Stability of sampled-data linear active disturbance rejection control: A classical control approach

Abstract

Stability of continuous-time and sampled-data LADRC is investigated with classical control approach. For the second-order uncertain LTI plant, the LADRC is described as an interconnection structure. Then sufficient conditions to guarantee continuous-time and sampled-data LADRC stabilizing the plant are proved respectively, while in proving the main theoretical tool is Nyquist diagram. With these results, a continuous-time controller designed with bandwidth tuning approach can be used as sampled-data controller after Euler approximation with a small sampling period.