2016 年 24 巻 1 号 p. 14-21
Parametric pendulum inherently exhibits a conversion from a vertical vibration into its rotational motion. The converting motion, which can directly drive a rotational generator, is associated with energy extraction from vibrations and movements of nature. The nonlinear characteristics of the parametric pendulum present various issues as well as the simple converting mechanism for the conversion of vibrational energy. This review article describes the dependences of the converting motion on the initial states and the excitation parameters and then the proposed methods to resolve the issues. In addition, we explore the application potentiality of the parametric pendulum for wave energy conversion.