On tracking ability analysis of linear extended state observer for uncertain system

Shangyao Shi, Shiping Zhao, Jun Li

COMPUTER MODELLING & NEW TECHNOLOGIES 2014 18(2) 175-179

Department of Measurement and Control, Sichuan University, Chengdu 610041, P. R. China

It is known that the linear active disturbance rejection control (LADRC) is very an effective approach to control the uncertain systems. The linear extended state observer (LESO) is the major link of the LADRC, so this paper presents a modified LESO, which is used to track the state variables and estimate the unknown total disturbance. Furthermore, this paper redefines the “time-scaling” of the plant, which is a function with respect to the amplitude of the unknown total disturbance. It is first time to present the specified formula of the maximum sampling-period of LESO for some existing plants. On the anther hand, the tracking ability of the designed LESO is quantitatively described in this paper. The discussions and analysis, especially the quantitative formulas presented in this paper, will help the scholars and engineers to design the LESO in practice.