High gain observer for a class of nonlinear systems with coupled structure and sampled output measurements: application to a quadrotor

• Published in: International journal of systems science Vol. 50; no. 5; pp. 1089 - 1105
• Main Authors: Hernández-González, Omar, Guerrero-Sánchez, María-Eusebia, Farza, Mondher, Ménard, Tomas, M'Saad, Mohammed, Lozano, Rogelio
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis 04.04.2019; Taylor & Francis Ltd
• Subjects: Computer simulation; continuous-discrete time observer; High gain; high gain observer design; Non-uniformly observable nonlinear systems; Nonlinear systems; sampled output; Subsystems; unmanned aerial vehicle
• ISSN: 0020-7721; 1464-5319
• DOI: 10.1080/00207721.2019.1589596

This paper proposes a new high gain observer for a class of non-uniformly observable nonlinear systems with coupled structure driven by sampled outputs. The considered class of systems is particularly constituted by several subsystems where each subsystem is associated to a subset of the output variables. The observer design is carried out through two steps. First, a high-gain observer is proposed in the continuous-time output case under the assumption that an adequate persistent excitation condition is satisfied by each subsystem. Then, the proposed observer is redesigned to handle the case of sampled outputs leading thereby to a continuous-discrete time observer. The latter property is achieved thanks to the approach pursued along the convergence analysis. The effectiveness of the proposed observer is emphasised in a realistic simulation framework involving a mathematical model of a quadrotor which is diffeomorphic to the proposed class of considered systems.