Controle preditivo em rede aplicado a um trocador de calor casco-tubos.

Abstract

The use of shared communication networks in control systems brings a number of advantages over the operation of these systems. The main advantages are: increased flexibility,systemscalability,easeof installationand reduced thenumberofcables. As disadvantages we can mention the insertion of delays, communication latency, packet loss and information security . Regarding to classical control systems, the disadvantages presented has serious implications on the functioning of these systems, so that instability conditions can be achieved if such impacts are not mitigated. This work presents the activities related to modeling, simulation and networked control of a heat exchanger shell-and-tubes using a strategy called Networked Predictive Control. In the modeling stage is obtained the dynamic equations of a heat exchanger shell-and-tubes, considering the out put temperature tubes and shell. The dynamic equations obtained are functions of several variables, including the logarithmic mean temperature difference. The model is linearized and therefore the state space representation of the process was obtained for later use in the model predictive controller. During the simulation fase, both models linear and nonlinear has been simulated and latter was connected to the predictive controller. By the architecture of Networked Predictive Control, was evaluated the impacts that communication delays existing in the meshes controller-actuator and sensor-controller, cause in a networked control system. From the simulator is possible to interconnect the controller and model plant, considering or not the existence of a delalys in shared networks. The results shows the change in the dynamics of the system when is considered delays inserted by the communication network.