine benchmark model. the methodology is based on a modified sliding mode observer (smo) that allows accurate reconstruction of multiple sensor or actuator faults occurring simultaneously. the faults are reconstructed using the equivalent output error i...

in this paper, a nonlinear model of the underactuated six degrees of freedom (6 dof) quadrotor helicopter was derived based on the newton-euler formalism. a new nonlinear robust control strategy was proposed to solve the stabilizing and path following problems in presence of external disturbances and parametric uncertainties. the proposed control structure consist of a sliding mode control base...

the problem of observer design for nonlinear systems has got great attention in the recent literature. the nonlinear observer has been a topic of interest in control theory. in this research, a modified robust sliding-mode observer (smo) is designed to accurately estimate the state variables of nonlinear systems in the presence of disturbances and model uncertainties. the observer has a simple ...

this paper presents a new control scheme for a class of nonlinear systems. in the proposed method, an adaptive neural network observer with rise feedback controller are applied to realize sensorless control scheme. this observer is tuned online and no exact information of nonlinear term of plant is required. so, this characteristic can compensate mismodeling phenomena. also, a new controller ca...

In this study, nonlinear second order systems with unmeasured system states and bounded external disturbances are considered. The observer gain of the sliding mode observer is adjusted by using a support vector machine based plant model. Computer simulations are presented to show the effect of the proposed adjustment mechanism on the performance of the output feedback sliding mode controller. I...

An improved sliding mode observer is presented to estimate the rotor position of the permanent magnet synchronous motors (PMSMs). In this observer, the discontinuous control is replaced by using the sigmoid function in order to reduce the chattering problem commonly found in the conventional sliding mode observer. When the chattering is reduced, the back emf can be obtained directly from the sw...

The conventional sliding mode controller needs the exact knowledge of system state measurements. In this study, nonlinear second order systems with unmeasured system states and bounded external disturbances are considered. The sliding mode observer based on nonlinear observation error dynamics is considered and the observer gain is adjusted by using a support vector machine based plant model. F...

The problem of designing sliding-mode observers for systems with unknown inputs is considered when the so-called observer matching condition is not satisfied. This condition severely restricts the applicability of sliding-mode observers. To circumvent the observer matching condition, thereby broadening the class of systems for which sliding-mode observers can be constructed, a possible method i...

In this paper, the performance of two adaptive observers applied to interconnected systems is studied. The nonlinearity of systems can be written in a fractional form. The first adaptive observer is an adaptive sliding mode observer for a Lipchitz nonlinear system and the second one is an adaptive sliding mode observer having a filtered error as a sliding surface. After comparing their performa...