A generalized active disturbance rejection control approach for linear systems

A generalized active disturbance rejection control (ADRC) approach is proposed for general linear systems. The method follows the idea of the conventional ADRC by using extended state observer (ESO) to estimate the generalized disturbance and using it in the feedback control to attenuate it quickly. It is observed that the idea is appropriate under a matching condition assumption. The generalized ADRC method makes it possible to incorporate any known information of the plant in the control instead of just using the order and the gain information, thus better performance can be achieved, especially for nonminimum-phase processes and unstable processes. Moreover, the generalized ADRC structure is transferred to the well-known two-degree-of-freedom internal-model-control (IMC) structure, thus the stability analysis and parameter tuning can be done in the IMC framework.