“…Mechanical systems in general [Awrejcewicz, 2014;Slotine & Li, 1991] and the pendulum-like oscillators in particular [Capecchi, 1995;Alevras et al, 2015;Avanço et al, 2015;Leven et al, 1985], have been of interest in different studies in the field of nonlinear dynamic systems. In addition to its intrinsic interest, the pendulum is one of the most common models for many oscillators with many applications in engineering such as, marine structures, auto suspension systems, damping devices in civil engineering, etc.…”