A tilt-rotor multi-rotor unmanned aerial vehicle with omni-directionality and working method

Abstract

This application belongs to the field of multi-rotor unmanned aerial vehicle (UAV) technology, specifically relating to an omnidirectional tilting rotor multi-rotor UAV and its operating method. The UAV includes a fuselage and a drive assembly connecting to the arm. The drive assembly, located at the end of the arm, includes a rotor and a rotor blade. At least one rotor is tilted and fixed at a preset fixed angle, such that the rotor blade disk plane forms a non-zero angle with the fuselage reference plane. The rotors are arranged in pairs along the diagonal, with each pair having an equal absolute value of the tilt angle and opposite directions. The rotor blade surfaces are distributed in at least two non-coplanar planes in three-dimensional space. Through the tilting rotor design and the diagonally paired opposite tilt angle configuration, the omnidirectional flight capability of the UAV is improved, enhancing flight stability and maneuverability. This solves the technical problems of insufficient omnidirectionality and limited flight attitude in traditional multi-rotor UAVs, making it suitable for complex environment operations and high-precision flight missions.

Description

Technical Field

[0001] This application belongs to the field of multi-rotor unmanned aerial vehicle (UAV) technology, specifically relating to an omnidirectional tilting rotor multi-rotor UAV and its operating method. Background Technology

[0002] Multirotor drones have been widely used in aerial photography, inspection, and search and rescue due to their advantages such as simple structure, vertical takeoff and landing, and good hovering performance. However, traditional multirotor drones generally adopt a layout in which all rotors are coplanar and the thrust direction is fixed. Their translational motion must be achieved by the horizontal component force generated by the tilting of the fuselage, resulting in strong coupling between motion and attitude.

[0003] In the prior art, for example, Chinese patent application CN106516095A discloses a conventional hexacopter UAV, in which all six rotors are mounted in the same plane, with the rotor axes perpendicular to the fuselage plane. When this type of UAV maneuvers horizontally, it needs to first change its pitch or roll angle to generate a horizontal component in the total lift vector, thereby driving the UAV to move. Although this control method is simple in structure and technologically mature, it has significant drawbacks: firstly, horizontal translation must be accompanied by attitude changes, making it impossible to achieve pure horizontal movement without changing the nose direction; secondly, there is a response delay, as the process from command to generation of horizontal acceleration requires attitude adjustment, limiting agility in dynamic environments; and thirdly, it cannot independently generate thrust in any horizontal direction, lacking omnidirectional mobility. Summary of the Invention

[0004] The purpose of this application is to provide an omnidirectional tilting rotor multi-rotor UAV and its operating method to solve the technical problems of insufficient omnidirectionality and limited flight attitude of traditional multi-rotor UAVs.

[0005] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, the present invention provides an omnidirectional tilting rotor multi-rotor unmanned aerial vehicle (UAV), comprising a fuselage and a plurality of arms connected to the fuselage, the UAV further comprising: A drive assembly with the same number of arms, the drive assembly being correspondingly disposed at the end of the arm, including a rotor and a rotor blade mounted at the output end of the rotor; At least one of the rotors is fixedly mounted on the corresponding arm at a preset fixed tilt angle, such that the disk plane of the corresponding driven rotor forms a non-zero angle with the reference plane of the fuselage. The rotors are arranged in pairs along the diagonal direction, with the two rotors in each pair having equal absolute tilt angles and opposite directions, so that the rotor blades are distributed in at least two non-coplanar planes in three-dimensional space.

[0006] As a further improvement of the present invention, the fixed tilt angle ranges from 0 degrees to 90 degrees.

[0007] As a further improvement of the present invention, the absolute value of the fixed tilt angle of all rotors is the same.

[0008] As a further improvement of the present invention, the fuselage is made of carbon fiber material, and the arm is a carbon fiber tube.

[0009] As a further improvement of the present invention, the number of drive components is not less than six, and the rotors of all drive components are inclined at the fixed tilt angle; the drive components are arranged in a centrally symmetrical or rotationally symmetrical manner about the fuselage. The plurality of arms are arranged coplanarly and evenly distributed around the fuselage; the plurality of drive components are divided into multiple pairs, each pair containing two drive components arranged diagonally about the center of the fuselage; the tilting directions of the rotors in the same pair of drive components are opposite.

[0010] As a further improvement of the present invention, the control allocation matrix of the relationship between the thrust direction and spatial position of the driving component is a full-rank matrix.

[0011] As a further improvement of the invention, in each pair of drive components, the two rotors are tilted in opposite directions, such that the disk planes of at least two rotors are located in two different planes.

[0012] As a further improvement of the present invention, the rotors of two adjacent drive components rotate in opposite directions and are configured with positive or negative rotors corresponding to the rotation directions.

[0013] Secondly, the present invention provides a method for operating an omnidirectional tilting rotor multirotor unmanned aerial vehicle (UAV), applied to the aforementioned omnidirectional tilting rotor multirotor UAV, comprising: Based on the force and moment equations of a multi-rotor UAV, the omnidirectional condition that makes the control assignment matrix of the UAV full rank is derived and determined. Based on the omnidirectional condition, an inclined rotor configuration is designed, and the rotors in all inclined rotor configurations are installed with the arm rotated at a fixed angle relative to the same axis of rotation. Based on the designed tilted rotor configuration, its dynamic model is established, and the corresponding system matrix is ​​calculated. Verify whether the calculated system matrix satisfies the full rank condition. If so, confirm that the tilted rotor configuration enables the UAV to have omnidirectionality.

[0014] Compared with the prior art, this application has the following beneficial effects: This application provides an omnidirectional tilting rotor multi-rotor unmanned aerial vehicle (UAV). By tilting and fixing at least one rotor to the end of the arm at a preset fixed tilt angle, the corresponding rotor disk plane forms a non-zero angle with the fuselage reference plane. This overcomes the limitation of insufficient omnidirectionality caused by the parallelism between the rotor plane and the fuselage plane in traditional multi-rotor UAVs, and solves the technical problem of limited flight attitude. At the same time, it adopts a rotor configuration of two pairs of rotors in the diagonal direction. The absolute value of the tilt angle of each pair of rotors is equal and the direction is opposite, so that the rotor blades are distributed in at least two non-coplanar planes in three-dimensional space. This reverse tilt angle design can generate torque components in opposite directions during flight. Through torque balance, flight stability is enhanced. Compared with the single tilt angle design, it has better anti-interference ability and maneuverability, and synergistically achieves the technical effect of improving omnidirectional flight capability and enhancing adaptability to complex environments. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the connection structure between the arm and the rotor of the present invention; Figure 3 This is a top view of the structure of the present invention.

[0017] In the picture: 1. Fuselage; 2. Arm; 3. Rotor. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] Example 1 Traditional multi-rotor drones typically employ conventional configurations such as quadcopters, hexacopterers, and octocopters. Their rotors are all positioned perpendicular to the fuselage's reference plane, generating only a single thrust component along the vertical direction of the fuselage. While these drones possess six degrees of freedom, the number of independently controllable variables is less than the number of degrees of freedom, classifying them as underactuated systems. In actual flight, when a drone performs translational maneuvers such as forward or side-flying, it must be accompanied by rotational maneuvers such as pitch and roll. This high coupling between translation and motion significantly reduces maneuverability in confined spaces, making it difficult to meet the high-precision, high-flexibility flight requirements of complex scenarios such as underground pipeline inspection, high-voltage line inspection, and confined space operations.

[0020] Therefore, this embodiment provides an omnidirectional tilting rotor multi-rotor unmanned aerial vehicle (UAV), including a fuselage, arms, and rotors. The fuselage is the main load-bearing component of the UAV, and its internal components include a flight control system, a power system, and electrical equipment. The arms are connected to the outer surface of the fuselage, with one end fixedly connected to the fuselage and the other end equipped with a drive assembly. The drive assembly includes a rotor and rotors; the rotor is fixedly mounted at the end of the arms, and the rotors are mounted at the output end of the rotor.

[0021] Please see Figure 1 The overall structural diagram of this invention shows the basic configuration of the drone. The drone includes a fuselage 1, multiple arms 2, and rotors 3 mounted at the ends of the arms. Multiple arms 2 are evenly distributed on the outer surface of the fuselage 1, the number of arms 2 being the same as the number of drive components. Inside the fuselage 1 is a Pixhawk flight controller, multiple electronic speed controllers, a lithium battery, multiple brushless DC motors, and an odometer. The installation positions of these electrical devices are rationally arranged to ensure the drone's center of gravity balance and stability during flight.

[0022] exist Figure 1 The diagram defines an inertial frame FI and a body frame FB, with the XYZ axes of each coordinate system marked. The inertial frame FI is a reference coordinate system fixed to the ground coordinate system, while the body frame FB is a coordinate system fixed to the UAV's fuselage. The origin of the body frame FB is located at the geometric center of the fuselage, with the XB axis pointing towards the nose, the YB axis pointing towards the right side of the fuselage, and the ZB axis perpendicular to the fuselage plane and pointing upwards.

[0023] The fuselage 1 and the arm 2 are fixedly connected. In this embodiment, the arm 2 is fixedly connected to the outer surface of the fuselage 1 by multiple bolts. The connecting end of the arm 2 is designed with a connecting surface that matches the curvature of the outer surface of the fuselage 1, ensuring that the arm 2 fits tightly against the outer surface of the fuselage 1 after installation. A reinforcing structure is also provided at the connection point to enhance the connection strength and prevent the arm 2 from loosening due to vibration or stress during flight.

[0024] In another preferred embodiment, the arm 2 and the fuselage 1 can also be manufactured as a single piece, meaning the fuselage 1 and arm 2 are processed from the same piece of carbon fiber composite material to form an integral structure. This single-piece structure eliminates the connection interface between the arm and the fuselage, further improving the overall structural rigidity and strength while reducing weight. The fuselage is made of carbon fiber, which is lightweight, has high structural strength, and strong resistance to deformation, meeting the lightweight and high stability requirements of UAVs. The arms are made of carbon fiber tubing, and all arms are of uniform specifications to ensure uniform stress on the entire aircraft. All arms are in the same plane, evenly arranged around the center of the fuselage, and the angle between adjacent arms is consistent. In this embodiment, six arms are preferred, with an angle of sixty degrees between adjacent arms.

[0025] The end of arm 2 is detachably and fixedly connected to the rotor. The rotor is fixedly installed to the end of arm 2 via a special connector. One end of the connector is bolted to the end of arm 2, and the other end is fixedly connected to the rotor's housing. In this embodiment, the relative positional relationship between the rotor and arm 2 is fixed; that is, the rotor is fixedly installed after rotating relative to arm 2 around the same axis of rotation by a preset fixed tilt angle. The size of this fixed tilt angle is determined by the design and cannot be adjusted after the UAV leaves the factory.

[0026] The specific method for tilting the rotor is as follows: A mounting base is provided at the end of the machine arm 2, and the mounting base has mounting holes and positioning slots. The rotor's outer shell has mounting protrusions corresponding to the mounting holes and positioning blocks corresponding to the positioning slots. During installation, the mounting protrusions of the rotor are inserted into the mounting holes of the mounting base, and the positioning blocks are simultaneously engaged in the positioning slots. Then, the rotor is fixedly connected to the mounting base with bolts. The mounting base is pre-set with an tilt angle relative to the end of the machine arm 2, and this tilt angle is the fixed tilt angle of the rotor.

[0027] The rotor's output end is axially fixed to rotor 3. The rotor's output shaft is a hollow shaft structure, and the center hole of rotor 3 is fitted onto the output shaft. Rotor 3 is fixed to the output shaft with a self-locking nut, ensuring that rotor 3 rotates synchronously with the rotor's output shaft. During installation, attention must be paid to the directionality of rotor 3; the positive and negative rotors are installed in opposite directions.

[0028] The drive assembly includes a rotor and a rotor blade. The rotor is fixedly mounted at the end of the arm, and the rotor blade is coaxially mounted at the output end of the rotor. The rotor drives the rotor blade to rotate, generating flight thrust. In this embodiment, there are six drive assemblies, which meets the requirement of having at least six. All drive assemblies are arranged symmetrically around the fuselage to ensure force balance during flight.

[0029] Multiple robotic arms 2 are evenly arranged around the outer surface of the fuselage 1. In this embodiment, six robotic arms 2 are used, symmetrically arranged on the outer side of the fuselage 1. The six robotic arms 2 are in the same plane, with an included angle of 60 degrees between adjacent robotic arms 2. The six robotic arms 2 are divided into three pairs, with each pair of robotic arms 2 arranged diagonally about the center of the fuselage 1. For example, when six evenly distributed installation positions are provided on the outer side of the fuselage 1, the first pair of robotic arms 2 is installed at two positions 180 degrees apart, the third pair of robotic arms 2 is installed at two positions 60 degrees apart from the first pair of robotic arms 2, and the fifth pair of robotic arms 2 is installed at the remaining two positions.

[0030] Six rotors are fixedly mounted at the ends of six arms 2. The rotors are divided into three pairs, diagonally opposite each other on the fuselage 1. Each rotor has the same absolute value of its tilt angle within its own rotor system, and the tilt directions of rotors within the same pair are opposite. For details, please refer to... Figure 2 Let the i-th rotor system Fri be established with the geometric center of the rotor as the origin. The three orthogonal axes XYZ of this coordinate system are marked in the figure. The angle between the Z-axis Fri,z direction of the rotor system Fri and the Z-axis FB,Z direction of the machine system FB is defined as θ. This angle is the fixed angle through which the i-th rotor rotates around its arm.

[0031] The first pair of rotors are tilted in opposite directions, with one rotor tilting towards the front of the machine and the other towards the rear, but the absolute values ​​of their tilt angles are equal. The second pair of rotors are tilted in opposite directions, with one rotor tilting towards the left side of the machine and the other towards the right side. The third pair of rotors are tilted in opposite directions, also arranged diagonally.

[0032] This tilting rotor configuration distributes the blades of the six rotors across multiple non-coplanar planes. The plane containing the rotor blades has a non-zero angle with the fuselage's reference plane, allowing the thrust generated by the rotors to be decomposed not only vertically upwards but also horizontally, providing the UAV with omnidirectional mobility.

[0033] The rotor blades of each rotor are arranged in an alternating direction of rotation, with adjacent rotors rotating in opposite directions. Rotors designed for counter-clockwise rotation use positive rotors, while those designed for clockwise rotation use negative rotors. Taking six rotors as an example, adjacent rotors along the fuselage rotate alternately in counter-clockwise and clockwise directions. This alternating arrangement of positive and negative rotors effectively overcomes the influence of gyroscopic torque on the flight stability of the UAV.

[0034] The core improvement of this application lies in the tilted fixed installation method of the rotor. At least one rotor is tilted and fixed to the corresponding arm at a preset fixed tilt angle, so that the plane of the rotor disk driven by the rotor forms a non-zero angle with the fuselage reference plane. In this embodiment, all rotors are tilted at the same fixed tilt angle with the same absolute value. The fixed tilt angle ranges from zero to ninety degrees, preferably forty-five degrees, and can be adjusted according to actual flight requirements.

[0035] The rotors are arranged in pairs along the diagonal direction. In this embodiment, the six rotors are divided into three pairs, with each pair arranged diagonally about the center of the fuselage. Within the same pair of rotors, the absolute values ​​of the tilt angles of the two rotors are equal, and their tilt directions are opposite, so that the blade surfaces of each rotor are distributed in at least two non-coplanar planes in three-dimensional space. In this embodiment, the blade surfaces of the six rotors are distributed in three non-coplanar planes, realizing the decomposition and synthesis of multi-directional thrust components in three-dimensional space.

[0036] The rotor and the arm are fixedly connected, which can be achieved by bolting, snap-fitting or integral molding. The rotor is fixed after rotating around the arm axis at a preset angle. There is no relative movement in the tilt state, which ensures the stability of the tilt angle and the precision of thrust output during flight.

[0037] All rotors use propellers of the same model and size to ensure consistent thrust output. The rotors of adjacent drive components rotate in opposite directions, and are matched with either a positive or negative propeller configuration according to the direction of rotation: counterclockwise rotors use positive propellers, and clockwise rotors use negative propellers. The alternating arrangement of positive and negative propellers effectively counteracts the gyroscopic torque and counter-torque generated by rotor rotation, improving flight stability.

[0038] The fuselage houses a flight control module, electronic speed controllers, a lithium battery, brushless DC motors, and an odometer. The flight control module uses the Pixhawk flight controller as the core of the entire system, receiving sensor signals and outputting control commands. The number of electronic speed controllers matches the number of drive components, each controlling the speed of one rotor. The lithium battery provides power to the electrical components. The brushless DC motors serve as the power source for the rotors, outputting stable torque. The odometer is used to sense the drone's position and motion status, enabling precise positioning and attitude control. Specifically, the electronic speed controllers and brushless DC motors are connected via a three-phase power line. The control signal input of the electronic speed controllers is connected to the output of the Pixhawk flight controller. The Pixhawk flight controller receives control commands from the remote controller or the autonomous navigation algorithm, controlling the output frequency of each electronic speed controller, thereby controlling the speed of each brushless DC motor and achieving independent control of the thrust of each rotor. The lithium battery provides power to the entire flight control and power systems, while the odometer measures the drone's flight speed and position, providing status feedback to the flight control system.

[0039] In this embodiment, the control allocation matrix constructed from the thrust direction and spatial position relationship of the UAV drive component is a full-rank matrix. Based on the force and moment equations of a multi-rotor UAV, it is derived that the core condition for the UAV to possess omnidirectionality is that the control matrix is ​​full-rank and the number of independent control variables equals the number of degrees of freedom of the UAV.

[0040] Substituting the rotor's position and orientation matrices into the control allocation matrix for calculation, it can be determined that the matrix is ​​in a full-rank state, indicating that the six independent control variables of the UAV of this invention are independent of each other, the system is a fully driven system, gets rid of the traditional underactuated characteristics, and achieves decoupling of translation and rotation.

[0041] The operating method of an omnidirectional tilting rotor multi-rotor UAV specifically includes the following steps: Based on the force and moment equations of multi-rotor UAVs, the omnidirectional condition for achieving full rank in the UAV control matrix is ​​derived and determined, clarifying that the number of independent control variables must match the number of degrees of freedom.

[0042] Based on the above omnidirectional conditions, an inclined rotor configuration is designed. All rotors are installed with a fixed tilt angle relative to the arm, rotating around the same axis of rotation, to ensure uniform tilt angles and paired opposite tilts.

[0043] Based on the designed tilted rotor configuration, a UAV dynamics model is established, and the rotor position and orientation parameters are substituted to calculate the corresponding system control matrix.

[0044] Verify whether the calculated system matrix satisfies the full rank condition. If it does, then confirm that the tilted rotor configuration enables the UAV to have omnidirectional flight capability.

[0045] This invention achieves multi-directional thrust component output in three-dimensional space by tilting and fixing the rotors, making the rotor disk plane form a non-zero angle with the fuselage reference plane, and combining this with a paired, counter-tilting arrangement. All rotors have the same absolute tilt angle, the arms are evenly arranged in a coplanar manner, and the rotors are configured with alternating forward and reverse directions. Combined with a full-rank control matrix design, this makes the UAV a fully driven system, completely overcoming the shortcomings of traditional multi-rotor UAVs such as underactuation and coupling of translation and rotation. It possesses omnidirectional flight capability and can achieve uncoordinated translation and independent rotation in confined spaces, significantly improving flight flexibility and control precision, making it suitable for various complex operational scenarios.

[0046] Example 2 Please see Figure 1-3The present invention provides a technical solution: an omnidirectional tilting rotor multi-rotor drone, including a fuselage 1, arms 2 and rotors 3. A Pixhawk flight controller, multiple electronic speed controllers, a lithium battery, multiple brushless DC motors and an odometer are evenly distributed inside the fuselage 1. Multiple arms 2 are evenly arranged on the outer surface of the fuselage 1. A rotor is installed at one end of the arm 2 and the rotor output end is connected to the rotor 3.

[0047] For the configuration of rotor 3, the drone fuselage 1 is first considered as a rigid body. The following are the force and moment equations in drone dynamics:

[0048]

[0049] In the formula It is the total force acting on the drone. It is the torque acting on the drone. It is the first drone The thrust generated by the rotation of the rotor blades It is the first drone The direction vector of each rotor, It is the first drone The position vectors of the rotors. The force and torque equations can be integrated into the following equations:

[0050] In the formula It is the direction matrix of the UAV rotor. It is the position matrix of the UAV rotor. It is the resultant force of the thrust generated by the rotation of all rotor blades 3. To simplify the expression, a matrix is ​​introduced. , The expression is as follows:

[0051] Because of the matrix The rank of the variable determines the number of independent control variables of the UAV. Whether it is full rank determines whether the thrust generated by each rotor's rotation can independently affect the forces and torques acting on the UAV. The UAV's motion has six degrees of freedom, so the number of its independent control variables needs to be greater than or equal to 6 in order for the UAV to form an overdrive or fully drive system.

[0052] For traditional multi-rotor UAVs, the rotor blades of the rotor are all located in the same plane in three-dimensional space, resulting in a matrix... The rotor structure is not full rank, ensuring that the number of independent control variables is always less than its number of degrees of freedom (6). Therefore, when designing an omnidirectional UAV, the number of independent control variables can be increased by adjusting its rotor structure, thereby creating overdrive or full-drive characteristics and giving it omnidirectionality.

[0053] This embodiment employs a tilting rotor structure with six rotors 3, each rotor rotating around its arm 2 at a fixed angle. Its overall appearance is shown in the diagram. Figure 1 As shown in the figure. An inertial frame is defined in the figure. Machine system Each coordinate system - - The three orthogonal axes are shown in the figure, and the direction vectors of each rotor are also marked in the figure. The improvement over traditional multi-rotor UAVs lies in the fact that the rotor blades of each rotor lie in multiple planes in three-dimensional space. As shown in the diagram. Figure 2 As shown, the first [element] is established with the rotor's geometric center as the origin. One rotor system The coordinate system - - The three orthogonal axes are as shown in the figure. The rotor system... of axis Direction and machine system of axis The angle between directions is defined as The included angle is the first... The fixed angle through which each rotor rotates around its arm.

[0054] The drone's six rotors are divided into three pairs, diagonally opposite to the fuselage. Each rotor has the same absolute tilt angle within its own rotor system, and rotors within the same pair tilt in opposite directions. The specific tilt angle is determined by actual requirements and should be located at... The range is between. This tilting rotor design places the rotor blades 3 of the six rotors in three planes in three-dimensional space. Since this UAV is an improvement on a traditional hexacopter UAV, all six of its arms 2 are located in the same plane, and the positional relationship between adjacent arms 2 is shown in the diagram. Figure 3 As shown, the included angle is 60°. The rotation directions of the rotor blades 3 of each rotor are staggered, and the rotation directions of adjacent rotor blades 3 are opposite.

[0055] Based on the above description of the structural design, the rotor position matrix can be obtained. and direction matrix They are respectively:

[0056]

[0057] Position matrix In This is the distance between the rotor's center of mass and the machine body's center of mass.

[0058] The designed omnidirectional UAV is analyzed based on the force and moment equations of the UAV. The UAV has six rotor-driven rotors, therefore it has at least six control variables; the position matrix of the rotors... and direction matrix Substitute into the matrix As can be seen from the matrix, it is a full-rank matrix, therefore the six control variables of the UAV are independent of each other. The number of independent control variables of the UAV system is equal to the number of its degrees of freedom, therefore it is a fully driven system, and thus the designed UAV structure has omnidirectional properties.

[0059] This omnidirectional drone uses carbon fiber as the main body (1) and six identical carbon tubes as its six arms (2), ensuring the drone's overall lightweight yet robust characteristics. The six rotors (3) should also be made of the same model and size, but the rotors should be arranged in an alternating pattern of forward and reverse propellers. Rotors designed for counter-clockwise rotation use forward propellers, and those designed for clockwise rotation use reverse propellers to overcome gyroscopic torque.

[0060] This invention improves upon traditional hexacopter drones by rotating each rotor around arm 2 at a fixed angle and incorporating onboard electrical equipment for sensing and flight. The use of a tilted rotor multi-rotor drone structure with a fixed rotor tilt angle enables the designed drone to be an all-drive system, thus achieving omnidirectional capability and overcoming the underactuated characteristics of traditional multi-rotor drones. The design steps are as follows: First, the conditions for achieving omnidirectional capability of the multi-rotor drone are analyzed based on the force and torque equations of the drone. Then, the specific structural form of the tilted rotor omnidirectional drone with a fixed rotor tilt angle is designed, and its omnidirectional capability is analyzed based on its dynamic model. Finally, the omnidirectional capability of the drone structure is verified.

[0061] The key improvement of this invention over existing technologies lies in its tilted rotor configuration. Unlike traditional multi-rotor UAVs where each rotor is vertically upward, the rotor of this invention is installed at a fixed tilt angle. This fixed tilt angle creates a non-zero angle between the rotor blades and the reference plane of the fuselage, thereby altering the spatial distribution of the thrust vector.

[0062] In this embodiment, the fixed tilt angle θ ranges from 0 degrees to 90 degrees. Too small a tilt angle results in insufficient horizontal thrust, leading to poor omnidirectional performance; too large a tilt angle results in insufficient vertical upward thrust, affecting hovering performance. Through theoretical analysis and experimental verification, it has been found that when the fixed tilt angle θ is set between 30 and 60 degrees, the UAV can simultaneously possess good hovering performance and omnidirectional mobility.

[0063] The fixed tilt angles of each rotor are set in diagonal pairs, with each pair of rotors having the same absolute tilt angle and opposite directions. This arrangement ensures that when the system generates yaw moment, it does not affect forces and moments in other directions, facilitating independent control. Furthermore, the opposite tilt directions of the same pair of rotors allow the system to maintain good center of gravity balance during large tilt angle maneuvers.

[0064] Another key improvement of this invention is that the rotor blades are located in at least two non-coplanar planes in three-dimensional space. In traditional UAVs, the rotor blades are all located in the same plane, resulting in a linear correlation between the projections of the thrust direction vectors in space. This invention, through a tilted rotor configuration, distributes the rotor blades in multiple non-coplanar planes, breaking the linear correlation constraint between thrust direction vectors. In this embodiment, the blades of the six rotors are located in three planes in three-dimensional space. These three planes are not parallel and do not completely coincide, making the distribution of the six thrust direction vectors in space more dispersed, thus eliminating the linear correlation between them.

[0065] This invention achieves full rank in the control allocation matrix through the aforementioned structural design. Full rank in the control allocation matrix means that the six independent control variables can completely cover the six degrees of freedom of the UAV, achieving full-drive control. To ensure full rank in the control allocation matrix, this invention optimizes the number, position, and tilt angle of the rotors. The number of rotors is no less than six, preferably a multiple of six or a number sufficient to enable the system to achieve full-drive or overdrive states. The rotors are arranged with central or rotational symmetry along the fuselage to ensure good symmetry in the spatial distribution of each rotor.

[0066] Example 3 In another embodiment, the drone employs eight drive components. The eight arms are evenly arranged around the fuselage, with an angle of 45 degrees between adjacent arms. The eight rotors are also divided into four pairs diagonally, with each pair having an equal absolute tilt angle and opposite directions.

[0067] The eight rotor blades are positioned in four planes in three-dimensional space, further enhancing the spatial distribution of the thrust direction vector. With eight control variables, the system enters an overdriven state, where the number of independent control variables exceeds the number of degrees of freedom. The flight control system can improve its reliability and anti-interference capability through redundant control.

[0068] Example 4 In another embodiment, the drone employs twelve drive components. The twelve arms are evenly arranged around the fuselage, with an angle of 30 degrees between adjacent arms. The twelve rotors are divided into six pairs, also arranged according to the principle of diagonal pairs, equal absolute tilt angles, and opposite directions.

[0069] The twelve-rotor configuration has more redundant control capabilities. When some rotors fail, the system can still maintain basic flight capabilities, improving the survivability of the UAV in complex environments.

[0070] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0071] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0072] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0073] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0074] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative descriptions used herein will be interpreted accordingly.

[0075] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A tilting rotor multi-rotor unmanned aerial vehicle with omnidirectional rotation, characterized in that, The drone includes a fuselage and several arms connected to the fuselage, and further includes: A drive assembly with the same number of arms, the drive assembly being correspondingly disposed at the end of the arm, including a rotor and a rotor blade mounted at the output end of the rotor; At least one of the rotors is fixedly mounted on the corresponding arm at a preset fixed tilt angle, such that the disk plane of the corresponding driven rotor forms a non-zero angle with the reference plane of the fuselage. The rotors are arranged in pairs along the diagonal direction, with the two rotors in each pair having equal absolute tilt angles and opposite directions, so that the rotor blades are distributed in at least two non-coplanar planes in three-dimensional space.

2. The omnidirectional tilting rotor multi-rotor UAV according to claim 1, characterized in that, The fixed tilt angle ranges from 0 degrees to 90 degrees.

3. The omnidirectional tilting rotor multi-rotor UAV according to claim 2, characterized in that, The absolute value of the fixed tilt angle of all rotors is the same.

4. The omnidirectional tilting rotor multi-rotor UAV according to claim 1, characterized in that, The fuselage is made of carbon fiber material, and the arms are carbon fiber tubes.

5. The omnidirectional tilting rotor multi-rotor UAV according to claim 1, characterized in that, The number of drive components is not less than six, and the rotors of all drive components are inclined at the fixed tilt angle; a plurality of drive components are arranged in a centrally symmetrical or rotationally symmetrical manner about the fuselage.

6. The omnidirectional tilting rotor multi-rotor UAV according to claim 5, characterized in that, The plurality of robotic arms are coplanarly arranged and evenly distributed around the fuselage; the plurality of drive components are divided into multiple pairs, each pair containing two drive components arranged diagonally about the center of the fuselage; The rotors in the same pair of drive components tilt in opposite directions.

7. The omnidirectional tilting rotor multi-rotor UAV according to claim 6, characterized in that, The control allocation matrix for the relationship between the thrust direction and spatial position of the drive component is a full-rank matrix.

8. The omnidirectional tilting rotor multi-rotor UAV according to claim 7, characterized in that, In each pair of drive components, the two rotors are tilted in opposite directions, such that the disk planes of at least two rotors are located in two different planes.

9. The omnidirectional tilting rotor multi-rotor UAV according to claim 1, characterized in that, The rotors of two adjacent drive components rotate in opposite directions and are configured with positive or negative rotors corresponding to the rotation direction.

10. A method for operating an omnidirectional tilting rotor multirotor unmanned aerial vehicle (UAV), applied to the omnidirectional tilting rotor multirotor UAV as described in any one of claims 1 to 9, characterized in that, include: Based on the force and moment equations of a multi-rotor UAV, the omnidirectional condition that makes the control assignment matrix of the UAV full rank is derived and determined. Based on the omnidirectional condition, an inclined rotor configuration is designed, and the rotors in all inclined rotor configurations are installed with the arm rotated at a fixed angle relative to the same axis of rotation. Based on the designed tilted rotor configuration, its dynamic model is established, and the corresponding system matrix is ​​calculated. Verify whether the calculated system matrix satisfies the full rank condition. If so, confirm that the tilted rotor configuration enables the UAV to have omnidirectionality.

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