Biomimetic Underwater Vehicle Research Articles

Analysis of Parameters of Traveling Wave Impact on the Speed of Biomimetic Underwater Vehicle

The paper is focused on presenting first steps in attempting to build model of the motion of the biomimetic underwater vehicle (BUV) based on experimental studies of traveling wave parameters on the robots speed. In the introduction the mechanical and electronic part of the fifth version of BUV called CyberFish is shortly presented as well as its enhanced motion principle based on traveling wave. The second paragraph covers experiment description and discusses its results.

Design and Kinetic Analysis of a Biomimetic Underwater Vehicle with Two Undulating Long-fins

A biomimetic underwater vehicle propelled by two undulating long-fins is introduced in this paper. The concerned vehicle is propelled by two symmetrical undulating long-fins installed on both sides. Ten servo motors are employed to drive the long-fins and cosine wave function is employed for motor control. A real-time control system is designed for controlling the long-fins by adjusting its oscillating frequency and oscillating amplitude. An inertial measurement unit is installed to collect the accelerations and angular velocity. To obtain the relationship between oscillating frequency/amplitude and swimming performance, kinematic analysis and hydromechanic analysis are given. By dividing the long-fin into many small elements and computing the hydrodynamic force acting on each element, the instantaneous thrust generated by the long-fin is obtained. Then the average thrust of the long-fin is obtained by summing up the forces acted on the elements in one undulating period. Then swimming experiments are carried out to validate the vehicle design and kinematic analysis and hydromechanic analysis. And two swimming motion modes including marching and rotating locomotion are chosen. Finally, discussions between the swimming performance and the oscillating parameters are given.

Surge performance of an underwater vehicle with a biomimetic tendon drive propulsion system

This article presents a study into the forward propulsion of a free swimming, custom-built biomimetic underwater vehicle called the RoboSalmon developed at the University of Glasgow, Scotland. As the name implies, the design of this vehicle is based on the dimensions of an Atlantic salmon. It realises fish-like propulsion through a tail assembly that utilises a tendon drive actuation system driven by a single servo motor. A brief overview of the experimental hardware is given followed by a discussion of the accompanying mathematical model of the vehicle. Experimental results are presented for straight swimming trials that show the surge velocity performance of the vehicle. In the context of forward swimming, the efficiency and power consumption of the vehicle are analysed, and the adverse effect of tail recoil is discussed.

Experimental and analytical study on factors influencing biomimetic undulating fin propulsion performance based on orthogonal experimental design

This paper presents an experimental study on the structural and motion parameters of a biomimetic mechanical fin, as actuators for biomimetic underwater vehicles, and their influences on its propulsion performance. Orthogonal experimental design method is employed to optimize the test scheme due to its capability of reducing experiment time and rapid determination of influencing factors. A L64 orthogonal array is adopted in our seven-factor mixed factorial experiment with three structure parameters and four motion parameters. The experimental results of range analysis and variance analysis are discussed. The statistic results show that the fin-ray configuration, sway frequency, wave number, and rigidity of membrane are the primary factors affecting the integrated propelling performance of the biomimetic mechanical fin. Optimizing these parameters needs to compromise the propelling speed, efficiency, and maximum output power of the actuator. The analytic results are also in agreement with theoretical analysis and simulation study on inclined angle of fish fin-ray. Consequently, proper modification of the inclined angle of the fin-ray might improve not only the propelling speed and acceleration but also the propelling efficiency.

Flow-relative control of an underwater robot

This paper describes flow-relative and flow-aided navigation of a biomimetic underwater vehicle using an artificial lateral line for flow sensing. Most of the aquatic animals have flow sensing organs, but there are no man-made analogues to those sensors currently in use on underwater vehicles. Here, we show that artificial lateral line sensing can be used for detecting hydrodynamic regimens and for controlling the robot’s motion with respect to the flow. We implement station holding of an underwater vehicle in a steady stream and in the wake of a bluff object. We show that lateral line sensing can provide a speed estimate of an underwater robot thus functioning as a short-term odometry for robot navigation. We also demonstrate navigation with respect to the flow in periodic turbulence and show that controlling the position of the robot in the reduced flow zone in the wake of an object reduces a vehicle’s energy consumption.

Sound Silencing Problem of Underwater Vehicles

This paper describes some common problems associated with negative influence of UUV self noise on detection aspect in water environment. Some tasks of military applications require silent behavior of UUVs: Intelligence, Surveillance, and Reconnaissance (ISR), Rapid Environmental Assessment (REA), Mine Countermeasure (MCM) etc. Moreover, this paper review methods of underwater sound measurement and on the end as a summary presents results of an experiment from the water tank trials where were investigated three UUVs: one ROV and two biomimetic autonomous underwater vehicle.

The Analysis of Possibility of Using Electromagnetic Drive for Autonomous Biomimetic Underwater Vehicle

Striving for a perfect imitation of fish motion is one of assumptions of building autonomous biomimetic underwater vehicle. Usage of typical servomechanisms gives good results, but it is important to eliminate their two main disadvantages: large power consumption and constant torque in whole range of motion. In the paper, an analysis of possibilities of using set consisting of a permanent magnet and an induction coil for electromagnetic drive of the vehicle was included. Values of driving torque and character of its change in comparison with muscle system of fish were estimated.

Aurelia aurita Inspired Artificial Mesoglea

In this preliminary study, we report the mechanical and dielectric properties of polyvinyl alcohol (PVA)-ferritin hydrogel. This material was found to exhibit close resemblance to Aurelia aurita (jellyfish) mesoglea in terms of stiffness modulus and water content. Systematic experiments were conducted on natural jellyfish to identify its compression modulus a function of deformation. In compressive testing Aurelia aurita mesoglea was found to exhibit nonlinear modulus in the range of −10 kPa to 70 kPa depending upon the compressive strain (0–50% strain). The negative stiffness is an artifact of tensile force experienced by the specimen at the beginning of the test due to surface tension. PVA hydrogels with 60% water to dimethyl sulfoxide (DMSO) ratio without ferritin particle (H60) and PVA hydrogels with 80% water to DMSO ratio with ferritin particle (F80) provided a good alternative to natural jellyfish mesoglea exhibiting shear modulus of 33.06 Pa and 39.99 Pa respectively as compared to 4.75 Pa for Aurelia aurita mesoglea. This is a significantly better match compared to the 1041.67 Pa shear modulus of Ecoflex, a soft polymer material commonly used in biomimetic robotics. A Mooney Rivlin model suggests that H60 and F80 compositions are about 6.9 times and 8.4 times stiffer than natural Aurelia aurtia mesoglea whereas Ecoflex is 219 times as stiff. Nanocomposite hydrogel consisting of PVA matrix and ferritin nanoparticles were found to exhibit higher durability over regular PVA hydrogels and had more consistent properties due to increased cross-linking at ferritin nanoparticle sites. The ferritin nanoparticles were found to act as springs, increasing the modulus by increasing the surface area of the cross-linked polymer chains and disrupting long linear chain patterns of the polymer. Natural Aurelia aurita was found to have water content of 96.3% with a standard deviation of 0.57% as compared to 85% water content of PVA-ferritin hydrogels. Use of this material in the design of biomimetic unmanned underwater vehicles is expected to reduce the power consumption, increase swimming efficiency, and better replicate the rowing kinematics of naturally occurring Aurelia aurita.

Three Dimensional Measurement of Shark Body Based on Monocular and Binocular Vision

To provide precise configuration reference for the engineering bionics, high accuracy detection in large field of view on the natural biological body is a prerequisite. Targeting the streamline body of carcharhinus brachyurous, 3D (three dimensional) measurement was carried out with monocular and binocular vision inspecting system based on sinusoidal structure light. By means of moving the vision sensor driven by a stepper motor, fringe patterns with variable fringe spacing were projected to every parts of the shark body, then the point clouds of different parts of the whole shark body were obtained. Using the quaternion method to joint the edges of these point clouds together, surface reconstruction was conducted. Finally the digital model of the low resistance body of shark was achieved. It would be useful reference for the configuration design of underwater vehicles, especially microminiature biomimetic underwater vehicles.

Biomimetic jellyfish-inspired underwater vehicle actuated by ionic polymer metal composite actuators

This paper presents the design, fabrication, and characterization of a biomimetic jellyfish robot that uses ionic polymer metal composites (IPMCs) as flexible actuators for propulsion. The shape and swimming style of this underwater vehicle are based on the Aequorea victoria jellyfish, which has an average swimming speed of 20 mm s−1 and which is known for its high swimming efficiency. The Aequorea victoria is chosen as a model system because both its bell morphology and kinematic properties match the mechanical properties of IPMC actuators. This medusa is characterized by its low swimming frequency, small bell deformation during the contraction phase, and high Froude efficiency. The critical components of the robot include the flexible bell that provides the overall shape and dimensions of the jellyfish, a central hub and a stage used to provide electrical connections and mechanical support to the actuators, eight distinct spars meant to keep the upper part of the bell stationary, and flexible IPMC actuators that extend radially from the central stage. The bell is fabricated from a commercially available heat-shrinkable polymer film to provide increased shape-holding ability and reduced weight. The IPMC actuators constructed for this study demonstrated peak-to-peak strains of ∼0.7% in water across a frequency range of 0.1–1.0 Hz. By tailoring the applied voltage waveform and the flexibility of the bell, the completed robotic jellyfish with four actuators swam at an average speed 0.77 mm s−1 and consumed 0.7 W. When eight actuators were used the average speed increased to 1.5 mm s−1 with a power consumption of 1.14 W.

Design and Locomotion Control of a Biomimetic Underwater Vehicle With Fin Propulsion

As a novel biologically inspired underwater vehicle, a robotic manta ray (RoMan-II) has been developed for potential marine applications. Manta ray can perform diversified locomotion patterns in water by manipulating two wide tins. These motion patterns have been implemented on the developed fish robot, including swimming by flapping fins, turning by modulating phase relations of fins, and online transition of different motion patterns. The movements are achieved by using a model of artificial central pattern generators (CPGs) constructed with coupled nonlinear oscillators. This paper focuses on the analytical formulation of coupling terms in the CPG model and the implementation issues of the CPG-based control on the fish robot. The control method demonstrated on the manta ray robot is expected to be a frame- work that can tackle locomotion control problems in other types of multifin-actuated fish robots or more general robots with rhythmic movement patterns.

Effects of Cross Section and Flexibility of Pectoral Fins on the Swimming Performance of Biomimetic Underwater Vehicles

Effects of Cross Section and Flexibility of Pectoral Fins on the Swimming Performance of Biomimetic Underwater Vehicles

Swimming locomotion modeling for biomimetic underwater vehicle with two undulating long-fins

SUMMARYA biomimetic underwater vehicle, which is propelled by two undulating long-fins, is introduced in this paper. The undulating or oscillating movements of symmetrical long-fins cause the complex locomotion of biomimetic underwater vehicle. For convenience, three motion modes are proposed and considered firstly. Then an inertial unit is installed for collection of accelerations and angular velocity. The underwater vehicle's MIMO model is reduced into a SISO model by some simplifications. A sine wave function deduced from the long-fin's time-varying membrane is proposed and used as the input of the biomimetic underwater vehicle ARMA model, and velocity or angular velocity is considered as the model output. The algorithms based on recursive weighted least squares are applied for model parameter identification. Experiments carried out with a long-fin propelled underwater vehicle. The experimental results show that the proposed methods can build valid locomotion models for three motion modes efficiently.

Parameter analysis of batoid fin motions using fluid–structure interaction-based simulation and design of experiments

Recently, much attention has been focused on the development of bio-mimetic underwater vehicles with a view to emulate the characteristics and performances of fishes and marine mammals. This study examines the thrust motions of batoids, which have excellent cruise and manoeuvrability characteristics during underwater movement. Numerical results concerning moving distance and velocity derived from batoid fin motions are studied. The commercial software package ADINA is employed for three-dimensional time-dependent fluid–structure interaction analysis. Following the numerical identification of fin motion under the simplified model of an actual cownose ray, a parameter design is performed to predict the optimal levels of fin width, thickness, frequency, and amplitude, and the significant factor effects of these in the design of experiments are discussed. This study also shows that fin frequency has strong interaction with amplitude and width.

Biomimetic Underwater Vehicle Modeling Based on Neural Network

AbstractThis paper introduces the basic control methods of a Biomimetic Underwater Vehicle, and a neural network model is designed for the vehicle. The concerned vehicle is propelled by two undulating long-fins installed on both sides. Ten motors are employed to drive the long-fin and sine wave function is employed for motor control. The real-time control system is designed for controlling the long-fins by adjusting its oscillating frequency and oscillating amplitude to control the yaw angle of the vehicle. A set of inertial sensors is employed for collecting pose information including yaw angle. Analyses show that the yaw angle increment is closely related to the long-fin oscillating frequency, the long-fin oscillating amplitude and the vehicle yaw angle velocity. Hence a neural network with one hidden layer is designed for building a nonlinear MISO model. Based on qualitative hydrodynamic analysis, oscillating frequency of the two long-fins and angular velocity are chosen as the model input. And the yaw angle increment is chosen as the model output. Based on analysis of the experimental thrust data, linear function is used as activation function of the neurons. Finally, experimental data are used for neural network training and validation. The results show that the designed neural network model is valid.

추진력 생성을 위한 가오리 날개 짓의 유체-구조연성 수치해석

Recently, the development of bio-mimetic underwater vehicles that can emulate the characteristic movements of marine fish and mammals has attracted considerable attention. In this study, the motion of the batoid (i.e., cownose ray) fin that facilitates excellent cruising and maneuvering during underwater movement has been studied. The velocity achieved and distance covered with each fin movement are numerically studied. A fluid-structure interaction method is used to perform 3D time-dependent numerical analysis, wherein an adaptive mesh is employed to account for the large deformation of a fin interacting with a fluid. The results of a preliminary study show that the thrust of a ray fin is highly dependent on the frequency. Further, once the fin amplitude required for generating a given thrust is evaluated for the conditions experienced by an actual ray, the frequency and amplitude values for achieving better thrust are determined.

Better Endurance and Load Capacity: An Improved Design of Manta Ray Robot (RoMan-II)

An improved design of a biomimetic underwater vehicle (RoMan-II) inspired by manta ray is presented in this paper. The design of the prototype and the swimming motion control are discussed. Instead of using rigid multiple degree-of-freedom linkages as fin rays in the first version, six flexible fin rays are adopted to drive two sided fins which generate thrust through flapping motions. Furthermore, in order to save the energy for a long distance cruising, a bio-inspired gliding motion is incorporated onto the motion control of the improved prototype. With a closed-loop buoyancy control system, the vehicle can perform gliding locomotion in water, which reduces the overall energy consumption. The vehicle can also perform pivot turning and backward locomotion without turning its body. It can achieve an average velocity of one body length per second. The vehicle is able to carry various sensors or communication equipments, as the payload capacity is about 4 kg. Initial testing shows that the operation time of the buoyancy body is estimated to about 6 hours for free swimming and 90 hours for a pure gliding. The flapping frequency, flapping amplitude, and the number of waves performed across the fin's chord and wave directions can be independently tuned through the proposed control scheme. In general, the present prototype provides a useful platform to study the ray-like swimming motion in a single or combination mode of flapping, undulation and gliding.

Free-Locomotion of Underwater Vehicles Actuated by Ionic Polymer Metal Composites

In this paper, we develop a modeling framework for studying free-locomotion of biomimetic underwater vehicles propelled by vibrating ionic polymer metal composites (IPMCs). The motion of the vehicle body is described using rigid body dynamics in fluid environments. Hydrodynamic effects, such as added mass and damping, are included in the model to enable a thorough description of the vehicle's surge, sway, and yaw motions. The time-varying actions exerted by the vibrating IPMC on the vehicle body, including thrust, lift, and moment, are estimated by combining force and vibration measurements with reduced order modeling based on modal analysis. The model predictions are validated through experimental results on a miniature remotely controlled fish-like robotic swimmer.

Numerical Study on Motion Simulation with Control Algorithm of Biomimetic Underwater Vehicle

This paper describes the numerical simulations of simple motion and motion control of a biomimetic underwater vehicle equipped with two pairs of mechanical pectoral fins. This biomimetic underwater vehicle is called PLATYPUS, which was developed several years ago in Osaka Univ. Practical and accurate control algorithm is necessary to make sure that the underwater vehicle can carry out the prescribed task successfully. For a long time our team has been developing a CFD-based motion simulator with Fuzzy control algorithm. In this paper, firstly motion simulation without control algorithm in still water is given and then motion simulations with distance control and Point-To-Point (PTP) control using Fuzzy control algorithm were described.

Measurement of Environmental Features by an Artificial Lateral Line System for Biomimetic Underwater Vehicles

Measurement of Environmental Features by an Artificial Lateral Line System for Biomimetic Underwater Vehicles