Long-distance sinusoidal actuation in self-propelling apparatus: a novel spiral spring-based crank rocker mechanism

Joshi, R and Arakeri, J (2024) Long-distance sinusoidal actuation in self-propelling apparatus: a novel spiral spring-based crank rocker mechanism. In: Sadhana - Academy Proceedings in Engineering Sciences, 49 (1).

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Abstract

Self-propelled oscillating foils provide an effective model system to explore the intricacies of oscillatory and undulatory bio-locomotion, particularly the coupled thrust and drag mechanism that enable self-propulsion. Here, we explain the design, construction, and working of an experimental apparatus that can achieve self-propulsion. Our apparatus utilizes a long, freely rotating arm pivoted on one end and houses the airfoil on the other. The novelty of the apparatus is a spiral-spring-based crank rocker mechanism employed to provide the necessary sinusoidal actuation to the airfoil. We discuss the kinematics of a four-bar crank-rocker mechanism and identify the conditions under which the rocker motion can be approximated as sinusoidal. We describe the mechanism's design and construction with these kinematic constraints, test it under various loading conditions, and observe that it can produce sinusoidal actuation up to 20°. As a characterization, we use the apparatus to record the self-propulsion speed in two airfoil models � rigid (NACA0015) and hybrid (NACA0015 with flexible flap). Our results demonstrate high repeatability and less than a 2 error in all cases. The apparatus can attain self-propelling speeds ranging from 1 cm/s to almost 45 cm/s. Additionally, we explore potential applications for the mechanism, such as in large robotic fishes. © 2023, Indian Academy of Sciences.

Item Type:	Journal Article
Publication:	Sadhana - Academy Proceedings in Engineering Sciences
Publisher:	Springer
Additional Information:	The copyright for this article belongs to Springer.
Keywords:	Kinematics, Crank-rocker mechanism; Design construction; Drag mechanisms; Experimental apparatus; Four bar; Modelling systems; Oscillating foils; Oscillatory locomotion; Self-propulsion; Spiral-spring based crank-rocke mechanism, Airfoils
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	29 Feb 2024 11:46
Last Modified:	29 Feb 2024 11:46
URI:	https://eprints.iisc.ac.in/id/eprint/83900

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