Discrete-Time Active Disturbance Rejection Control: A Delta Operator Approach

The extended state observer (ESO) is a key component in any active disturbance rejection control (ADRC) scheme. Its discrete implementation is thus crucial in practical applications. In this paper, a discrete delta operator ESO is introduced and analyzed. As a starting point, a discrete shift operator ESO is used for transformation from continuous-time to delta operator discrete-time. A quantitative comparison between shift operator and delta operator ESOs (with different sampling time \(\varDelta \)[s]) is conducted here using a servomechanism system. The obtained numerical results show the proposed delta operator observer to work better than the shift operator observer in certain aspects.