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Abstract

This document presents the design, implementation and comparison of algorithms to control the liquid level in a non-linear system of two coupled tanks. First, a Proportional-Integral (PI) controller was designed; then, a Model-based Predictive Controller (MPC) using the Non-linear Extended Prediction Self-Adaptive Control (NEPSAC) algorithm was designed. The performance of the controllers was evaluated in two scenarios: Setpoint Tracking and Disturbance Rejection. It is concluded that the NEPSAC algorithm presents better performance with respect to the PI, since the PI works correctly in regions very close to the setpoint while the NEPSAC, not requiring linearization of the system, has a performance that does not depend on the setpoint, presenting excellent characteristics at any reference point. To validate the results obtained, the Root Mean Square Error (RMSE) was used, which resulted in better values for the NEPSAC than for the PI.