A fuzzy-energy regions based switching method has been studied to control Underactuated manipulators. The switching rule of this method was designed on sub-energy regions with several boundary curves represented by fuzzy reasoning. However, it was pointed out, through some simulations, that the number of switching times for partially stable controllers increased according to the initial conditions and design parameters. The present paper introduces a novel energy definition in the sense of monotonic decreasing and develops the corresponding switching rules with such energy, to reduce the number of switching times. The effectiveness of the proposed approach is verified through some simulations for a 2-link Underactuated manipulator.