TY - JOUR
T1 - Unknown input observer design for linear time-invariant multivariable systems based on a new observer normal form
AU - Niederwieser, Helmut
AU - Tranninger, Markus
AU - Seeber, Richard
AU - Reichhartinger, Markus
PY - 2022
Y1 - 2022
N2 - In various applications in the field of control engineering, the estimation of the state variables of dynamic systems in the presence of unknown inputs plays an important role. Existing methods require the so-called observer matching condition to be satisfied, rely on the boundedness e variables or exhibit an increased observer order of at least twice the plant order. In this article, a novel observer normal form for strongly observable linear time-invariant multivariable systems is proposed. In contrast to classical normal forms, the proposed approach also takes the unknown inputs into account. The proposed observer normal form allows for the straightforward construction of a higher-order sliding mode observer, which ensures global convergence of the estimation error within finite time even in the presence of unknown bounded inputs. Its application is not restricted to systems which satisfy the aforementioned limitations of already existing unknown input observers. The proposed approach can be exploited for the reconstruction of unknown inputs with bounded derivative and robust state-feedback control, which is shown by means of a tutorial example. Numerical simulations confirm the effectiveness of the presented work.
AB - In various applications in the field of control engineering, the estimation of the state variables of dynamic systems in the presence of unknown inputs plays an important role. Existing methods require the so-called observer matching condition to be satisfied, rely on the boundedness e variables or exhibit an increased observer order of at least twice the plant order. In this article, a novel observer normal form for strongly observable linear time-invariant multivariable systems is proposed. In contrast to classical normal forms, the proposed approach also takes the unknown inputs into account. The proposed observer normal form allows for the straightforward construction of a higher-order sliding mode observer, which ensures global convergence of the estimation error within finite time even in the presence of unknown bounded inputs. Its application is not restricted to systems which satisfy the aforementioned limitations of already existing unknown input observers. The proposed approach can be exploited for the reconstruction of unknown inputs with bounded derivative and robust state-feedback control, which is shown by means of a tutorial example. Numerical simulations confirm the effectiveness of the presented work.
KW - multivariable systems
KW - normal forms
KW - robust state estimation
KW - sliding mode observation
KW - unknown input observer
KW - Multivariable systems
UR - http://www.scopus.com/inward/record.url?scp=85129181327&partnerID=8YFLogxK
U2 - 10.1080/00207721.2022.2046201
DO - 10.1080/00207721.2022.2046201
M3 - Article
SN - 0020-7721
VL - 53
SP - 2180
EP - 2206
JO - International Journal of Systems Science
JF - International Journal of Systems Science
IS - 10
ER -