Active Disturbance Rejection-Based High-Precision Temperature Control of a Semibatch Emulsion Polymerization Reactor

Abstract

A mathematical model can be used to mimic a real chemical, physical, or biological system. However, the process of idealizing the complicated real world into a relatively simple form requires making a set of assumptions and ignoring model variation, parameter changes, external disturbances, and noise. Therefore, no model can completely represent a real situation or process. On the other hand, if model uncertainties, parameter changes, and external disturbances are treated collectively as a “total disturbance” that is then estimated and canceled, extensive knowledge of the controlled object will no longer be required. In other words, good control performance is able to be achieved without a precise mathematical model. With this as the aim, active disturbance rejection control (ADRC), a modelfree control, presented in this paper is used to estimate and actively reject the inherent dynamic and external disturbances. In particular, it is shown in this paper that ADRC works well in the face of a nonlinear, time-varying process such as the Chylla–Haase semibatch polymerization reactor. This is because the problem of precise temperature regulation in the polymerization process can be reformulated as the problem of total disturbance rejection. The numerical results show the stability and robustness of the proposed method and better overall performance.