Interval estimation for systems with time delays and algebraic constraints

International audienceThe problem of interval observer design is addressed for a class of descriptor linear systems with delays. Two sets of conditions are proposed. First, an interval observation for any input in the system is provided. Second, the control input is designed together with the observer gains in order to guarantee interval estimation and stabilization simultaneously. Efficiency of the proposed approach is illustrated by numerical experiment

On reduced-order interval observers for time-delay systems

International audienceThe estimation problem for uncertain time-delay systems is addressed. A design method of reduced-order interval observers is proposed. The observer estimates the set of admissi-ble values (the interval) for the state at each instant of time. The cases of known fixed delays and uncertain time-varying delays are analyzed. The proposed approach can be applied to linear delay systems and nonlinear time-delay systems in the output canonical form. The framework efficiency is demonstrated on examples of nonlinear systems

Finite-time estimation for linear time-delay systems via homogeneous method

International audienceThis paper presents a finite-time observer for linear time-delay systems with commensurate delay. Unlike the existing observers in the literature which converge asymptotically, the proposed observer provides a finite-time estimation. This is realized by using the well-known homogeneous technique, and the results are also extended to investigate the estimation problem for linear time-delay systems with unknown inputs. Simulation results are presented in order to illustrate the feasibility of the proposed method

Design summary of state-observers for linear positive time-delayed systems with disturbance

Design summary is invented and focuses on the steps in synthesizing positive state observers for linear positive time delayed systems with disturbance. If there is a delay in the information in the systems then this design provides an anticipation before it effects the real system

Automating Radiotherapy: Parameterizations of Sensor Time Delay Compensators and the Separation Principle

Motivated by recent research to automate radiotherapy, this thesis looks into feedback control problems where the feedback sensor imposes considerable time delay. The use of an asymptotic estimator is considered as a method to compensate for the time delay. Properties and parameterizations of asymptotic estimators are analyzed. It is shown that if such a delay compensation scheme is adopted, a separation principle holds, which allows for independent design of the feedback controller and the time delay compensator. The radiotherapy problem is used as a case study to show how asymptotic estimators may be designed, exploiting the separation principle. Lastly, the thesis considers multivariable versions of asymptotic estimators