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Robot body design: Isometric exploded view (top), isometric view (bottom left), front view (bottom right). All views show the robot upside down to facilitate part visualization.
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This paper presents our latest results in the development of biomimetic batoid robots. Our goal is to utilize these robots for autonomous environmental exploration and monitoring missions in coastal environments. These new robots will be part of a larger heterogeneous robotic network already being developed by our group which combines traditional r...
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... on a soft polymer body and mimics the morphology and kinematics of rajiform or undulatory batoids (i.e. stingrays). A rigid shell embedded inside the body is used to house all the components the robot needs for locomotion and autonomy. The components include actuators, batteries, a buoyancy tank, and the control and communication electronics. Fig. 1 shows different views of the robot design and all its components. The robot features are explained in the following ...
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... the robot's body is rigid. This feature enables embedding com- ponents inside the robot without modifying its kinematics. In order to maximize the space inside the shell, it was designed to reproduce the shape of the outer surface of the body (Fig. 2). For convenience, the shell was composed of several parts (three in total) (parts 2,5 and 6 in Fig. 1) manufactured using a 3D-printer. This process is fast, enables us to create complex shapes without difficulties, and it is repeatable. The shell was coated with epoxy to strengthen its structure and seal any gaps between the parts. A flat carbon-fiber cover closes the shell. This cover is made in two parts (parts 19 and 20 in Fig. 1). ...
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... 2,5 and 6 in Fig. 1) manufactured using a 3D-printer. This process is fast, enables us to create complex shapes without difficulties, and it is repeatable. The shell was coated with epoxy to strengthen its structure and seal any gaps between the parts. A flat carbon-fiber cover closes the shell. This cover is made in two parts (parts 19 and 20 in Fig. 1). The smaller part gives access to a box inside the shell that contains the connectors for the batteries and the controllers. That way, only a small portion of the body needs to be cut open to access the inner components. The induced hole can be refilled easily by adding silicone at this ...
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... controlled through serial communications and they can provide position feedback. They also have temperature and load sensors which can detect an abnormal use of the motors. Two Robotis EX-106 were chosen to actuate the two pectoral fins and one Robotis RX-28 actuates the buoyancy tank. An exploded view of the actuation of the fin can be seen on Fig. 1 (parts 9 to 12), as well as its implementation on the shell. 3) Buoyancy tank: A buoyancy tank allows depth change control and can be used to complement swimming motions. The tank is composed of four syringes; for a total volume of 0.18 liters. As it represents only 3% of the total volume of the robot, the mass of the robot needs to be carefully ...
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Citations
... These early AUVs were often simple in design, using basic propellers and fins to move through the water [19]. For instance, in [20] a biomimicry model is developed using stingrays as its incitement. Similarly, in [21], authors took inspiration from Leptocephalus (Eel Larva) for its soft robot model. ...
Autonomous Underwater Vehicles (AUVs) epitomize a revolutionary stride in underwater exploration, seamlessly assuming tasks once exclusive to manned vehicles. Their collaborative prowess within joint missions has inaugurated a new epoch of intricate applications in underwater domains. This study’s primary aim is to scrutinize recent technological advancements in AUVs and their role in navigating the complexities of underwater environments. Through a meticulous review of literature and empirical studies, this review synthesizes recent technological strides, spotlighting developments in biomimicry models, cutting-edge control systems, adaptive navigation algorithms, and pivotal sensor arrays crucial for exploring and mapping the ocean floor. The article meticulously delineates the profound impact of AUVs on underwater robotics, offering a comprehensive panorama of advancements and illustrating their far-reaching implications for underwater exploration and mapping. This review furnishes a holistic comprehension of the current landscape of AUV technology. This condensed overview furnishes a swift comparative analysis, aiding in discerning the focal points of each study while spotlighting gaps and intersections within the existing body of knowledge. It efficiently steers researchers toward complementary sources, enabling a focused examination and judicious allocation of time to the most pertinent studies. Furthermore, it functions as a blueprint for comprehensive studies within the AUV domain, pinpointing areas where amalgamating multiple sources would yield a more comprehensive understanding. By elucidating the purpose, employing a robust methodology, and anticipating comprehensive results, this study endeavors to serve as a cornerstone resource that not only encapsulates recent technological strides but also provides actionable insights and directions for advancing the field of underwater robotics.
... It is driven by a soft fluidic actuator and has a buoyancy control unit for depth adjustment. Other marine creatures such as batoids were also mimicked, as in the case of the stingray robot with a soft silicone outer body and pectoral fins [41]. ...
Nature and biological creatures are some of the main sources of inspiration for humans. Engineers have aspired to emulate these natural systems. As rigid systems become increasingly limited in their capabilities to perform complex tasks and adapt to their environment like living creatures, the need for soft systems has become more prominent due to the similar complex, compliant, and flexible characteristics they share with intelligent natural systems. This review provides an overview of the recent developments in the soft robotics field, with a focus on the underwater application frontier.
... However, a high number of actuators can cause an increase in control complexity, an increase of power consumption, and a low mean-time-to-failure value [14]. An advantage strategy adopted by Valdivia Y Alvarado whose robotic stingrays are made out of a soft material and only require one actuator per fin [15], [16], [17], [18]. Chew et al. presented a prototype of the Robot Manta Ray in which the oscillatory motion of each fin is controlled by only one servo motor [19]. ...
... The fin structure mimics the lepidotrichia of rayfinned fishes [?]. The passive waveform reduces the complexity of the actuation and is less susceptible to mechanical failure [17]. The robot has a body length of 180 mm and weighs 310 g. ...
Batoids use their large pectoral fins to achieve unique maneuverability and propulsive performance. In this work, the design, fabrication and characterization a soft batoid-like robot is presented. The robot is designed to mimic un-dulatory rajiform locomotion. The design is under-actuated, simple and robust and well suited for propulsive performance experiments thanks to its full autonomy, long battery life, and wireless recharging capabilities. The robot has a 180mm body length, a maximum flapping amplitude of 60deg, and reaches a peak speed of 0.93 body length per second. In order to characterize its swimming kinematics and propulsive forces a special setup was built using an instrumented holder and high speed video. Experiments were conducted to characterize propulsive force generation with varying fin flapping frequencies (from 1hz to 2. 4hz), amplitudes, and wavelengths. The results show that while both flapping frequency and amplitude influence propulsive forces, for the locomotion modes tested, flapping frequency has a stronger effect on both thrust and side forces. Furthermore, larger side forces than thrust forces are produced for the same swimming parameters.
... However, a high number of actuators can cause an increase in control complexity, an increase of power consumption, and a low mean-time-to-failure value [14]. An advantage strategy adopted by Valdivia Y Alvarado whose robotic stingrays are made out of a soft material and only require one actuator per fin [15], [16], [17], [18]. Chew et al. presented a prototype of the Robot Manta Ray in which the oscillatory motion of each fin is controlled by only one servo motor [19]. ...
... The fin structure mimics the lepidotrichia of rayfinned fishes [?]. The passive waveform reduces the complexity of the actuation and is less susceptible to mechanical failure [17]. The robot has a body length of 180 mm and weighs 310 g. ...
... II. RELATED WORK Almost 15 years ago, the first biometric robot was introduced [2]. The first machines that can reproduce the movement of a fish to design an underwater robot was introduced at MIT. ...
A possible solution to minimize the delay in rescuing the coastal areas’ ships accident and useful kit for underwater research has been illustrated in this paper. An underwater research and rescue robot has been designed, tested and analyzed for the coast guards and rescue team to save lives. This robot may also be used in research work since Bangladesh has a very large coastal boarder in the Bay of Bengal. Researchers may find this robot useful while doing their research to utilize the resources covered up beneath the Bay of Bengal. However, the robot can also be used in the personal research work. A raspberry pi is used as the communication and control device in this project. Pi camera has been used to get live video streams from the robot to the user. The raspberry pi is directly connected to a router which is in the same network of the central computer via Ethernet cable. User can send command from the computer to raspberry to navigate the robot and also can get the live video stream from the robot. Navigation is controlled by the Brushless motors via Electronic Speed Control (ESC).
... A fifth mechanism, used in a batoid robot, also compresses air through a piston. Although smaller than the fourth system, it still has bulky external actuation parts (such as a lead screw drive) that protrude from the main body of the robot and are difficult to incorporate in other designs such as submarines or robotic fish (49). By using similar principles to this fifth mechanism but further miniaturizing the actuation, we designed a modular buoyancy system that is fast, simple, and effective in actuation and control. ...
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.
... A fifth mechanism, used in a batoid robot, also compresses air through a piston. While smaller than the fourth system, it still has bulky external actuation parts, such as a lead screw drive that protrudes from the main body of the robot, and is difficult to incorporate in other designs like submarines or robotic fish [Cloitre et al., 2012]. By using similar principles as this fifth mechanism but further miniaturizing the actuation, we designed a modular buoyancy system that is fast, simple, and effective in actuation and control. ...
This thesis describes the creation and control of soft robots made of deformable elastomer materials and powered by fluidics. We embed soft fluidic actuators into self-contained soft robotic systems, such as fish for underwater exploration or soft arms for dynamic manipulation. We present models describing the physical characteristics of these continuously deformable and fully soft robots, and then leverage these models for motion planning and closed-loop feedback control in order to realize quasi-static manipulation, dynamic arm motions, and dynamic interactions with an environment. The design and fabrication techniques for our soft robots include the development of soft actuator morphologies, soft casting techniques, and closed-circuit pneumatic and hydraulic powering methods. With a modular design approach, we combine these soft actuator morphologies into robotic systems. We create a robotic fish for underwater locomotion, as well as multi-finger hands and multi-segment arms for use in object manipulation and interaction with an environment. The robotic fish uses a soft hydraulic actuator as its deformable tail to perform open-loop controlled swimming motions through cyclic undulation. The swimming movement is achieved by a custom-made displacement pump and a custom-made buoyancy control unit, all embedded within the soft robotic fish. The fish robot receives high-level control commands via acoustic signals to move in marine environments. The control of the multi-segment arms is enabled by models describing the geometry, kinematics, impedance, and dynamics. We use the models for quasi-static closed-loop control and dynamic closed-loop control. The quasi-static controllers work in combination with the kinematic models and geometric motion planners to enable the soft arms to move in confined spaces, and to autonomously perform object grasping. Leveraging the models for impedance and dynamics, we also demonstrate dynamic arm motions and end-effector interactions of the arm with an environment. Our dynamic model allows the application of control techniques developed for rigid robots to the dynamic control of soft robots. The resulting model-based closed-loop controllers enable dynamic curvature tracking as well as surface tracing in Cartesian space.
... In such sensors, applied external stresses lead to changes in resistance. The interest in this type of materials has increased significantly since they can be integrated into soft robots [6][7] [8], wearable electronics [9] [10], textiles [11] [12] and fabrication of flexible electronics [13] [14]. Materials such as eutectic gallium indium (eGaIn) [4] [12] [13], carbon [3] [5], and ionic fluids [15] have been studied. ...
... The shell is embedded in a soft polymer body that has the shape of a Stingray. Figure 4.17 shows the robot being tested in a swimming pool [45]. The difference between the Stingray robot and traditional robots is that it's a soft under-actuated robot that does not require a complex assembly of rigid mechanisms to provide all the degrees of freedom needed to enable body motions. ...
... 17 Stingray robot being tested in a swimming pool[45]. Reprinted with permission from IEEE. ...
Aquatic organisms capable of undergoing extensive volume variation of their body during locomotion can benefit from increased thrust production. This is enabled by making use of not only the expulsion of mass from their body, as documented extensively in the study of pulsed-jet propulsion, but also from the recovery of kinetic energy via the variation of added mass. We use a simplified mechanical system, i.e. a shape-changing linear oscillator, to investigate the phenomenon of added-mass recovery. Our study proves that a deformable oscillator can be set in sustained resonance by exploiting the contribution from shape variation alone which, if appropriately modulated, can annihilate viscous drag. By confirming that a body immersed in a dense fluid which undergoes an abrupt change of its shape experiences a positive feedback on thrust, we prove that soft-bodied vehicles can be designed and actuated in such a way as to exploit their own body deformation to benefit of augmented propulsive forces.
... Third, batoids are increasingly serving as subjects for robotic models of aquatic propulsion (e.g. Blevins and Lauder, 2013;Cloitre et al., 2012;Dewey et al., 2012;Krishnamurthy et al., 2010;Moored et al., 2011a,b;Park et al., 2016), and yet threedimensional biological data on how the wing moves are extremely limited. Such data are needed to provide a template for programming robotic ray wing surface motions, and we aim to provide a new kinematic data set on wing-based aquatic propulsion for this purpose. ...
Most batoid fishes have a unique swimming mode in which thrust is generated by either oscillating or undulating expanded pectoral fins that form a disc. Only one previous study of the freshwater stingray has quantified three-dimensional motions of the wing, and no comparable data are available for marine batoid species that may differ considerably in their mode of locomotion. Here we investigate three-dimensional kinematics of the pectoral wing of the little skate, Leucoraja erinacea, swimming steadily at two speeds (1 and 2 body lengths per second, BL×s(-1)). We measured the motion of nine points in three dimensions during wing oscillation and determined that there are significant differences in movement amplitude among wing locations, as well as significant differences as speed increases in body angle, wing beat frequency, and speed of the traveling wave on the wing. In addition, we analyzed differences in wing curvature with swimming speed. At 1 BL×s(-1), the pectoral wing is convex in shape during the downstroke along the medio-lateral fin midline, but at 2 BL×s(-1) the pectoral fin at this location cups into the flow indicating active curvature control and fin stiffening. Wing kinematics of the little skate differed considerably from previous work on the freshwater stingray, which does not show active cupping of the whole fin on the downstroke.
