Yang, Jun Chen, Wen-Hua Li, Shihua Non-linear disturbance observer-based robust control for systems with mismatched disturbances/uncertainties Robust control of non-linear systems with disturbances and uncertainties is addressed in this study using disturbance observer-based control (DOBC) technique. In this framework, the ‘disturbance’ is a generalised concept, which may include external disturbances, unmodelled dynamics and system parameter perturbations. The existing DOBC methods were only applicable for the case where disturbances and uncertainties satisfy so-called matching condition, that is, they enter the system in the same channel as the control inputs. By appropriately designing a disturbance compensation gain vector in the composite control law, a non-linear disturbance observer-based robust control method is proposed in this study to attenuate the mismatched disturbances and the influence of parameter variations from system output channels. The proposed method is applied to a missile system with non-linear dynamics in the presence of various uncertainties and external disturbances. Simulation shows that, compared with the widely used non-linear dynamic inversion control (NDIC) and NDIC plus integral action methods, the proposed method provides much better disturbance attenuation ability and stronger robustness against various parameter variations. Mismatched disturbances/uncertainties;Nonlinear disturbance observer;Disturbance compensation gain;Nonlinear missile;Mechanical Engineering;Engineering not elsewhere classified 2012-12-07
    https://repository.lboro.ac.uk/articles/journal_contribution/Non-linear_disturbance_observer-based_robust_control_for_systems_with_mismatched_disturbances_uncertainties/9227882