Dynamics of a parametric N-pendulum with a view on energy harvesting from the motion of a reciprocating oil pumping unit?. XVIII International Symposium on Dynamic Problems of Mechanics (DINAME)

DOTTI, FRANCO E.; REGUERA, FLORENCIA; MACHADO, SEBASTIÁN P.; OSINAGA, SANTIAGO M.; VERA, CARLOS A.

Congreso; Proceedings of the XV International Symposium on Dynamic Problems of Mechanics; 2019

The nonlinear dynamics of a parametric pendulum system excited by the motion of a reciprocating oil pumping unit is explored. The final goal of this investigation is to recover energy from such machines by means of pendulum harvesters located on a walking beam. Being the parametric pendulum a potential well system, the study is concentrated in rotational responses which are the most energetic state. A pendulum with multiple concentric masses, i.e. a N-pendulum, is considered in the design. This provides versatility, since it allows the tuning of the natural frequency of the system. The nodding motion provided by the pumping unit is a planar motion, thus containing both vertical and horizontal components. Such feature has a strong influence in the dynamics of the system, as introduces an asymmetry in the governing equation. It is shown that, by virtue of this asymmetry, the pendulum system experiences a complex rotational behavior, very different to the widely studied classic parametric pendulum with a sinusoidal forcing.