Active disturbance rejection control based on internal model control for a class of processes with large time constant and time delay

Abstract Large time constant and time delay are common challenges in industrial processes, often leading to increased overshoot, prolonged settling times, larger steady‐state errors, and potential instability. This paper proposes a novel control strategy that combines linear active disturbance rejection control (LADRC) with internal model control (IMC) in a dual‐loop feedback structure (IMC‐ADRC) to address the challenges in systems with large time constants and time delay uncertainties. The inner loop, utilizing IMC, directly compensates for time delay, improving tracking performance. Meanwhile, the outer loop, using LADRC, estimates and suppresses both internal and external disturbances, reducing errors from disturbances and model uncertainties. Simulation results demonstrate that the integrated IMC‐ADRC approach significantly enhances system response accuracy, system response speed, and disturbance rejection compared to LADRC and IMC, as well as the delayed designed ADRC (DD‐ADRC) and Smith predictor‐based ADRC (SP‐ADRC). Notably, IMC‐ADRC retains these advantages even in systems with low model accuracy. This approach provides a robust and adaptable solution for systems with large time constants and time delays, thereby providing valuable perspectives for the field of industrial process control.