14BME0133 / RES001

nikhil.pandita2014@VIT.ac.in/

Optimum energy extraction from rotational motion in a parametrically excited pendulum. w/o Krishnan Nandakumar, Marian Wiercigroch, Anindya Chatterjee

Centre for Applied Dynamics Research, School of Engineering, University of Aberdeen, UK && Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India

Article info

Article history:
Received 14 May 2011
Received in revised form 12 March 2012
Available online 23 March 2012
Keywords:
Parametric pendulum
Energy extraction
Period-1 rotation
Damping

Abstract

A pendulum rotating under vertical base excitation is considered from the viewpoint of energy extrac- tion. Since the uncontrolled system can exhibit complex dynamics, we consider an added control torque and seek the optimal period-1 rotational motion for maximum energy extraction. We find, and con- firm through complementary methods, that the limiting optimal motion for harmonic base excitation is piecewise-constant: there are extended dwells at the top and bottom positions with rapid transitions in between. The limiting optimal solution gives about a quarter more energy extraction than uniform rotation, in the limit of no damping. Approximating motions with finite-speed transitions can be almost as good. Base excitations other than pure sinusoids are also considered and the corresponding optima determined.

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