A robust observer design is proposed for Takagi-Sugeno fuzzy neutral models with unknown inputs. The model consists of a mixed neutral and discrete delay, and the disturbances are imposed on both state and output signals. Delay-dependent sufficient conditions for the design of an unknown input T-S observer with time delays are given in terms of linear matrix inequalities. Some relaxations are i...

— 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...

An observer based scheme is proposed to detect sensor faults in wind turbines. In the example used for the proposed scheme the wind turbine drive train is considered. A model of the drive train is used to design the observer, and in this model the wind speed is an important input, however, if an unknown input observer the fault detection scheme can be non dependent on the actual wind speed. The...

The problem of constructing functional observers for linear systems with unknown inputs is considered. Necessary and sufficient conditions for the existence of a proper observer (without differentiations) are revisited. A simple and explicit form of a functional observer is presented. It is shown that when such observer is not proper, it is still possible to use the High-Order Sliding Mode diff...

This paper addresses parameter and state estimation problem in the presence of the perturbation of observer gain bounded input disturbances for the Lipschitz systems that are linear in unknown parameters and nonlinear in states. A new nonlinear adaptive resilient observer is designed, and its stability conditions based on Lyapunov technique are derived. The gain for this observer is derived sys...

In this paper, we propose an observer-based fuzzy adaptive control scheme for a class of multiple-input-multiple-output (MIMO) nonlinear non-affine systems with uncertainty and unknown state derivative. The proposed approach combines the recurrent-type fuzzy logic system (RFLS) and nonlinear observer to deal with the tracking control problem. It adopts the RFLS to approximate nonlinear unknown ...

A new quadratic digital tracker for efficient tracking control of an unknown sampled-data system with a direct transmission term from an input to output and subject to input constraints is proposed in this paper. First, the observer/Kalman filter identification (OKID) method is utilized to identify an appropriate (low-) order state-space innovation model with a feed-through term, equivalent to ...

This paper presents the design of a new reduced order observer to estimate the state for a class of linear time-invariant multivariable systems with unknown inputs. The proposed design approach is a combination of the approaches proposed by Hou & Muller [11] and Boubaker [4]; matrix decompositions, state transformations, and substitutions based on coordinates change are used. It will be shown t...

The unknown input estimation problem for linear dynamic systems exposed to the disturbances is studied in paper. A novel approach designing sliding mode observer suggested not satisfying matching, minimum phase, and detectability conditions. To apply this approach, reduced-order model of original system used. Such a allows reduce dimension observer, besides restrictions placed on are relaxed.