A new two degree-of-freedom event-based PI control strategy

In this paper, a complete event-based two-degree-of-freedom Proportional-Integral controller is presented. The architecture of the control system is based on two decoupled Proportional-Integral controllers, one for the set-point following and the other one for the load disturbance rejection task. The distinctive feature of the proposed approach is that, by assuming a first-order-plus-dead-time model of the process, the two controllers have the same parameters and the reference tracking performance is improved by suitably modifying the reference signal applied to the set-point following controller. Illustrative examples of the technique are given, including a comparison with an event-based one-degree-of-freedom ProportionalIntegral controller. © 2012 AACC American Automatic Control Council).