Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C39/00—Aircraft not otherwise provided for
  • B64C39/02—Aircraft not otherwise provided for characterised by special use
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
  • B64C11/46—Arrangements of, or constructional features peculiar to, multiple propellers
  • B64C11/48—Units of two or more coaxial propellers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C15/00—Attitude, flight direction, or altitude control by jet reaction
  • B64C15/02—Attitude, flight direction, or altitude control by jet reaction the jets being propulsion jets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C39/00—Aircraft not otherwise provided for
  • B64C39/02—Aircraft not otherwise provided for characterised by special use
  • B64C39/024—Aircraft not otherwise provided for characterised by special use of the remote controlled vehicle type, i.e. RPV
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C39/00—Aircraft not otherwise provided for
  • B64C39/06—Aircraft not otherwise provided for having disc- or ring-shaped wings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C39/00—Aircraft not otherwise provided for
  • B64C39/06—Aircraft not otherwise provided for having disc- or ring-shaped wings
  • B64C39/062—Aircraft not otherwise provided for having disc- or ring-shaped wings having annular wings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
  • B64D35/00—Transmitting power from power plants to propellers or rotors; Arrangements of transmissions
  • B64D35/04—Transmitting power from power plants to propellers or rotors; Arrangements of transmissions characterised by the transmission driving a plurality of propellers or rotors
  • B64D35/06—Transmitting power from power plants to propellers or rotors; Arrangements of transmissions characterised by the transmission driving a plurality of propellers or rotors the propellers or rotors being counter-rotating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U30/00—Means for producing lift; Empennages; Arrangements thereof
  • B64U30/20—Rotors; Rotor supports
  • B64U30/26—Ducted or shrouded rotors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
  • B64U50/00—Propulsion; Power supply
  • B64U50/10—Propulsion
  • B64U50/13—Propulsion using external fans or propellers
  • B64U50/14—Propulsion using external fans or propellers ducted or shrouded

Definitions

• the invention relates to Unmanned Aerial Vehicle (UAV) with soft arm propulsion vectoring, which is particularly suitable to safely navigate around obstacles and prevent damage.
• UAV Unmanned Aerial Vehicle
• This is achieved by the flexible arms of this UAV, which are designed to bend upon collision with obstacles. The bending of the arms cushions the impact, reducing the likelihood of damage to the UAV and its surroundings. The compliant nature of the arms actively decelerates the speed of contact, reducing the force of the collision.
• the propeller is housed in a cylindrical shroud above the arms, wherein the shroud acts as a ducted fan and enhances thrust efficiency and also acts as a safety guard against collisions with the environment, the contact of the propeller with small wires, branches, grass or other objects is thereby avoided.
• Rigid frame vertical takeoff and landing (VTOL) unmanned aerial vehicles with multiple planar propellers are widely used for a variety of applications, including remote sensing, package delivery, surveillance, and more.
• UAVs unmanned aerial vehicles
• These UAVs are capable of hovering in one place, precisely controlling their position, and flying with high agility in environments with obstacles.
• their rigid frames and exposed fast-moving propellers pose a threat to people in the vicinity.
• contact with obstacles often leads to a crash as it stops one or more motors.
• Propeller guards can prevent this only in case of low-speed contacts and are unable to prevent small wires, branches, or grass from becoming entangled in the propellers.
• Present invention relates to unmanned aerial vehicle (UAV), which is particularly suitable to be used in environment where safety and maneuverability is the main priority.
• UAV unmanned aerial vehicle
• the UAV is provided with at least two coaxial counter-rotating motors and at least a pair of propellers placed above each other that can be individually controlled, thereby providing control in yaw through change in the sum of produced torques.
• Propellers are housed in a main body represented by a shroud having substantially cylindrical inner opening, ideally strictly cylindrical opening with minimal gap between the inner wall of the shroud and tip of the propellers, thus providing maximum thrust.
• the shroud in combination with the propellers acts as a ducted fan and enhances thrust efficiency and also acts as a safety guard against collisions with the environment.
• the Inertial Measurement Unit IMU is essential for stabilization, continuously reading linear accelerations and angular velocities used for calculating required moments and forces necessary for stabilization.
• the shroud shall be as lightweight as possible while maintaining torsional rigidity due to forces exerted by the moving parts, i.e. the propellers. Naturally, the contact between the inner wall of the shroud and the propellers must be avoided. [0009] In one embodiment, the shroud is advantageously made of a combination of stiff lightweight supporting structure which is internally sheathed with a layer of lightweight material.
• the supporting structure of the shroud is made of carbon tubes or skeleton made by 3D printing, whereas the sheathing layer is made of flexible latex sleeve.
• the UAV according to this invention is further provided with at least three arms mounted symmetrically to each other under the casing through which air is thrusted by propellers.
• the flexible arms of present UAV are designed to bend upon collision with obstacles, providing several benefits and technical effects in terms of safety and stability. Firstly, the bending of the arms cushions the impact, reducing the likelihood of damage to the UAV and its surroundings. Secondly, the compliant nature of the arms actively decelerates the speed of contact, reducing the force of the collision. Additionally, the bending of the arms creates a momentum that rotates the UAV away from the obstacle, preventing further damage and enabling the UAV to resume flight without interruption. The combination of these factors results in particular suitability of employing these arms in combination with other elements of present UAV for navigating through challenging environments, such as tight indoor spaces or cluttered outdoor areas.
• the arms are configured to provide flexion in the axis passing through the center of the shroud and center of the opening in the arm, which is the main axis of flexion, i.e. the rotation is provided on at least one axis perpendicular to the axis of flexion, in particular the rotation is arranged by means of joints provided on the arm.
• the arms can be flexed in at least on more axis to allow deflection from the main axis.
• the opening of the arm can be rotated in the direction of the main axis of flexion in the extent corresponding to - 45 degrees to + 45 degrees, as can be shown on Fig. 2 and Fig. 3.
• the axis of rotation is passing through the hinges provided on the arm.
• This flexion is particularly desirable in the situation where collision with the obstacle shall be rapidly resolved by reaching appropriate angular momentum exerted on UAV by vectoring thrust.
• the arm that took the hit is diverted to the opposite direction, thereby pushing the UAV away from the wall, as shown on the Fig. 5a and Fig 5b.
• the principle of this behavior is also shown on Fig. 4a.
• the movement of the flexible arms can be achieved by electronical and/or mechanical means, which are responsible for balancing the position of the arms and result in thrust vectoring.
• the movement of the arms is controlled in one particular embodiment by the combination of servo motors, pulleys, strings and flexible elements, wherein the strings are connected with pulleys winding string with servo motors, and wherein the flexible elements keep tension on strings and return the arms to neutral position.
• Each arm is controlled via pulley by at least one servo motor using at least one string and at least one flexible element.
• the movement can be cable driven via Bovden mechanism.
• the servomotors are located under the shroud and actuate the arms through a pulley system.
• the pulleys are connected to the arms through a Bovden cable, which is run through a tube in the main body of the UAV. This mechanism allows for the transfer of torque from the servomotor to the arm, enabling the UAV to adjust the thrust vector.
• the Bovden cable is tensioned by the tensioning rubber mechanism to ensure consistent arm behavior and to compensate for cable slack.
• This combination of the cable drive Bovden mechanism and the tensioning rubber provides a robust and reliable system for controlling the flexible arms, ensuring accurate and responsive flight control.
• the use of the Bovden mechanism and tensioning rubber also enhances the compliance of the arms.
• the lightweight body of the UAV is preferably made from durable materials, such as carbon tubes or struts and/or plastic structures, to reduce weight and prolong the flight time.
• durable materials such as carbon tubes or struts and/or plastic structures.
• Providing a rigid and lightweight body structure is also beneficial with regards to the overall durability and aerodynamic efficiency.
• the flexible arms are made from a flexible latex sleeve that is attached to a plastic skeleton.
• This design allows the arms to be actuated by cable-driven, pneumatic, or hydraulic mechanisms, providing versatility and flexibility in terms of control. Having at least three flexible arms is necessary for control in all axes, while having four arms provides redundancy.
• present invention may be employed with more than four arms, provided that the air flow through the arms and the inner diameter of the arms is balanced with respect to the thrust achievable by the propellers and the overall weight of the arms does not lead to unfavorable restrictions to the design and function.
• the arms are arranged in a fourfold central symmetry, which promotes balance and stability.
• the diameter of the main body tube is proportional to the diameter of the arms, with the area of each arm being one quarter of the main body cross-sectional area.
• each arm is configured to receive a relative portion of the air passing through the shroud that is equal to the ratio between the shroud to the number of arms.
• the height of the main body comprising the shroud shall be kept as short as possible, while still accommodating both motors and propellers, to minimize drag. It is particularly desirable that the overall height of the shroud is less than the height the arm,
• the UAV according to this invention is advantageously provided with a range of sensors, such as a laser rangefinder for maintaining altitude or cameras and lidars for localization, mapping and planning.
• a range of sensors such as a laser rangefinder for maintaining altitude or cameras and lidars for localization, mapping and planning.
• the UAV according to this invention is also advantageously powered by a Li-pol battery.
• This energy source shall provide the power needed to operate the coaxial motors such as, for example, two brushless DC (BLDC) motors, a plurality of servomotors for controlling flexion of the flexible arms, and other onboard systems such as the flight controller with IMU and any additional sensors.
• BLDC brushless DC
• servomotors for controlling flexion of the flexible arms
• other onboard systems such as the flight controller with IMU and any additional sensors.
• the weight distribution is designed to keep the heavy components near the center of the UAV. This centralization of mass is crucial for the stability and control of the UAV, as it minimizes the moments of inertia and enhances its maneuverability. By keeping the heavy components near the center of the UAV, the weight distribution also minimizes the potential for unwanted movements and vibrations, resulting in smoother and more accurate flight. Therefore, in a preferred embodiment, the servo motors are placed within the area not exceeding half of the length of the propellers measured from the central axis of the UAV.
• Figure 1 is a perspective view of the UAV according to this invention having four flexible arms;
• Figure 2 is a side view of the UAV according to this invention having four flexible arms showing central axis of the UAV and the arms;
• Figure 3 is a top view of the UAV according to this invention having four flexible arms showing main axis of the flexion of the arms and basic direction of rotation thereof;
• Figure 4a is a cross-section view of the UAV according to this invention showing direction of air-flow and thrust vectoring of the arms with subsequent direction of movement of the UAV;
• Figure 4b is a cross-section view of the UAV showing balancing elements that are responsible for the movement of the arms;
• Figure 5a is a cross-section view of the UAV according to this invention simulating collision with the solid wall and subsequent flexion of the arm after impact with appropriate thrust vectoring.
• Figure 5b is a cross-section view of the UAV simulating collision with solid wall and showing air-flow and the direction of movement of the balancing elements responsible for thrust vectoring and subsequent movement of the UAV.
• the UAV comprises two coaxial counter-rotating motors 12 and with a pair of propellers 11 placed above each other that are individually controlled, wherein the propellers 11 are housed in shroud 1 having cylindrical inner opening 13. Below the shroud 1. are provided four flexible arms 2 for thrust vectoring, which provide the ability to redirect the thrust from the motors 12 for control and stability. Each arm 2 is actuated by a high-torque servomotor 32 Robotis AX-12a, allowing precise and responsive control. Powering the UAV are two Tarot 4114/320KV brushless DC (BLDC) motors 12, each paired with a 16-inch diameter, 6-inch pitch carbon propeller 11.
• BLDC brushless DC
• the soft arm 2 skeleton is 3D printed from polyiactic acid (PLA) material, providing a lightweight and rigid structure.
• PPA polyiactic acid
• the inside of each arm 2 is iined with a thin flexible latex cover 22 to reduce airflow friction and improve the compliance of the arms 2.
• the opening of the arm 2 can be rotated in the direction the main axis A in the extent corresponding to - 45 degrees to + 45 degrees.
• the UAV utilizes a cable drive Bovden mechanism to control the flexible arms 2.
• the servomotors 32 are located under the shroud 1 and actuate the arms 2 through a pulley system.
• the pulleys 31 are connected to the arms 2 through a Bovden cable representing the string 34, which is run through a tube in the main body of the UAV. This mechanism allows for the transfer of torque from the servomotor 32 to the arm 2, enabling the UAV to adjust the thrust vector.
• the Bovden cable is tensioned by the tensioning rubber mechanism representing the flexible balancing element 33 to ensure consistent arm behavior and to compensate forcable slack.
• This combination of the cable drive Bovden mechanism and the tensioning rubber provides a robust and reliable system for controlling the flexible arms 2, ensuring accurate and responsive flight control.
• the use of the Bovden mechanism and tensioning rubber also enhances the compliance of the arms 2.
• the shroud 1 of the UAV is made from carbon struts, providing a rigid and lightweight skeleton, and features plastic latex walls for added durability and aerodynamic efficiency.
• the arms 2 are arranged in a fourfold central symmetry, which promotes balance and stability.
• the diameter of the shroud 1 is proportional to the diameter of the arms 2, with the area of each arm 2 being one quarter of the shroud 1 cross-sectional area.
• the height of the shroud 1. is kept as short as possible to minimize drag, while still accommodating both motors 12 and propellers 11.
• the diameter of the shroud 1 is slightly larger than the diameter of the propellers 11 to maximize the ducted fan effect, which enhances the overall aerodynamic efficiency of the UAV.
• the UAV is powered by a Li-pol battery. This energy source provides the power needed to operate the two brushless DC (BLDC) motors 12, four servomotors 32, and other onboard systems such as the flight controller with IMU and additional sensors.
• BLDC brushless DC
• the weight distribution is designed to keep the heavy components near the center of the UAV. This centralization of mass is crucial for the stability and control of the UAV, as it minimizes the moments of inertia and enhances its maneuverability. By keeping the heavy components near the center of the UAV, the weight distribution also minimizes the potential for unwanted movements and vibrations, resulting in smoother and more accurate flight.
• Present invention is an UAV which is utilizable, for example, in the environments where collisions with other objects shall be avoided.
• the extent of possible utilization is thereby not limited.

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• Engineering & Computer Science (AREA)
• Aviation & Aerospace Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Professional, Industrial, Or Sporting Protective Garments (AREA)
• Toys (AREA)

Priority Applications (2)

Applications Claiming Priority (1)

Publications (1)

Family

ID=86330316

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (3)

• 2023
  • 2023-04-20 WO PCT/CZ2023/000017 patent/WO2024217605A1/en active Application Filing
  • 2023-04-20 CZ CZ2025-89A patent/CZ202589A3/cs unknown

Patent Citations (3)

Non-Patent Citations (3)

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