Robotic Fish Design and Control based on Biomechanics

Marine Technology Society Journal, 2014

Bioinspired robotic locomotion in the ocean environment can unveil critical issues on maneuverability, efficiency, and power consumption. This paper describes the modeling and closed-loop control of a bioinspired robotic fish. A body-caudal fin (BCF) carangiform swimming mode is presented. The propulsion scheme simulates the oscillatory motion of fish tail as thrust generator. The manufactured prototype is a 45-cm-long BCF mode four-joint, 6 degree of freedom modular robotic fish with a horizontal caudal fin (tail). The system uses DC servomotors as actuators and is controlled by microcontroller dsPIC33F. The mechanical CAD design in done in Solidworks and its 3D motion simulations in Matlab VRML, respectively. Lagrange-based dynamic modeling is done for the robotic fish. Based on the model, two nonlinear closed-loop control schemes, namely computed torque method and feed-forward control, both with dynamic PD compensation, are evaluated. This paper compares these model-based control...

IFAC Proceedings Volumes, 2008

The swimming backward for biomimetic carangiform robot fish is analyzed and implemented in this paper. The swimming law of the carangiform robot fish is modified according to the European Eel swimming mode based on the multiple-link structure to implement the backward motion. The motion mode difference between the eel and carangiform fish is discussed, and a qualitative kinematic analysis of the carangiform swimming in water is given to analyze the propulsion produced by the undulation of the multi-links tail. The experiments conducted demonstrate the good performance of the proposed method, and the results are given.

This paper is concerned with the design of a robotic fish and its motion control algorithms. A radio-controlled, four-link biomimetic robotic fish is developed using a flexible posterior body and an oscillating foil as a propeller. The swimming speed of the robotic fish is adjusted by modulating joint's oscillating frequency, and its orientation is tuned by different joint's deflections. Since the motion control of a robotic fish involves both hydrodynamics of the fluid environment and dynamics of the robot, it is very difficult to establish a precise mathematical model employing purely analytical methods. Therefore, the fish's motion control task is decomposed into two control systems. The online speed control implements a hybrid control strategy and a proportional-integral-derivative (PID) control algorithm. The orientation control system is based on a fuzzy logic controller. In our experiments, a point-to-point (PTP) control algorithm is implemented and an overhead vision system is adopted to provide real-time visual feedback. The experimental results confirm the effectiveness of the proposed algorithms.

2013

This paper presents simplified hydrodynamics model for a biomimetic robot fish based on quantitative morphological and kinematic parameters of crangiform fish. The motion of four Pangasius sanitwongsei with different length and swimming speed were recorded by the digital particle image velocimetry (DPIV) and image processing methods and optimal coefficients of the motion equations and appropriate location of joints are empirically derived. The swimming speed of fish can be adjusted by changing oscillating frequency, amplitude and the length of oscillatory part, respectively. Experimental results show that the oscillating amplitude increases dramatically from 1/3 of body and is very small near the head. So the second order function which describes wave amplitude of Pangasius sanitwongsei undulatory movement equation was found and the oscillatory motion of the biomimetic robot fish will be simulated according to this equation.

Springer Tracts in Mechanical Engineering, 2015

The study of fish locomotion provides a rich source of inspiration for the design of robotic devices. Fish exhibit an array of complex locomotor designs that involve both diversity of structures used to generate locomotor forces, and versatile behaviors to engage with the aquatic environment. The functional design of fish includes both a flexible body exhibiting undulatory motion as well as numerous control surfaces that enable fish to vector forces and execute rapid maneuvers in roll, pitch, and yaw directions. Patterns of body undulation have often been misunderstood, and fish with propulsive mechanics as diverse as tuna and eels can display similar patterns of body bending during swimming. Many of the often-cited classical locomotor categories are based on a misunderstanding of body and fin kinematics. Fish fins can exhibit remarkably complex conformational changes during propulsion, and do not function as flat plates but have individual mobile fin rays actuated by muscles at the fin base. Fin motion and surface bending in most fish is actively controlled. Even during steady horizontal locomotion, median fins such as the dorsal and anal fins function to balance torques and can contribute to thrust. Locomotion using body undulation is not achieved independently from fin motion, and the vast majority of fish locomotor patterns utilize both the body and fins. Robotic systems derived from fish templates can range from simple flexible plastic panels to more complex models of whole body and fin design. Experimental test platforms that represent individual fins or specific components of fish locomotor design allow for detailed testing of hydrodynamic and mechanical function. Actuating and controlling complex fish robotic systems involving both the body and multiple individual fins are a major challenge for the future.

Machines, 2022

Fishes have evolved different excellent swimming strategies. To study the influence of tail fin swing on the swimming performance of bionic robot fish, with one joint under the same tail swing frequency and amplitude, we designed a novel robot fish, driven by a double-cam mechanism. By designing the profile of the cam in the mechanism, the robot fish can achieve different undulatory motion trajectory of the caudal fin under the same tail swing frequency and amplitude. The mechanism simulated the undulatory motion of crucian carp. We studied the influence of undulatory motion on the swimming speed of robot fish, which was analyzed by dynamic analysis of the undulatory motion and experiments. According to the experimental results, we can find that the swimming speed of the robotic fish is different under various wave motions. When other conditions are the same, the speed that the robot fish can achieve by imitating the swing motion of the real fish is 1.5 times that of the robot fish ...

In this paper, types of fish swimming propulsion and the mechanics of fish locomotion are reviewed. Body and/or caudal fin (BCF) locomotion and median and/or paired fin (MPF) locomotion are two main categories of fish swimming propulsion. The swimming and characteristics of each propulsion mode are discussed for the development of fish robotics. Development of robotic fish propulsion involves several aspects such as shape of the robot, pattern of movement, hydro-dynamics, control system, location on the machine, mechanical properties and material properties. Various structures and materials used in existing fish robots and significance of selection are reviewed. Several actuators including conventional actuators have been considered. Ionic Polymer-Metal Composite (IPMC), piezoceramic materials, shape memory alloy (SMA) wires and pneumatic soft actuator have been recently attempted and their unique characteristics, advantages and limitations are discussed. Appropriate control system needs to be designed for proper propulsion of fish robots, hence various control system used in the past are presented. Finally, improvements and alternative technique for maneuvering the vessel are proposed.

2011

Biomimetic robots can potentially perform better than conventional robots in underwater vehicle designing. This paper describes the design of the propulsion system and depth control of a robotic fish. In this study, inspired by knife fish, we have designed and implemented an undulating fin to produce propulsive force. This undulating fin is a segmental anal fin that produces sinusoidal wave to propel the robot. The relationship between the individual fin segment and phase angles with the overall fin trajectory has also been discussed. This propulsive force can be adjusted and directed for fish robot manoeuvre by a mechanical system with two servomotors. These servomotors regulate the direction and depth of swimming. A wireless remote control system is designed to adjust the servomotors which enables us to control revolution, speed and phase differences of neighbor servomotors of fins. Finally, Field trials are conducted in an outdoor pool to demonstrate the relationship between robotic fish speed and fin parameters like phase difference, the number of phase and undulatory amplitude.

e-Journal of New World Sciences Academy, 2017

This study considers the dynamic model of one active joint robotic fish by using Lagrange method and simulation of the robotic fish model in MATLAB/SimMechanics environment. Compared results of these two different models are given in the study. The mathematical model of the system is derived from Lagrange energy equations of the robotic fish inspired from a real carangiform fish. The Computer Aided Design (CAD) model of the robotic fish is designed by using SolidWorks and it is transferred to the SimMechanics environment. The hydrodynamic effects, which are linear and nonlinear drag force, are also adapted and head motion, one active joint, and one passive joint angles found by using MATLAB Simulink environment. Obtained results for joint angles from both dynamic and SimMechanics models are compared and proved with animation video of the robotic fish.

In the last few years, there have been many new developments and significant accomplishments in the research of bionic robot fishes. However, in terms of swimming performance, existing bionic robot fishes lag far behind fish, prompting researchers to constantly develop innovative designs of various bionic robot fishes. In this paper, the latest designs of robot fishes are presented in detail, distinguished by the propulsion mode. New robot fishes mainly include soft robot fishes and rigid-soft coupled robot fishes. The latest progress in the study of the swimming mechanism is analyzed on the basis of summarizing the main swimming theories of fish. The current state-of-the-art research in the new field of motion coordination and communication of multiple robot fishes is summarized. The general research trend in robot fishes is to utilize more efficient and robust methods to best mimic real fish while exhibiting superior swimming performance. The current challenges and potential future research directions are discussed. Various methods are needed to narrow the gap in swimming performance between robot fishes and fish. This paper is a first step to bring together roboticists and marine biologists interested in learning state-of-the-art research on bionic robot fishes.

2014 IEEE International Conference on Robotics and Automation (ICRA), 2014

This paper presents a novel robotic fish, iSplash-I, with full-body coordination and high performance carangiform swimming motion. The proposed full-body length swimming motion coordinates anterior, mid-body and posterior displacements in an attempt to reduce the large kinematic errors in the existing free swimming robotic fish. It optimizes forces around the center of mass and initiates the starting moment of added mass upstream. A novel mechanical drive system was devised operating in the two swimming patterns. Experimental results show, that the proposed carangiform swimming motion approach has significantly outperformed the traditional posterior confined undulatory swimming pattern approach in terms of the speed measured in body lengths/ second, achieving a maximum velocity of 3.4BL/s and consistently generating a velocity of 2.8BL/s at 6.6Hz.

There have been increased interests in the research on mechanical and control system of underwater vehicles in the recent past. These ongoing research efforts are motivated by more pervasive applications of such vehicles including seabed oil and gas explorations, scientific deep ocean surveys, military purposes, ecological and waters environmental studies, and also for entertainments. However, the performance of underwater vehicles with screw type propellers is not prospective in terms of its efficiency and maneuverability. The main weaknesses of this kind of propellers are the production of vortices and sudden generation of thrust forces which make the control of the position and motion difficult. On the other hand, fishes and other aquatic animals are efficient swimmers, posses high maneuverability, are able to follow trajectories, can efficiently stabilize themselves in currents and surges, create less wakes than currently used underwater vehicle, and also have a noiseless propulsion. The fish’s locomotion mechanism is mainly controlled by its caudal fin and paired pectoral fins part. They are classified into BCF (Body and/or Caudal Fin) and MPF (Median and/or paired Pectoral Fins). The study of highly efficient swimming mechanisms of fish can inspire a better underwater vehicles thruster design and its mechanism. There have not been many studies on underwater vehicles or fish robots using paired pectoral fins as thruster. The work presented in this paper represents a contribution in this area covering study, design and implementation of locomotion mechanisms of paired pectoral fins in a fish robot. The performance and viability of the biomimetic method for underwater vehicles are highlighted through in-water experiment of a robotic fish.

Journal of Bionic Engineering, 2013

This paper presents the dynamic modeling of a flexible tail for a robotic fish. For this purpose firstly, the flexible tail was simplified as a slewing beam actuated by a driving moment. The governing equation of the flexible tail was derived by using the Euler-Bernoulli theory. In this equation, the resistive forces were estimated as a term analogous to viscous damping. Then, the modal analysis method was applied in order to derive an analytical solution of the governing equation, by which the relationship between the driving moment and the lateral movement of the flexible tail was described. Finally, simulations and experiments were carried out and the results were compared to verify the accuracy of the dynamic model. It was proved that the dynamic model of a fish robot with a flexible tail fin well explains the real behavior of robotic fish in underwater environment.

AI, Computer Science and Robotics Technology

Researchers have developed numerous artificial fish to mimic the swimming abilities of biological species and understand their biomechanical subaquatic skills. The motivation arises from the interest to gain deeper comprehension of the efficient nature of biological locomotion, which is the result of millions of years of evolution and adaptation. Fin-based biological species developed exceptional swimming abilities and notable performance in highly dynamic and complex subaquatic environments. Therefore, based on research by the scientific community, this mini-review concentrates on discussing the mechanical devices developed to implement the caudal propulsive segments of robotic fish. Caudal mechanisms are of considerable interest because they may be designed to control inertial and gravitational forces, as well as exerting great dynamic range in robotic fish. This manuscript provides a concise review focused on the engineering implementations of caudal mechanisms of anguilliform, s...

… and Computers in …, 2008

Abstract: - This paper is a review on design, fabrication and hydrodynamic analysis of a biomimetic robot fish that is made in Advanced Dynamic and Control System Laboratory, ADCSL, at University of Tehran. In order to build a fish-like swimming robot comprehensive hydrodynamic and ...