Multisource disturbances rejection control for linear systems with unmeasured states under process and measurement disturbances

In this paper, a multisource disturbances attenuation and rejection control method is proposed for linear systems with unmeasured states under process and measurement disturbances. Since some internal states of control systems are hard to be measured via sensors in the realistic engineering process, a novel output feedback control scheme is proposed for designing the anti-disturbance controller by using measurement outputs, although these outputs mix with measurement disturbances. In addition, the dynamics of control system states also suffer from the influence of multiple process disturbances. To enhance the anti-disturbance ability of control systems, two kinds of disturbance observers are adopted to estimate process and measurement disturbances, respectively. And the anti-disturbance output feedback controller is constructed based on the process disturbance observer, state observer and H∞ control theory. In which the state observer is built via the measurement outputs and measurement disturbance observer. Then, the linear matrix inequality technology is used for analyzing the stability of closed-loop systems and decoupling the observers and the controller. Finally, the effectiveness of proposed control scheme is verified by using a numerical example.