Effect of flapping orientation on caudal fin propelled bio-inspired underwater robots
01 Jun 2020-Vol. 9, Iss: 1, pp 55-68
TL;DR: It is found that dorso-ventral flapping could lead to better self-stabilizing effects and lesser energy consumption compared to sideways flapping, and is an appealing advantage for underwater surveying robots carrying cameras and sensors as controlled body oscillations could yield better results from its payloads.
Abstract: Aquatic animals and mammals in nature, in particular, the Body and/or Caudal Fin (BCF) swimmers swim either by flapping their fins in the sideways direction or the dorso-ventral direction. Not much literature is available on the effects of the performance of these robots based on the choice of its flapping orientation. In this research, it is found that dorso-ventral flapping could lead to better self-stabilizing effects and lesser energy consumption compared to sideways flapping. It is also found that the choice of dorso-ventral flapping offers the possibility of controlling the body’s oscillation amplitude while flapping. This is an appealing advantage for underwater surveying robots carrying cameras and sensors as controlled body oscillations could yield better results from its payloads. The main body of results is obtained with simulations for underwater vehicle dynamics with the coefficients of the REMUS underwater vehicle, while stability analysis for a generalised case is also presented.
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TL;DR: In this article , a mathematical modeling and waypoint guidance system for a biomimetic autonomous underwater vehicle (BAUV) is proposed, where the BAUV achieves sideways and dorsoventral thunniform motion by flapping its caudal fin through a parallel mechanism.
Abstract: The performance of biomimetic underwater vehicles directly depends on the correct design of their propulsion system and its control. These vehicles can attain highly efficient motion, hovering and thrust by properly moving part(s) of their bodies. In this article, a mathematical modeling and waypoint guidance system for a biomimetic autonomous underwater vehicle (BAUV) is proposed. The BAUV achieves sideways and dorsoventral thunniform motion by flapping its caudal fin through a parallel mechanism. Also, an analysis of the vehicle’s design is presented. A thrust analysis was performed based on the novel propulsion system. Furthermore, the vehicle’s kinematics and dynamic models were derived, where hydrodynamic equations were obtained as well. Computed models were validated using simulations where thrust and moment analysis was employed to visualize the vehicle’s performance while swimming. For the path tracking scheme, a waypoint guidance system was designed to correct the vehicle’s direction toward several positions in space. To accurately obtain waypoints, correction over the propeller’s flapping frequency and bias was employed to achieve proper thrust and orientation of the vehicle. The results from numerical simulations showed how by incorporating this novel propulsion strategy, the BAUV improved its performance when diving and maneuvering based on the dorsoventral and/or sideways configuration of its swimming mode. Furthermore, by designing proper strategies to regulate the flapping performance of its caudal fin, the BAUV followed the desired trajectories. The efficiency for the designed strategy was obtained by comparing the vehicle’s traveled distance and ideal scenarios of straight-line trajectories between targets. During simulations, the designed guidance system presented an efficiency of above 80% for navigation tasks.
2 citations
TL;DR: In this article , a pneumatic soft-bodied bionic flipper with strong underwater mobility, good environmental adaptability, and flexible attitude transformation is drawn, combined with the large deformation and hyperelastic properties of silicone.
Abstract: The sea lion fore flipper has superior underwater movement performance. Its structural characteristics and propulsion mechanism are drawn, combined with the large deformation and hyperelastic properties of silicone, a pneumatic soft‐bodied bionic flipper with strong underwater mobility, good environmental adaptability, and flexible attitude transformation. Based on Yeoh's second‐order constitutive model of silicone, the nonlinear dynamic analysis of the main limb of the bionic flipper is carried out, and the deformation analysis theoretical model is established. Then, the force analysis of infinitesimal and integral of the wing fin of the bionic flipper is analyzed by the blade element theory, to obtain the theoretical model of underwater propulsion dynamic performance. The superiority of the hydrodynamic performance of the bionic flipper is analyzed and confirmed using the bidirectional fluid–structure coupling numerical simulation algorithm. An experimental test platform is built to test the physical model of the bionic flipper. The motion and dynamic characteristics curves of the bionic flipper are obtained and compared with the corresponding numerical simulation results. The results show that the theoretical model and numerical simulation are accurate, and the structure is feasible, which can provide methods and references for the research and implementation of the underwater propeller.
1 citations
References
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01 Sep 2001
TL;DR: In this article, the authors developed and verified a six degree of freedom, non-linear simulation model for the REMUS vehicle, the first such model for this platform, and the simulator output is then checked against vehicle dynamics data collected in experiments performed at sea.
Abstract: Improving the performance of modular, low-cost autonomous underwater vehicles (AUVs) in such applications as long-range oceanographic survey, autonomous docking, and shallow-water mine countermeasures requires improving the vehicles' maneuvering precision and battery life. These goals can be achieved through the improvement of the vehicle control system. A vehicle dynamics model based on a combination of theory and empirical data would provide an efficient platform for vehicle control system development, and an alternative to the typical trial-and-error method of vehicle control system field tuning. As there exists no standard procedure for vehicle modeling in industry, the simulation of each vehicle system represents a new challenge. Developed by von Alt and associates at the Woods Hole Oceanographic Institute, the REMUS AUV is a small, low-cost platform serving in a range of oceanographic applications. This thesis describes the development and verification of a six degree of freedom, non-linear simulation model for the REMUS vehicle, the first such model for this platform. In this model, the external forces and moments resulting from hydrostatics, hydrodynamic lift and drag, added mass, and the control inputs of the vehicle propeller and fins are all defined in terms of vehicle coefficients. This thesis describes the derivation of these coefficients in detail. The equations determining the coefficients, as well as those describing the vehicle rigid-body dynamics, are left in non-linear form to better simulate the inherently non-linear behavior of the vehicle. Simulation of the vehicle motion is achieved through numeric integration of the equations of motion. The simulator output is then checked against vehicle dynamics data collected in experiments performed at sea. The simulator is shown to accurately model the motion of the vehicle. Thesis Supervisor: Jerome Milgram Title: Professor of Ocean Engineering, MIT Thesis Supervisor: Kamal Youcef-Toumi Title: Professor of Mechanical Engineering, MIT Thesis Supervisor: Christopher von Alt Title: Principal Engineer, WHOI Candide had been wounded by some splinters of stone; he was stretched out in the street and covered with debris. He said to Pangloss: "Alas, get me a little wine and oil, I am dying." "This earthquake is not a new thing," replied Pangloss. "The town of Lima suffered the same shocks in America last year; same causes, same effects; there is certainly a vein of sulfur underground from Lima to Lisbon." "Nothing is more probable," said Candide, "but for the love of God, a little oil and wine." "What do you mean, probable?" replied the philosopher. "I maintain that the matter is proved." Candide lost consciousness.
535 citations
21 Mar 2018
TL;DR: This work presents the design, fabrication, control, and oceanic testing of a soft robot fish that can swim in three dimensions to continuously record the aquatic life it is following or engaging and exhibits a lifelike undulating tail motion enabled by a soft robotic actuator design.
Abstract: Closeup exploration of underwater life requires new forms of interaction, using biomimetic creatures that are capable of agile swimming maneuvers, equipped with cameras, and supported by remote human operation. Current robotic prototypes do not provide adequate platforms for studying marine life in their natural habitats. This work presents the design, fabrication, control, and oceanic testing of a soft robotic fish that can swim in three dimensions to continuously record the aquatic life it is following or engaging. Using a miniaturized acoustic communication module, a diver can direct the fish by sending commands such as speed, turning angle, and dynamic vertical diving. This work builds on previous generations of robotic fish that were restricted to one plane in shallow water and lacked remote control. Experimental results gathered from tests along coral reefs in the Pacific Ocean show that the robotic fish can successfully navigate around aquatic life at depths ranging from 0 to 18 meters. Furthermore, our robotic fish exhibits a lifelike undulating tail motion enabled by a soft robotic actuator design that can potentially facilitate a more natural integration into the ocean environment. We believe that our study advances beyond what is currently achievable using traditional thruster-based and tethered autonomous underwater vehicles, demonstrating methods that can be used in the future for studying the interactions of aquatic life and ocean dynamics.
469 citations
11 Mar 2010
TL;DR: This paper describes and implements a Kalman-based framework, called INS-EKF-ZUPT (IEZ), to estimate the position and attitude of a person while walking, which represents an extended PDR methodology (IEz+) valid for operation in indoor spaces with local magnetic disturbances.
Abstract: The estimation of the position of a person in a building is a must for creating Intelligent Spaces. State-of-the-art Local Positioning Systems (LPS) require a complex sensornetwork infrastructure to locate with enough accuracy and coverage. Alternatively, Inertial Measuring Units (IMU) can be used to estimate the movement of a person; a methodology that is called Pedestrian Dead-Reckoning (PDR). In this paper, we describe and implement a Kalman-based framework, called INS-EKF-ZUPT (IEZ), to estimate the position and attitude of a person while walking. IEZ makes use of an Extended Kalman filter (EKF), an INS mechanization algorithm, a Zero Velocity Update (ZUPT) methodology, as well as, a stance detection algorithm. As the IEZ methodology is not able to estimate the heading and its drift (non-observable variables), then several methods are used for heading drift reduction: ZARU, HDR and Compass. The main contribution of the paper is the integration of the heading drift reduction algorithms into a Kalman-based IEZ platform, which represents an extended PDR methodology (IEZ+) valid for operation in indoor spaces with local magnetic disturbances. The IEZ+ PDR methodology was tested in several simulated and real indoor scenarios with a low-performance IMU mounted on the foot. The positioning errors were about 1% of the total travelled distance, which are good figures if compared with other works using IMUs of higher performance.
460 citations
TL;DR: In this article, a review of biomimetic underwater robots built using smart actuators, e.g., a shape memory alloy (SMA), an ionic polymer metal composite (IPMC), lead zirconate titanate (PZT), or a hybrid SMA and IPMC actuator, is presented.
Abstract: In this paper, biomimetic underwater robots built using smart actuators, e.g., a shape memory alloy (SMA), an ionic polymer metal composite (IPMC), lead zirconate titanate (PZT), or a hybrid SMA and IPMC actuator, are reviewed. The effects of underwater environment were also considered because smart actuators are often affected by their external environment. The characteristics of smart actuators are described based on their actuating conditions and motion types. Underwater robots are classified based on different swimming modes. We expanded our classification to non-fish creatures based on their swimming modes. The five swimming modes are body/caudal actuation oscillatory (BCA-O), body/caudal actuation undulatory (BCA-U), median/paired actuation oscillatory (MPA-O), median/paired actuation undulatory (MPA-U), and jet propulsion (JET). The trends of biomimetic underwater robots were analyzed based on robot speed (body length per second, BL/s). For speed per body length, robots using an SMA as an actuator are faster than robots using an IPMC when considering a similar length or weight. Robots using a DC motor are longer while their speeds per body length are similar, which means that robots using smart actuators have an advantage of compactness. Finally, robots (using smart actuators or a motor) were compared with underwater animals according to their speed and different swimming modes. This review will help in setting guidelines for the development of future biomimetic underwater robots, especially those that use smart actuators.
297 citations
Book•
28 Sep 2007
TL;DR: Flight Dynamics Principles is a student focused text that provides easy access to all three topics in an integrated modern systems context and provides a secure foundation from which to move on to more advanced topics such as, non-linear flight dynamics, flight simulation, handling qualities and advanced flight control.
Abstract: The study of flight dynamics requires a thorough understanding of the theory of the stability and control of aircraft, an appreciation of flight control systems and a grounding in the theory of automatic control. Flight Dynamics Principles is a student focused text and provides easy access to all three topics in an integrated modern systems context. Written for those coming to the subject for the first time, the book provides a secure foundation from which to move on to more advanced topics such as, non-linear flight dynamics, flight simulation, handling qualities and advanced flight control. About the author: After graduating Michael Cook joined Elliott Flight Automation as a Systems Engineer and contributed flight control systems design to several major projects. Later he joined the College of Aeronautics to research and teach flight dynamics, experimental flight mechanics and flight control. Previously leader of the Dynamics, Simulation and Control Research Group he is now retired and continues to provide part time support. In 2003 the Group was recognised as the Preferred Academic Capability Partner for Flight Dynamics by BAE SYSTEMS and in 2007 he received a Chairman's Bronze award for his contribution to a joint UAV research programme. New to this edition: * Additional examples to illustrate the application of computational procedures using tools such as MATLAB , MathCad and Program CC . * Improved compatibility with, and more expansive coverage of the North American notational style. * Expanded coverage of lateral-directional static stability, manoeuvrability, command augmentation and flight in turbulence. * An additional coursework study on flight control design for an unmanned air vehicle (UAV).
226 citations