Hybrid Disturbance Observer-Based Anti-Disturbance Composite Control With Applications to Mars Landing Mission

In this paper, a hybrid anti-disturbance composite control scheme is presented to address the problem subject to systems remarkably affected by external disturbances and discrete dynamics of actuators. By explicitly considering the hybrid feature resulting from discrete actuation signals acted on a continuous system, the hybrid disturbance observer is designed to estimate the effect of external disturbance. Meanwhile, <inline-formula> <tex-math notation="LaTeX">${H_{\infty }}$ </tex-math></inline-formula> technique is used to mitigate the effect of continuous command executing error caused by discontinuous operation, which cannot be modeled <italic>in priori</italic>. Within the proposed composite control scheme, the combination of the disturbance estimation information and the <inline-formula> <tex-math notation="LaTeX">${H_{\infty }}$ </tex-math></inline-formula> technique enables the entire hybrid system precisely performing. The stability of the whole continuous–discrete control system is analyzed. Finally, based on the Mars lander dynamics, comparative simulation studies illustrate that the developed control scheme can preserve a satisfactory level of performance, even in the presence of external disturbances and actuator quantization errors.