“…Mikhlin [18] and Feng et al [13] used the Padé and quasi-Padé approximation to construct these types of orbits. Other methods, such as the Homotopy perturbation [14], perturbation-incremental [6], hyperbolic perturbation [7,9], elliptic Lindstedt-Poincaré (LP) [3] and hyperbolic LP [8] methods and so on, have also been used to determine the homoclinic and heteroclinic solutions of both weakly and strongly nonlinear oscillators. Chen et al [9] used the hyperbolic perturbation method, involving a new time scale in the hyperbolic function, to derive the expressions of homoclinic orbits, where the systems were characterized by quadratic, cubic, quartic, and strong nonlinearity.…”