<p>Beam vibration control has gained immense attention from scholars in recent years, and the result has been plenty of studies in this regard. Since the materials of the beams under study have been predominantly metals or composite structures, this work uses a functionally graded material (FGM) beam for enhancing physical and thermal strength. This article presents active control of nonlinear vibrations in FGM beams with various limit constraints subjected to harmonic loading. Piezoelectric sheets are attached to the top and bottom surfaces of the FGM beam, serving as both actuators and sensors. The motion equations are discretized utilizing the Galerkin approach and resolved by numerical simulation. To minimize the vibration amplitude of the FGM beam, both feedback linearization control (FLC) and sliding mode control (SMC) techniques are employed. Five various limit constraints, i.e., clamped-clamped, clamped-free, clamped-simply supported, free-free, and simply supported-simply supported, are analyzed with displacement-time and voltage-time plots. The efficiency of the recommended control tactic is compared with and without uncertainties for all limit constraints.</p>