Control predictivo con modos deslizantes

Abstract

In the last 25 years, the strategies of advance control known as Variable Structure Control, in particular Sliding Mode Control (SMC), and Model Predictive Control (MPC) have experimented a great evolution. Their good characteristics of performance and the goal to overcome some of their particular disadvantages have motivated the execution of this thesis. On the basis of the theoretical fundamentals of SMC and MPC, some hybrid control laws are presented that use the First Order Plus Dead Time Model (FOPDTM) of a process to control. This model characterizes appropriately the majority of industrial processes and it is easy to be identified. Moreover, it is easy to program the developed control laws using Digital Control Systems and they can be applied to control processes that can be modelled as systems of non-minimum phase and as systems with high delays. Additionally several simple tuning rules have been developed, and they provide stable and smooth responses, even with a high level of structured and unstructured uncertainty in the model. The controllers have been designed from exact models and they have been tuned taking into account uncertainties. In several sections an analysis of stability and robustness have been carried out in order to complete the sections with the synthesis of the controllers. A chapter is dedicated to the simulation of the control laws applied to several systems. The results have been satisfactory as regards the step tracking and the rejection of disturbances in the outlet. They have been compared to GPC (C. Bordóns, 1994) and SMC (O. Camacho, 1996) and IM-SMC (O. Camacho et al, 2003), which are controllers obtained from the FOPDTM of the processes. Finally, the control laws have been programmed and applied to two non-linear real systems with uncertainties and disturbances. First, a heat exchanger in a circuit for recirculation of water, situated in a pilot plant at the "Departamento de Ingeniería de Sistemas y Automática" in the University of Seville (Spain); second, a field of distributed collectors of solar radiation, situated in the "Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas" in Tabernas (Almería, Spain).