Distributed flow sensing for closed-loop speed control of a flexible fish robot.
Flexibility plays an important role in fish behavior by enabling high maneuverability for predator avoidance and swimming in turbulent flow. This paper presents a novel flexible fish robot equipped with distributed pressure sensors for flow sensing. The body of the robot is molded from soft, hyperelastic material, which provides flexibility. Its Joukowski-foil shape is conducive to modeling the fluid analytically. A quasi-steady potential-flow model is adopted for real-time flow estimation, whereas a discrete-time vortex-shedding flow model is used for higher-fidelity simulation. The dynamics for the flexible fish robot yield a reduced model for one-dimensional swimming. A recursive Bayesian filter assimilates pressure measurements to estimate flow speed, angle of attack, and foil camber. The closed-loop speed-control strategy combines an inverse-mapping feedforward controller based on an average model derived for periodic actuation of angle-of-attack and a proportional-integral feedback controller utilizing the estimated flow information. Simulation and experimental results are presented to show the effectiveness of the estimation and control strategy. The paper provides a systematic approach to distributed flow sensing for closed-loop speed control of a flexible fish robot by regulating the flapping amplitude.
Department of Aerospace Engineering and Institute for Systems Research, University of Maryland, College Park, MD 20742, USA.
Feitian
F
Zhang
Francis D
FD
Lagor
Derrick
D
Yeo
Patrick
P
Washington
Derek A
DA
Paley
D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D032701:Biomimetics / Q000295:instrumentation*; D017076:Computer-Aided Design; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D025461:Feedback, Physiological / Q000502:physiology; D005399:Fishes / Q000502:physiology*; D012212:Rheology / Q000295:instrumentation*; D012371:Robotics / Q000295:instrumentation* / Q000379:methods; D013550:Swimming / Q000502:physiology*; D014159:Transducers