Security Analysis of a Wireless Quadruple Tank Control System

Abstract: The main emphasis of this Master Thesis is the analysis of the effect of malicious deception attacks applied to a real process, in this case a scale model of a water distribution system made up of four interconnected water tanks and two pumps to control the water levels. The process model is derived, followed by the design and  est of three kinds of controllers: LQG, PI and PI robustified with the Glover-McFarlane method. Later, the performance of the closed loop system with these controllers is tested against a series of deception attacks, including the introduction of offset in the process inputs and in inputs and outputs at the same time, an output freezing, a replay of a series of output values and a zeroing output attack, using transmission zeros of the system and its properties. Some conclusions about the performance of Kalman filters, controls with integrators and the control robustification under attack have been achieved: there’s no remarkable difference of behaviour between the different controllers under attack, just little differences depending on the design with or without integrator; there’s neither difference of performance under attack in the case of PI and PI robustified control, and the residue of estimations with Kalman filters can be useful to detect any kind of attack.