Design of disturbance observers based on their implementability in industrial control systems

Abstract

The main objective in this thesis is to bring disturbance observers closer to control engineering practice, focusing in their applications in fault detection and disturbance rejection or fault tolerant control. Inspired by the reasons of PID popularity, we develop disturbance observers based in transfer function models found in preset tools from industrial control systems, such as DCS and PLC. We base the design in their implementability. For that, we use structures with only a few tuning parameters, whose effect on the system behaviour is intuitive. We develop tuning rules for the direct translation of the control or estimation requirements into the tuning parameter values. The design of the proposed algorithms is based on the trade-off between performance indices related with the engineering requirements. The proposed techniques and methods have been tested for several applications like a two-tank system, a wastewater treatment plant and distillation column from a chemical plant.