A new observer for state and unknown inputs in linear time delay systems

This paper proposes a new state observer for linear systems with different time delays in the state and input. First, the system dynamics are rewritten as an augmented system with state vector including both the state vector of the system and the unknown inputs. Then, a reduced-order observer was designed to estimate both state and unknown inputs simultaneously. Conditions for stability of the reduced-order observer are translated into linear matrix inequalities (LMIs) which facilitates the design of the observer gains. Finally Simulation results demonstrate effectiveness of the proposed observer.

Keywords:

reduced-order , unknown input , time delay , Linear system , LMI