Disturbance attenuation and rejection for systems with unknown nonlinearity and missing measurements via DOBC approach

The problem of disturbance attenuation and rejection for discrete systems with unknown nonlinear and missing measurement is studied in this paper. Here, two types of disturbance are considered. One of them is matched unknown disturbance generated by an exogenous systems, the other belongs to norm-bounded disturbance. The matched unknown disturbance is estimated by disturbance observer (DOB). and it is compensated by the composited controller. The norm-bounded disturbance is attenuation under the condition of H-infinity constraint. The matched unknown disturbance and state are estimated separately based on missing measurement which is described by a binary switching sequence. The augmented systems, which consist of result closed-loop systems and error dynamic of disturbance are exponentially mean-square stable for zeros additional disturbance, and the systems also satisfy prescribed H-infinity performance requirement. A sufficient condition is derived to find DOB gain matrix, controller gain matrix in terms of Lyapunov approach. A numerical example is given to show the effectiveness of proposed method.