Abstract

Sliding modes control (SMC) is a nonlinear control method with a systematic design procedure that allows to obtain a explicit solution for the control input. This method has some advantages, such as robustness against external disturbances and unpredictable parametric variations. On this work, two conventional SMC techniques, one using the error and other using the error integral, are designed and validated in a heat exchange system composed of a single pass circulation electric heater, whose control objective is to regulate the output temperature of the fluid, under the influence of external disturbances, such as variations in the flow and inflow temperature, manipulating the electric current passing through the heater resistance. The two SMC algorithms are analyzed using numerical simulations and their performance is compared through the integral absolute error and the integral absolute control input, selecting the best one to be tested experimentally. The experimental results indicate that the SMC is capable of fulfilling the control objective with satisfactory performance.  Keywords: Conventional sliding modes control; heat exchange system; nonlinear control.