Observing systems with unmmeasurable inputs

Full-order observers for linear systems with unknown inputs

“…The problem of observing the state vector of a linear-time invariant multivariable system, subjected to unknown inputs, has received considerable attention in the last two decades [1]- [8]. One approach developed consists of modeling the unknown inputs by the response of a suitably chosen dynamical system [1].…”

“…One approach developed consists of modeling the unknown inputs by the response of a suitably chosen dynamical system [1]. This method, however, increases the dimension of the observer considerably.…”

On the Stock Estimation for a Harvested Fish Population

“…Several algorithms on the synthesis of "interval observer" has been proposed in the literature for continuous systems (Kurzhanski and Valyi 1997;Rapaport and Gouzé 2003) and for a discrete-time system (Jaulin et al 2001;Sheweppe 1968). Some algorithms have also been developed to solve the estimation problem for some classes of system with unknown inputs (Bhattacharyya 1978;Darouach et al 1994;Muller 1992, 1994;Hostetter and Meditch 1973;Jin et al 1997;Johnson 1975;Nikoukhah et al 1998;Sundaram and Hadjicostis 2007;Valcher 1999). Some of these observers carry out only the system state estimation, while other observers allow the estimation of the states as well as the unknown inputs of the system.…”

A subspace algorithm for simultaneous identification and input reconstruction

“…Approaches include full-order observers [6,4,7,16,19,25], reduced-order observers [1,5,12,13], geometric techniques [11], and trial-anderror methods [2]. A widely used approach is to model the unkno2n inputs as outputs of a known dynamic system and incorporate the input dynamics with the plant dynamics [10,27]. However, this approach increases the dimension of the observer and is limited to specific types of inputs.…”