2 type controllers in which one is a model-based compensator (VSS controller to move a weight up and down along the pendulum member) and the other is a non-model-based compensator (a neural network controller to move another weight along the circumference) are adopted for the vibartion control of a pendulum system. It is found that the latter NN controller in the composite compensator system has more remarkable effect to suppress the vibration especially in lower amplitude region than the vibration control system including only the former compensator, and therefore that the composite control system shows a vibration suppressing effect over all vibration amplitude reglons. When the specific damping capacity (SDC) is used as a criterion for the vibration suppression effect, SDC=0.0884 in only the VSS control system, while SDC=0.0884 in the VSS system enhanced by the NN controller.