Techniques are disclosed for providing retractable control fins on an underwater vehicle. The retractable control fins can be extended away from a main hull portion of the underwater vehicle and retracted inwards to a stowage region within the hull portion to protect the fins from damage and reduce an overall outer diameter (e.g., in the case of a cylindrical body) of the underwater vehicle. In some embodiments, the control fins are folded inwards to reduce the vehicle diameter. In other embodiments, the control fins are pulled inwards using a rotating structure designed to slide the control fins through an opening and into an inner portion of the hull to reduce the vehicle diameter. The retraction of the fins through the various retraction mechanisms reduces the envelope diameter of the underwater vehicle.

A submarine apparatus includes an internal bellows pipe that compresses and decompresses as the apparatus descends into and ascends within a water current. When the device is in a rising pressure process, water may condense inside a tube which may be collected in a tank. Water may also be condensed due to cold temperatures of the surrounding water and relative warmer air inside the AWS. The water may be used as a fresh source of water for drinking. Some embodiments include a generator assembly that generates electricity from a propellor move within the current. The electricity may be routed to powered components in the apparatus.

A submarine apparatus includes an internal bellows pipe that compresses and decompresses as the apparatus descends into and ascends within a water current. When the device is in a rising pressure process, water may condense inside a tube which may be collected in a tank. Water may also be condensed due to cold temperatures of the surrounding water and relative warmer air inside the AWS. The water may be used as a fresh source of water for drinking. Some embodiments include a generator assembly that generates electricity from a propellor move within the current. The electricity may be routed to powered components in the apparatus.

A vehicle comprising a morphing wing and a body is disclosed. The aircraft is configured to transform from a first configuration into a second configuration for ascent or descent of the aircraft. The drag force and lift force on the aircraft in the second configuration are less than in the first configuration. Transforming from the first to the second configuration comprises: contracting the wing within a geometric plane defined by the wing, and rotating the outer edge of the wing downwards, out of the geometric plane.

An unmanned undersea vehicle including a magnetic coupler drive. The magnetic coupler drive is incorporated into a hull section, such as a tail section of the unmanned undersea vehicle. The magnetic coupler drive includes a motor shaft magnet, a titanium housing disposed about the motor shaft magnet, and a propeller shaft magnet magnetically coupled to the motor shaft magnet, but physically separated from the propeller shaft magnet by the titanium housing.

An unmanned undersea vehicle including a magnetic coupler drive. The magnetic coupler drive is incorporated into a hull section, such as a tail section of the unmanned undersea vehicle. The magnetic coupler drive includes a motor shaft magnet, a titanium housing disposed about the motor shaft magnet, and a propeller shaft magnet magnetically coupled to the motor shaft magnet, but physically separated from the propeller shaft magnet by the titanium housing.

A watercraft comprises a motor, an inertial mass, and a fin. The motor oscillates the inertial mass about an axis, producing a torque reaction on and oscillation of the motor. Oscillation of the motor is communicated to the fin, producing thrust. The system can be operated in reverse, to generate electric power when the system is in a flowing stream of thrust fluid.

A pump-less buoyancy engine for an autonomous underwater vehicle (AUV) includes a buoyancy reduction structure without a hydraulic pump for reducing the buoyancy of the AUV to cause the AUV to descend in the water; and a weight dropping structure for dropping prepackaged weights out of the AUV to cause the AUV to ascend in the water, where the AUV moves forward when descending and ascending.

A pump-less buoyancy engine for an autonomous underwater vehicle (AUV) includes a buoyancy reduction structure without a hydraulic pump for reducing the buoyancy of the AUV to cause the AUV to descend in the water; and a weight dropping structure for dropping prepackaged weights out of the AUV to cause the AUV to ascend in the water, where the AUV moves forward when descending and ascending.

The disclosure provides a method and system for hierarchical disturbance rejection depth tracking control of an underactuated underwater vehicle, and the depth tracking of the underactuated underwater vehicle is divided into kinematic layer guidance and dynamic layer pitch tracking. Adaptive line of sight guidance is used in the kinematic layer to convert a depth error into a desired pitch angle and to estimate and compensate an angle of attack to reject disturbance introduced by an unmeasurable true angle of attack. Based on the above, in the dynamic layer, the active disturbance rejection sliding mode pitch tracking method is used to observe a composite disturbance including an unknown dynamic model and an environmental disturbance by using the active disturbance rejection framework. The model is compensated as a unified integral series type, a sliding mode control law is finally designed to resist an observation error, and a control elevator angle is calculated.