In this work the problem of designing a reduced-order observer to infer the concentration in a catalytic reactor with temperature measurements and a simplified model is addressed. The process motion has a poor observability property, meaning that a carefully tuned high-order EKF technique is required to design an observer. Here, a constructive low-high gain estimation scheme is considered to ac...

In this paper, we focuses on the observer design problem for nonlinear neutral systems. The problem addressed that of designing a full-order observer that guarantees the asymptotically stable of the error dynamic system. The sufficient stability conditions are derived via Lyapunov–Krasovskii functionals (LKF). When these conditions, which are given in terms of linear matrix inequalities (LMIs),...

In this paper a design of an observer for Lipschitz nonlinear systems in the presence of time-varying delay in outputs measurements is proposed. The structure of the proposed observer is based on the presence of a proportional integral term which permits the compensation of delay in the measurements outputs. The observer gain is a function of the maximum bound of the delay, the parameters of th...

In this paper, we propose a new time-domain design of an Unknown Input functional Observer (UIFO) for delayed singular systems with known and unknown inputs. The order of this observer is equal to the dimension of the vector to be estimated. Constant and variable delays act on the known input vectors and a variable state delay is also taken into account. The proposed approach is based on the un...

We introduce a method of observer design for systems described by a linear part with a nonlinear perturbation, where the perturbation is parameterized by a vector of unknown, constant parameters. The design is modular, and consists of a modified high-gain observer that estimates the states of the system together with the full perturbation, and a parameter estimator. The parameter estimator is c...

This paper focuses on observer based fault reconstruction for a class of nonlinear uncertain systems with Lipschitz nonlinearities. An adaptive-gain Super-Twisting (STW) observer is developed for observing the system states, where the adaptive law compensates the uncertainty in parameters. The inherent equivalent output error injection feature of STW algorithm is then used to reconstruct the fa...

Disturbance observer based robot control algorithms provide good control performance while giving a straightforward method of gain selection. Unfortunately, the stability of these algorithms has not been shown rigorously for nonlinear systems such as robots. This paper demonstrates that a disturbance observer based algorithm can be made equivalent to the well-known passivity-based approaches of...

Based on a reduced-order, dynamic nonlinear wind turbine model in TakagiSugeno (TS) model structure, a TS state observer is designed as a disturbance observer to estimate the unknown effective wind speed. The TS observer model is an exact representation of the underlying nonlinear model, obtained by means of the sector-nonlinearity approach. The observer gain matrices are obtained by means of a...

This study proposes a solution to the speed control problem of servo machines in form multi-loop current sensorless with reduction system model dependence level and number feedback loops, which provides two contributions: first, model-independent observer estimates acceleration using only position measurement, thereby ensuring first-order estimation error dynamics; second, active damping stabil...