A bionic underwater robot for achieving a variety of motions is disclosed. The bionic underwater robot includes a head and one or more tail structures. Each of the one or more tail structures includes one or more joint structures. Each of the one or more joint structures includes a connection plate, and a modular assembly, comprising an upper servo motor, a lower servo motor, and a bevel gear mechanism, is motorized for performing various movement motions of the joint structure. The bevel gear mechanism is integrally formed by an intermediate bevel gear, a first bevel gear, and a second bevel gear. The upper servo motor drives the first bevel gear from a first side of the modular assembly, while the lower servo motor drives the second bevel gear from a second side.

A bionic underwater robot for achieving a variety of motions is disclosed. The bionic underwater robot includes a head and one or more tail structures. Each of the one or more tail structures includes one or more joint structures. Each of the one or more joint structures includes a connection plate, and a modular assembly, comprising an upper servo motor, a lower servo motor, and a bevel gear mechanism, is motorized for performing various movement motions of the joint structure. The bevel gear mechanism is integrally formed by an intermediate bevel gear, a first bevel gear, and a second bevel gear. The upper servo motor drives the first bevel gear from a first side of the modular assembly, while the lower servo motor drives the second bevel gear from a second side.

A robotic eel may comprise a plurality of torque reaction engines, an inertial mass, and a fin. Each of the plurality of torque reaction engines oscillates an inertial mass about an axis, producing a torque reaction on and oscillation of an external shaft. Oscillation of the external shaft bends a beam of the robotic eel. Bending the beam of the robotic eel produces at least one of a traveling or a standing wave in the beam. The traveling wave may be communicated to a second torque reaction of the plurality of torque reaction engines and to the fin, producing thrust.

A robotic eel may comprise a plurality of torque reaction engines, an inertial mass, and a fin. Each of the plurality of torque reaction engines oscillates an inertial mass about an axis, producing a torque reaction on and oscillation of an external shaft. Oscillation of the external shaft bends a beam of the robotic eel. Bending the beam of the robotic eel produces at least one of a traveling or a standing wave in the beam. The traveling wave may be communicated to a second torque reaction of the plurality of torque reaction engines and to the fin, producing thrust.

Provided is a portable foldable aquaplane, comprising a buoyancy device (9), a handle (2), a pedal board (3) and a seat cushion (5), wherein the buoyancy device (9) comprises a head buoyancy component (1) and a body buoyancy component (13); the head buoyancy component (1) is connected to a front end of the body buoyancy component (13) in a foldable manner; the handle (2) is connected to the head buoyancy component (1) via a first telescopic rod (14); and the seat cushion (5) is connected to the body buoyancy component (13) via a second telescopic rod (15). By adjusting the height of the handle (2) and of the seat cushion (5), the aquaplane is not only capable of satisfying the requirements of riding on water in a standing state, but is also capable of satisfying the requirements of riding on water in a sitting state. The foldable structure of the aquaplane makes it easy to carry and store, and same can also provide sports and entertainment for both individuals and multi-players at the same time by means of a connection hook.

A personal watercraft includes a floatation member, a thrust assembly, a steering assembly, and a braking assembly. The assemblies may be actuated either mechanically or electrically. The thrust assembly is human powered, solar powered, or electric powered. The thrust, steering, and braking assemblies can be added after-market to an existing stand-up paddle board (SUP), or built into one or a plurality of SUPs during initial manufacturing. When the thrust assembly is human powered, it is leg or arm powered. When the thrust assembly is leg powered, the legs can move backward and forward in a sliding motion, up and down in a stomping fashion, or move in a loop trajectory. When the thrust assembly is arm powered, the arms can move forward/backward together or separately. The thrust assembly includes one or a plurality of paddles or flippers that are positioned to the side or under the SUP.

A personal watercraft includes a floatation member, a thrust assembly, a steering assembly, and a braking assembly. The assemblies may be actuated either mechanically or electrically. The thrust assembly is human powered, solar powered, or electric powered. The thrust, steering, and braking assemblies can be added after-market to an existing stand-up paddle board (SUP), or built into one or a plurality of SUPs during initial manufacturing. When the thrust assembly is human powered, it is leg or arm powered. When the thrust assembly is leg powered, the legs can move backward and forward in a sliding motion, up and down in a stomping fashion, or move in a loop trajectory. When the thrust assembly is arm powered, the arms can move forward/backward together or separately. The thrust assembly includes one or a plurality of paddles or flippers that are positioned to the side or under the SUP.

A robotic fish includes a front body, a rear body that includes a first segment and a second segment, and a driving unit. The first segment has a front engaging portion projecting toward and pivotally connected to the front body, and a rear engaging portion formed with a recess that recedes toward the front body and pivotally connected to the second segment. The driving unit includes a motor disposed in the front engaging portion, and a shaft extending along a dorsoventral axis and connecting the motor and the rear connecting portion. A ratio of a distance between the shaft and a foremost edge of the front engaging portion to a distance between the foremost edge and an extreme point of the recess ranges from 0.075 to 0.75.

A robotic fish includes a front body, a rear body that includes a first segment and a second segment, and a driving unit. The first segment has a front engaging portion projecting toward and pivotally connected to the front body, and a rear engaging portion formed with a recess that recedes toward the front body and pivotally connected to the second segment. The driving unit includes a motor disposed in the front engaging portion, and a shaft extending along a dorsoventral axis and connecting the motor and the rear connecting portion. A ratio of a distance between the shaft and a foremost edge of the front engaging portion to a distance between the foremost edge and an extreme point of the recess ranges from 0.075 to 0.75.

In one aspect, a device for providing propulsion in water is provided by the present disclosure. The device includes a parallel mechanism including at least five rigid bars and at least five joints, each joint being positioned between two of the rigid bars and configured to allow movement of the at least five rigid bars, a first servo motor coupled to a first rigid bar included in the at least five rigid bars, a second servo motor coupled to a second rigid bar included in the at least five rigid bars, and a controller coupled to the first servo motor and the second servo motor and configured to actuate the first servo motor and the second servo motor according to a predetermined pattern.