On the Use of Rott’s Pendulum as an Energy Harvester for Rotating Systems

Rott’s pendulum is a two degrees of freedom system having two-to-one internal resonance. The objective of this work is to demonstrate that the Rott’s pendulum can be attached to a rotating system in order to transfer kinetic energy between the rotation applied to the pendulum and an electromagnetic generator linked to its main axis. In fact, the inertial and gravitational forces periodically applied to the Rott’s pendulum, can be used to generate large displacement responses that maximizes harvested energy through an electromagnetic generator. Two regimes were simulated: the constant rotation and the variable rotation speeds. For constant rotation speeds, three oscillation regimes can be distinguished: around the vertical axis, aperiodic and around the radial axis. Numerical results showed that the performance of the aperiodic regime is better in terms of output voltage and power. On the other hand, for variable speed conditions, we showed that the generated energy is very sensitive to initial conditions. In fact, the initial position of the Rott’s pendulum with respect to the direction of the gravity, highly affect its response. The results where confirmed by calculating the peak and RMS values of the harvested power.