Time-Delay Estimation Based Wireless-Networked Temperature Control System

Abstract

The temperature control is one of the prominently used control in many process industries. Moreover, localized control of this system might be a problem, specifically for high temperature situations. A communication network can be used that replaces the localized control by remote control. Thus, a temperature control system with a wireless network in the feedback loop is studied to investigate its various issues. The network is
introduced for sending temperature sensor signals to the controller. The advantages of using wireless network over erstwhile technologies are it eliminates the unnecessary wiring and hence simplifies the system. However, with these advantages, drawbacks like packet losses, time-delays, data packet disorder, etc. also follows which degrades the system performance. The major applications of this technology include industrial automation,
building automation, intelligent vehicles, remote surgery. This thesis focuses on development of both direct output feedback and observer based output feedback control algorithms for control of the above temperature control systems with network. A variable gain-type controller is used to improve performance of the
system in uncertain delay situation. In a variable gain controller, the gain varies in accordance with delay values at that particular sampling interval. To estimate these delay values, time-delay estimators based on error-comparison and gradient descent methods are designed. Using the knowledge of estimated delay values, the gain of the controller is chosen. Simulation studies were pursued using MATLAB to verify the efficacy of the
proposed controllers and estimators by considering appropriate model of the temperature control plant. The experimental studies using LabVIEW are also performed to validate the performance of the plant with the developed controllers and estimators.