Control systems with internal models: A review

In the control system structural synthesis of there are three ways of internal model implementation: IMP (Internal Model Principle), IMC (Internal Model Control), and Tsypkin's IMPACT (Internal Model Principle and Control Together) structure. In the IMP, the model of external disturbance is included into the control structure in order to eliminate the influence of disturbance on controlled variable. In the IMC, the control structure comprises the plant model which enables the compensation of plant parameter changes. The IMPACT structure has been recently developed and it reveals advantages of the IMP and IMC control structures since it includes models of both the external disturbance and system plant and thus it attains the elimination of disturbance influence and a high system robustness with respect to changes of plant parameters. This paper gives the review of control structures with internal models, their features and capabilities of parameter design.