Kinematics study and implementation of a biomimetic robotic-fish underwater vehicle based on Lighthill slender body model

Abstract

Sir J. Lighthill mathematical slender body swimming model formulates the biological fish propulsion mechanism (undulation) in fluid environment. The present research has focused on the relevance of Lighthill (LH) based biomimetic robotic propulsion. The objective of this paper is to mimic the propulsion mechanism of the BCF mode carangiform swimming style to show the fish behavior navigating efficiently over large distances at impressive speeds and its exceptional characteristics. The robotic fish model (kinematics and dynamics) is integrated with the Lighthill (LH) mathematical model framework. Comparative studies are undertaken between a LH model based and a non-LH based model. A comprehensive propulsion mechanism study of the different parameters namely the tail-beat frequency (TBF), the propulsive wavelength, and the caudal amplitude are studied under this framework. Yaw angle study for the underwater robotic fish vehicle is also carried out as it describes the course of the robotic fish vehicle. Inverse kinematics based approach is incorporated for trajectory generation of the robotic fish vehicle motion. Analysis of these critical parameters affecting the kinematics study of the vehicle vis a vis the real fish kinematic study [8] is carried out for a given trajectory. TBF is found to be the effective controlling parameter for the forward speed of the vehicle over a wide operating conditions. Performances and comparative results of propulsive wavelength and amplitude variations are also shown and discussed.

Hydrodynamics study of a BCF mode bioinspired robotic-fish underwater vehicle using Lighthill’s slender body model

“…Therefore, the importance of relation between the geometry (morphological adaptation proposed by Lighthill) or degrees of freedom and their hydrodynamic effect on the body is investigated. This is undertaken by dividing the overall rigid body in to a multi-body modular system as proposed in the prototype design of the robotic fish underwater vehicle [19] in virtual animation toolbox in MATLAB as shown in its isometric view in Fig. 1a.…”

“…The NACA airfoil aerodynamic structure has been imparted to the design to boost the swimming efficiency by reducing the drag. The kinematics and dynamics studies [19] of the robotic fish prototype structure are undertaken in MATLAB/SIMULINK with variations in three parameters namely tail-beat frequency, amplitude span and propulsive wavelength. However, the tailbeat frequency and the amplitude span emerge as the dominant parameters in deciding the kinematic performance of the multi-body vehicle as will be highlighted later.…”

“…It attempts to understand the hydromechanics of the robotic fish vehicle under the Lighthill slender body model propulsion theory. The study would also be compared with the existing kinematic model parameters [19] effecting the locomotion. This paper also investigates the role of the morphological adaptations in fish (stated by Lighthill theory) in the undulatory wave generation and efficient biomechanical propulsion using computational fluid-structure interaction (FSI) techniques.…”

Kinematic study and implementation of a bio-inspired robotic fish underwater vehicle in a Lighthill mathematical framework

“…This mechanism uses a bioinspired algorithm under Lighthill cubic wave function as it is found to be the best result for trajectory generation. The simulation results [28,29] are useful during the closed-loop experimental verification [9] and operation of the robotic fish prototype as we know the variation of forward velocity with major kinematic parameters like tailbeat frequency (TBF), caudal amplitude (CA), propulsive wavelength (PW), and yaw angle. To enhance the system repeatability therefore reliability, each parameter is plotted for various wavelengths and operating tail-beat frequency values, resulting in the operating region.…”

“…Using the present dynamic model and derived steady kinematic simulation results [28,29], the closed-loop experiments [9] were done for different body motion configurations to emulate the undulation of the robotic fish in fluid environment shown in Figure 10.…”