4498 results about "Propeller" patented technology

The present disclosure relates generally to flight control of electric aircraft and other powered aerial vehicles. In one embodiment, a method is disclosed, comprising: receiving a descent rate command from a pilot input device, determining a proximity of each propeller of at least two propellers to a vortex ring state; and controlling the aircraft's descent rate to be less than the commanded descent rate when at least one of the at least two propellers is within a first threshold proximity to the vortex ring state.

Disclosed is a turbulent structure of a reactor, the turbulent structure comprising a reactor body (1), a main shaft (2), and a drive assembly (5), wherein the main shaft (2) is rotatably connected to the reactor body (1) and is provided with a shaft rod (201) transversely extending at a bottom end thereof, a transmission member (3) is arranged between the shaft rod (201) and the interior of the main shaft (2), a propeller-type agitator (4) is provided at an output end of the transmission member (3) to drive the propeller-type agitator (4) to rotate, the propeller-type agitator (4) rotates eccentrically around the central axis of the main shaft (2), and the propeller-type agitator (4) is used for propelling fluid upward. The main shaft (2) and the shaft rod (201) drive the propeller-type agitator (4) to perform a circular motion around the axis of the main shaft (2), expanding the area for upward agitation at the bottom, thereby creating a fluid motion inside the reactor body (1) with upward floating on one side and gradual sinking on the other side, resulting in a differential speed between the two sides of the reactor body (1). During rotation, when a blade moves into the differential region of sinking, the upward-floating fluid collides with the sinking fluid, resulting in turbulence.

The invention belongs to the technical field of wind tunnel tests, and particularly relates to a precession simulation device for a spiral flutter wind tunnel test. According to the invention, the design problem of the rotor craft spiral flutter wind tunnel test device is solved, and the key influence parameters and influence rules of the spiral flutter of the aircraft are researched by designing the precession motion simulation device of the rotor craft. Rotation of the rotor wings can be realized in the wind tunnel, and the rotating speed of the rotor wings is adjusted through the motor. Meanwhile, pitching and deflection modal decoupling of the rotating shaft of the rotating system is achieved, and pitching and deflection modal frequencies are independently adjustable; meanwhile, the axis of the pitch axis and the axis of the yaw axis coincide, so that pitching and yaw freedom degree coupling precession motion can be achieved under the effect of gyroscopic moment. Meanwhile, nacelle rotating mass rotational inertia, nacelle weight and mass center position adjustment can be achieved; and finally, the rotating speed of the rotating mass such as the rotor wing and the propeller hub can be adjusted through a speed adjusting motor, matching of the rotating speed and the incoming flow speed is guaranteed, and the spiral flutter state is achieved.

The invention belongs to the cross technical field of the fusion graph attention network and the ship resistance field, and discloses a ship resistance intelligent forecasting method and system, and the method comprises the steps: constructing nodes and edges in a graph attention network, and carrying out the preprocessing of data; designing and improving a loss function; a dynamic weight multi-attention mechanism is established, and attention weights are automatically distributed according to different ship type features; applying a training strategy of an Adam and SGD combined optimizer to obtain a graph attention network model; and carrying out ship resistance prediction evaluation through the dynamic weight map attention network model. By introducing the ship resistance intelligent forecasting method based on the dynamic weight map attention network and the physical constraint, the ship resistance intelligent forecasting method has the advantages of simple structure and clear algorithm, is specially designed for forecasting resistance under different ship types and solving the matching problem of propellers and power devices, shows remarkable innovativeness and practical value, and is suitable for popularization and application. Powerful support is provided for optimization design, energy conservation and emission reduction and safe navigation of the ship.

An aircraft propulsion assembly that has a nacelle with a front opening and a rear opening, a propeller driven by an electric motor, a fuel cell supplying the electric motor with electric current, an inner channel arranged in the nacelle between the front opening and the rear opening. The electric motor and the fuel cell are disposed in the inner channel. A motorized fan is arranged at the rear part so as to draw in the air present in the inner channel and expel it to the outside through the rear opening. A control unit controls the motorized fan. With such an arrangement, the outside air cools the inside of the nacelle and the dihydrogen is evacuated.

The invention discloses an air-ground multi-mode cross-domain robot system with a clutch structure and a control method. The air-ground multi-mode cross-domain robot system comprises a machine body, wings, clutch assemblies and rotor assemblies. The aircraft body drives the connecting rod mechanism through the steering engine to control the bilateral wings to move. Rotor driving motors, wheels and transmission gear sets are integrated on the wings, and motor power can be distributed to wheel driving shafts and propeller shafts. The clutch assembly is connected with a motor and a propeller shaft through a ratchet wheel meshing mechanism, and power on-off control is achieved, in the ground running process, a clutch is separated to stop rotation of a propeller, power is fully output to wheels to serve as driving wheels, and in the flight mode, the clutch is meshed to synchronously drive rotors and the wheels. According to the system, bimodal power distribution is achieved through a single motor, a driving wheel motor does not need to be additionally arranged, the structural complexity is effectively reduced, the moving speed and controllability are remarkably improved through the ground mode propeller static design, the advantage of cross-domain operation is achieved, and the system is suitable for complex task scenes.

The invention discloses an AUV (Autonomous Underwater Vehicle) path tracking method based on predicted line-of-sight angle guidance, which comprises the following steps: acquiring a real-time navigation state through inertial navigation, acoustic positioning and DVL fusion, introducing a fixed time disturbance predictor to estimate a sideslip angle and an ocean current velocity component on line, adaptively adjusting a line-of-sight distance according to transverse error-navigational speed-curvature, and tracking the path of the AUV. Calculating a predicted line-of-sight angle and outputting an expected heading; and then a propeller and a control surface are driven by adopting a fixed time feedback control law, so that track and attitude error fixed time convergence of the under-actuated AUV under the conditions of strong time-varying ocean current and large sideslip is realized. The method does not need a side thruster or an ocean current prior model, is simple in algorithm structure, is suitable for a high-speed high-curvature track, and has the advantages of high speed, high steady-state precision, low energy consumption and high robustness.

A vertical take-off or landing (VTOL) aircraft is disclosed that includes a propulsion system comprising at least four tilting propulsion assemblies and two or more lifting propulsion assemblies. Actuation of the tilting mechanisms can convert the aircraft from a hover configuration, in which all propellers produce thrust generally upward to counteract the aircraft's weight, to a forward flight configuration, in which the four or more tilting propellers produce thrust generally in a forward direction parallel to the fuselage to overcome drag in cruise flight and the lifting propellers produce no thrust or a level of thrust generally less than that required in the hover configuration.

The invention discloses a small crawler wheel wing combined type deformable land-air amphibious reconnaissance robot and a control method thereof. The robot adopts a crawler wheel wing integrated miniaturization design and comprises a control cabin, a left crawler wheel wing system and a right crawler wheel wing system, the crawler wheel wing systems are connected with the control cabin through steering engines, and a flight mode and a ground mode can be stably switched under the driving of the steering engines. In the flight mode, a flight motor of the crawler wheel wing system drives propellers to rotate at a high speed, lift force is provided, and air flight and attitude stability are achieved. In the ground mode, the crawler wheel wing system is adjusted to the ground contact position, the propellers stop working, the ground motor drives the crawler and the driving wheels through the gear set to provide advancing power, the driven wheels assist in supporting, and the stability and obstacle crossing ability in the complex terrain are enhanced. A multi-mode control method based on model predictive control is adopted for the robot, and the multi-mode control method is achieved by establishing control models of a flight mode and a ground mode, constructing a unified state-space equation and a predictive equation, designing a cost function, dynamically switching the control models and coordinating constraint conditions and control targets. And the trajectory tracking precision and the system stability of the robot in the flight mode and the ground mode are ensured.

The invention provides a multi-mode underwater detection robot. The robot comprises a body section assembly formed by connecting a plurality of cabin pipe assemblies and power cabin assemblies in series. Joints between the cabin pipe assemblies are connected through joint connecting pieces (7); a steering engine joint piece (3) is arranged at the joint connecting piece, a propeller propelling device (4) is arranged at the power cabin assembly, and when the underwater posture and the propelling working condition of the robot are adjusted, a steering engine of the steering engine joint piece applies force to the joint connecting piece to change the included angle of the joint connecting piece, so that the body section assembly is twisted, and the posture of the robot is converted into different modes; the propelling direction of the propeller propelling device is changed; the problems that an existing underwater robot is single in mode, incapable of adapting to complex environments, low in energy efficiency, difficult in structure maintenance and poor in function expansion capacity can be solved.

The utility model relates to a foldable propeller and a cross-medium aircraft with the same, the foldable propeller comprises a propeller hub controlled to rotate, a limiting structure arranged at the end part of the propeller hub and a plurality of blades uniformly arranged around the axis of the propeller hub, and each blade is hinged with the propeller hub; the hinged axis between the paddle and the propeller hub is perpendicular to the rotating axis of the propeller hub, and the limiting structure is located at the front end of the propeller hub in the direction of the pulling force generated when the paddle rotates along with the propeller hub; when the propeller hub rotates, the blades hinged to the propeller hub rotate and unfold under the action of centrifugal force to abut against the limiting structure. When the propeller hub stops rotating, the blades hinged to the propeller hub are folded to be close to the rotating axis of the propeller hub due to self weight or fluid resistance in the underwater flight process. The propellers are configured to be of a foldable structural form, so that the propellers are not prone to being impacted by water flow and damaged, meanwhile, turbulent flow generated when the water flow passes through the propellers is reduced, and the speed and stability of the cross-medium aircraft in the underwater flight process are improved.

The invention relates to the technical field of underwater vehicle fault diagnosis, in particular to a multi-mode propeller fault diagnosis method and diagnosis system. Comprising the following steps: collecting and preprocessing multi-modal data; quantizing the quality of the acoustic signal data and the visual signal data obtained in the previous step in real time; constructing a quality sensing gating network model; and training a quality sensing gating network model, and outputting a propeller fault type by using the trained quality sensing gating network model. The characteristics of the low-quality mode are dominated, enhanced and corrected through the characteristics of the high-quality mode, the interaction strength of the depth characteristics is actively controlled in real time from the source quality of signals, and high robustness and accuracy of propeller fault diagnosis can still be kept in a complex and severe environment.

The invention discloses an integrated machining device suitable for a large marine propeller, which comprises a machining adjusting assembly, the machining adjusting assembly is composed of an X-axis moving mechanism, a Y-axis moving mechanism and a Z-axis moving mechanism, one side of the Z-axis moving mechanism is fixedly provided with a rotating mechanism, one end of the rotating mechanism is fixedly connected with a cutting assembly, and the other end of the rotating mechanism is fixedly connected with a cutter; according to the large marine propeller integrated machining device with the automatic machining function and the self-adaptive clamping function, through the integrated multi-axis linkage machining adjusting assembly and the three-dimensional scanner, automatic path planning can be conducted, and automatic operation is achieved; therefore, the dependence on advanced technicians is greatly reduced, the machining efficiency and the product consistency are remarkably improved, and meanwhile, through the collaborative design of the rotatable three-jaw chuck and the center supporting mechanism, simultaneous reliable supporting from the interior and the exterior of the workpiece can be automatically achieved during clamping.

The invention relates to an annular propeller modeling method and device, modeling equipment and a storage medium, and belongs to the technical field of ship propellors.The annular propeller modeling method comprises the steps that a water flow direction serves as a first coordinate axis, and the radial direction of a first blade serves as a second coordinate axis; a propeller hub center under a corresponding first coordinate axis coordinate when the transition section of the first propeller blade and the second propeller blade reaches the maximum radius of the propeller is used as an original point, a third coordinate axis is determined based on a right-hand rule, a three-dimensional coordinate system is established, and the first propeller blade and the second propeller blade are two different propeller blades; under the three-dimensional coordinate system, the thickness angle of each paddle is determined based on the rotating shaft of the two-dimensional airfoil profile of each paddle, and the inflow angle of each paddle is determined based on the thickness angle of each paddle; and modeling the annular propeller based on the thickness angle and the inflow angle of each blade. According to the method, tip smooth transition and section geometric parameter control of the annular propeller are realized on the premise of relatively low calculation complexity.

The invention discloses a method for completing an autonomous deep-sea exploration task by a deep-sea cross-domain unmanned aerial vehicle. The method comprises the following steps: determining a target area; taking off to a specified height from the sea level, receiving a task execution command and then flying to a target area; when the relative distance between the current position and the coordinates of the target area reaches a preset value, descending; when it is detected that the device is contacted with seawater, the device dives through gravity; when it is detected that the set depth is reached, the propeller is restarted, and the detection task is executed; after the detection task is completed, the standby battery is rejected and ascends; after leaving the water surface, rising to a specified height and switching to a homeward flight mode; and when the deep-sea cross-domain unmanned aerial vehicle is within the sight distance range, a manual landing task is executed. The invention further discloses the deep-sea cross-domain unmanned aerial vehicle. According to the unmanned aerial vehicle and the method, autonomous switching operation between an air medium and an underwater medium can be realized, and the unmanned aerial vehicle has the capability of autonomously completing detection and water body sampling in an extreme deep sea environment.

The invention discloses an unmanned aerial vehicle suitable for microwave reconnaissance interference equipment and an equipment antenna arrangement method, and belongs to the field of unmanned aerial vehicles. The unmanned aerial vehicle comprises a fuselage, wings and an empennage. The fuselage comprises a fuselage head, a fuselage body and a fuselage tail. The wings adopt upper single wings and are mounted at the top of the fuselage; the empennage is installed at the tail of the fuselage. The head of the fuselage adopts a nose cover made of wave-transparent materials, a plurality of forward interference antennas are mounted in the nose cover, lateral interference antennas and reconnaissance antenna arrays are mounted on fuselage skins on two sides of a fuselage main body, a plurality of backward interference antennas are mounted in an engine cover made of wave-transparent materials at the tail of the fuselage, and propellers at the tail end of the unmanned aerial vehicle are made of wave-transparent materials. Through the conformal design of the unmanned aerial vehicle and the antenna, the influence of the antenna on the aerodynamic performance of the unmanned aerial vehicle is reduced to the maximum extent, the aerodynamic layout of the unmanned aerial vehicle is optimized by combining the antenna arrangement, and the task antenna is not shielded.

The invention discloses a cascaded auto-disturbance rejection rotating speed stability control method with a quasi-resonance link based on propeller load, and the method comprises the following steps: S1, building a speed ring mathematical equation containing disturbance according to the basic structure and working principle of a surface-mounted permanent magnet synchronous motor; s2, according to aerodynamic characteristics of the propeller, establishing a mathematical model of tension and load torque of the propeller; s3, establishing a quasi-resonance cascade active-disturbance-rejection speed controller containing disturbance compensation according to the S1 and the S2, and performing stability analysis on a cascade expansion observer equation according to a Lyapunov stability theorem; and S4, a cascade active disturbance rejection control method with a quasi-resonance link is used to realize suppression of periodic and non-periodic disturbance of the rotating speed so as to realize high-performance speed control. According to the method, the motor and the propeller are integrally modeled, the influence of periodic disturbance and non-periodic disturbance on the rotating speed is considered at the same time, and the method has better dynamic performance and steady-state performance.

The utility model discloses a meteorological operation folding wing unmanned aerial vehicle which comprises a hollow fuselage, a nose cover, an electronic speed controller, a propeller, a front wing, a rear wing, a driving motor, a vertical fin, a battery, a flight control navigator, a communication module, an antenna module and a meteorological operation consumable device. The machine head cover is fixed to the head end of the machine body, and the electronic speed controller is fixed to the machine head cover. The propeller is fixed to the end, away from the fuselage, of the nose cover. The front wings are arranged above the head end of the fuselage and are rotationally connected with the fuselage; the vertical tails are arranged on the two opposite sides of the tail end of the fuselage and rotationally connected with the fuselage. The rear wing is arranged below the tail end of the fuselage and is rotationally connected with the fuselage; the driving motor is connected with the propeller; the electronic speed controller is electrically connected with the driving motor and the battery, and the electronic speed controller is used for providing electric power for driving the driving motor to rotate. The folding-wing unmanned aerial vehicle for meteorological operation can improve the effect of artificial rainfall.

The underwater cleaning robot for the net cage and the netting comprises a robot central frame, a thrust propeller, a side thrust propeller, crawler wheels, an underwater camera, a tensioning wheel and a water jet cleaning mechanism, the water jet cleaning mechanism comprises a cleaning disc, an adjuster machine body, a water inlet pipe, a water spraying pipe and a petal-shaped cavitation spray head, and the underwater camera collects netting shaking data; after compensation thrust is calculated through feedback, a thrust propeller provides compensation force to counteract shaking of the netting, a tensioning wheel can tension the netting, the robot can be more effectively attached to the net face, in the walking process of the robot, an external high-pressure pump can pump high-pressure water into a regulator machine body through a water inlet pipe, and therefore the net face can be more effectively attached to the net face. The jet flow is sprayed out through the water spraying pipe and the petal-shaped cavitation nozzles to clean the netting, the petal-shaped cavitation nozzles on the two sides incline towards different sides, the sprayed petal-shaped cavitation fluid can drive the regulator body to rotate, rotary cleaning is achieved, and the cleaning area range and cleanliness of the jet flow are improved.

The invention discloses an embedded fiber grating sensor self-calibration strain monitoring system and method.The system comprises a fiber grating sensor, an optical fiber demodulator and a stress buffering type self-calibration mechanism, and the fiber grating sensor is embedded into a propeller blade prefabricated mounting groove through a metal embedded part and a gradient modulus adhesive layer; the plurality of fiber grating sensors are symmetrically distributed in a propeller blade prefabricated mounting groove in pairs, and infrared rays of each pair of symmetrical fiber grating sensors are converged at the circle center of a propeller hub to form a dynamic reference point; the optical fiber demodulator is integrated on the propeller hub and is connected with the plurality of optical fiber grating sensors; the stress buffering type self-calibration mechanism integrates a double-shaft flexible hinge and a shape memory alloy, and interface stress buffering and fiber grating sensor position collaborative self-calibration are achieved. The interface stress is effectively reduced through the gradient modulus glue layer, and the shape memory alloy drives the double-shaft flexible hinge to efficiently correct the offset of the fiber grating sensor in real time and buffer the vibration.

The helicopter rotor head structure comprises a propeller hub, a propeller clamp, a bearing and a variable pitch mechanism, the propeller hub is arranged at the top of a rotor main shaft, a connecting shaft is arranged in the propeller hub, the end of the connecting shaft extends out of the propeller hub, the end of the connecting shaft is sleeved with the bearing, and the end, away from blades, of the propeller clamp is sleeved with the bearing and rotationally connected with the connecting shaft; the bearings comprise an angular contact bearing, a thrust roller bearing and a deep groove ball bearing, and the angular contact bearing, the thrust roller bearing and the deep groove ball bearing are sequentially arranged in the length direction of the connecting shaft; and the variable-pitch mechanism is arranged on the rotor wing main shaft in a sleeving manner and is connected with the propeller clamp. The bearing has the technical effects that the angular contact bearing, the thrust roller bearing and the deep groove ball bearing are combined for use, so that the axial and radial bearing capacities of the whole bearing are obviously improved, the bearing is not easy to damage, and the whole service life is longer; and by arranging the variable pitch mechanism, the angle of the paddle can be flexibly adjusted, so that the lift force and the resistance generated by the rotor wing are adjusted.

Systems and methods for controlling a variable-pitch propeller of an aircraft are provided. A method for controlling the variable-pitch propeller includes using a feedback controller, operating the variable-pitch propeller at a current operating condition including a current rotational speed, determining a speed error between the current rotational speed of the variable-pitch propeller and a set point rotational speed for the variable-pitch propeller, determining a gain for the feedback controller based on a power coefficient and an advance ratio of the variable-pitch propeller. Using the feedback controller, a propeller pitch command is determined based on the speed error and using the gain. The pitch of the variable-pitch propeller is adjusted according to the propeller pitch command to reduce the speed error.

The invention belongs to the technical field of aviation electric propulsion, and relates to a hydrogen fuel cell superconducting hybrid electric propulsion system based on hydrogen and helium heat exchange cooling, which is suitable for megawatt level branch aircrafts and comprises a liquid hydrogen storage tank, a hydrogen and helium heat exchanger, a hydrogen fuel cell, a lithium battery, an inverter, a superconducting motor, a propeller and other core components. The liquid hydrogen storage tank vaporizes liquid hydrogen through the micro-channel plate type hydrogen-helium heat exchanger and stably supplies the vaporized liquid hydrogen to the hydrogen fuel cell to generate electric energy; helium is used for a low-temperature cooling loop and cooling key assemblies such as a superconducting motor, a low-temperature inverter, a superconducting cable and a hydrogen fuel cell, and it is ensured that the key assemblies stably operate at the optimal working temperature. The hydrogen fuel cell and the lithium battery cooperatively provide electric energy for the superconducting electric propulsion system, the integrated energy management controller dynamically adjusts the output power of the fuel cell and the lithium battery by adopting a state machine strategy, and accurate monitoring and optimal distribution of working parameters of all components are achieved. The optimal heat balance and power output are ensured to be realized in different flight stages such as takeoff, cruise and landing; according to the hydrogen fuel cell hybrid electric propulsion system based on hydrogen and helium heat exchange cooling, the power generation efficiency and the operation stability of the hydrogen fuel cell are remarkably improved, the overall energy conversion efficiency is improved, and the high-power and high-efficiency power extraction requirements of megawatt aircrafts are fully met.

The invention belongs to the technical field of mechanical transmission, and discloses a conductor ring and magnetic resistance array composite permanent magnet thrust bearing and a damping force calculation method. The conductor ring and magnetic resistance array combined type permanent magnet thrust bearing realizes the bearing of non-contact magnetic thrust through the combination of the eddy current ring and the magnetic group array. When thrust from a propeller at the stern end of a propulsion shafting acts, the rotor magnetic group array axially moves, axial traction force is generated between the rotor magnetic group array and the stator magnetic resistance array to counteract the thrust action from the axial direction, meanwhile, the magnetic group array cuts the vortex ring, induction damping is generated on the surface of the vortex ring, damping force is formed, and the vortex ring is driven to rotate. And therefore, the longitudinal vibration during transmission of the propulsion shafting is reduced, and the propulsion shafting system is more silent and stable during operation. In addition, the damping force calculation method does not need complex three-dimensional structure modeling and grid division, is simple in solution, high in universality and short in calculation time consumption, and has high engineering application practical value.

The invention discloses a propeller rotor hovering numerical simulation method. According to the method, the efficiency and the intelligent level of aerodynamic characteristic analysis are remarkably improved. A traditional method depends on physical experiments or high-cost numerical simulation and is difficult to quickly respond to the design requirement of multi-parameter combination, however, according to the method, through virtual geometric parameterization and construction of a structured database, direct mapping is established between macroscopic geometric characteristics of a propeller rotor and aerodynamic response. The neural network model based on artificial intelligence can extract implicit laws from mass simulation data, millisecond prediction of aerodynamic characteristics is achieved, and the time-consuming process of grid division and iterative solution in traditional computational fluid mechanics simulation is avoided. According to the technical breakthrough, designers can rapidly evaluate the performance of different geometric configurations in the early stage, the research and development period is shortened, and meanwhile an efficient tool is provided for parameter sensitivity analysis under the complex working condition.

The present invention relates to a hybrid flying and driving robot comprising a plurality of wheels; a plurality of propellers; a plurality of motors, each of which is configured to drive the rotation of a respective wheel of said plurality of wheels; wherein each respective motor of said plurality of motors is connected to a respective propeller of said plurality of propellers by means of a respective gear arrangement; wherein each respective gear arrangement is rearrangeable between two configurations: a) a first configuration wherein the respective motor is configured to drive the rotation of the respective propeller; b) a second configuration wherein the respective motor does not drive the rotation of the respective propeller.

A propulsion unit, and an aircraft, with a propeller and electric motor, including at least one intermediate element interposed between the electric motor and the propeller and configured to transmit at least thrust loads generated by the propeller, a primary structure supporting the propulsion unit, at least one interface having: a first load path, configured to transmit loads perpendicular to the axis of rotation of the propeller, linking the at least one intermediate element to a support linked rigidly to or incorporated in the primary structure, a second load path, configured to transmit loads that are parallel to the axis of rotation of the propeller, linking the at least one intermediate element to a support linked rigidly to or incorporated in the primary structure.

An electrical propulsion system comprises an inverter, an electrical motor assembly, an assembly, and a rotor position sensor. The inverter comprises a printed circuit board assembly (PCBA). The electrical motor assembly comprises a stator and a rotor. The assembly is configured to rotate a propeller and comprises a moving component and a stationary component. The rotor position sensor comprises at least one sensor coupled to the PCBA, and a magnet located on the moving component. The at least one sensor is configured to detect a magnetic field of the magnet through the stationary component.

A modular vertical take-off and landing aircraft for transporting persons and / or loads, comprising a flight module with multiple drive units arranged on a supporting framework structure, each drive unit having an electric motor and a propeller operatively connected to the electric motor, a transport module having a conveying pod and a connection device for connecting the conveying pod to the flight module. The connection device has an elongated shaft, one end of which is attached to the conveying pod, and a coupling device for connecting the flight module to another end of the elongate shaft of the transport module.

A station keeping waterfowl system includes at least one self propelled station keeping waterfowl decoy and a homing buoy each having water resistant housings, with at least a portion of the decoy housing having a form of a waterfowl. The decoy and buoy each include batteries, microprocessors, and power switches. The decoy includes a motor driven propeller, a motor driven rudder, and a receiving array of antennae for radio direction finding and radio ranging to the buoy. The receiving array is a T-array of antennae comprising a first transverse linear array and a second longitudinal linear array. The homing buoy emits a homing signal and the one or more waterfowl decoys autonomously navigate to remain within a predetermined radius around the buoy. The system includes a simple handheld controller which preferably comprises no more than two switches or buttons.