Model-based observer and feedback control design for a rigid Joukowski foil in a K ármán vortex street

Obstacles and swimming fish in flow create a wake with an alternating left/right vortex pattern
known as a K ármán vortex street and reverse Kármán vortex street, respectively. An energy-efficient
fish behavior resembling slaloming through the vortex street is called K ármán gaiting. This paper
describes the use of a bioinspired array of pressure sensors on a Joukowski foil to estimate and
control flow-relative position in a K ármán vortex street using potential flow theory, recursive
Bayesian filtering, and trajectory-tracking feedback control. The Joukowski foil is fixed in
downstream position in a flowing water channel and free to move on air bearings in the cross-stream
direction by controlling its angle of attack to generate lift. Inspired by the lateral-line
neuromasts found in fish, the sensing and control scheme is validated using off-the-shelf pressure
sensors in an experimental testbed that includes a flapping device to create vortices. We derive a
potential flow model th...

Source: Bioinspiration and Biomimetics - March 14, 2018 Category: Science Authors: Brian A Free and Derek A Paley Source Type: research