CN112319786B

CN112319786B - Multi-shaft coaxial double-propeller multi-rotor unmanned aerial vehicle

Info

Publication number: CN112319786B
Application number: CN202011266129.9A
Authority: CN
Inventors: 梁帅; 江翠红; 金宇韬; 李世清; 吴俊琦; 张执南
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2020-11-13
Filing date: 2020-11-13
Publication date: 2022-06-28
Anticipated expiration: 2040-11-13
Also published as: CN112319786A

Abstract

The invention provides a multi-shaft coaxial double-propeller multi-rotor unmanned aerial vehicle, which comprises: the aircraft comprises a machine frame cabin, a pluggable machine arm, an undercarriage, a propeller protection device, a power device and an electric control system. The eight pluggable machine arms are circumferentially arrayed on the horizontal plane of the cabin, and the tail end of each machine arm is connected with two coaxial brushless motors through a motor base with a mounting angle to drive the two propellers to rotate in opposite directions. The undercarriage is of a pair of steel structures, and the propeller protection device is a hollow cone arranged below the lower-layer motor. The technology of the invention can be applied to manned multi-rotor or heavy-load multi-rotor unmanned aerial vehicles, has the advantages of simple structure, low manufacturing cost, small size, easy transportation, heavy load, rollover prevention and strong redundancy, can normally fly when a plurality of motor propellers fail, and ensures the life safety of the multi-shaft coaxial double-propeller multi-rotor unmanned aerial vehicle and passengers.

Description

Multi-shaft coaxial double-propeller multi-rotor unmanned aerial vehicle

Technical Field

The invention relates to a manned unmanned aerial vehicle, in particular to a multi-shaft coaxial double-propeller multi-rotor unmanned aerial vehicle.

Background

In recent years, with the rapid development of motor technology, battery technology and new material technology, the multi-rotor unmanned aerial vehicle is continuously developed towards the directions of heavy load, long endurance, safety and intelligence, and the design and development of the heavy load multi-rotor unmanned aerial vehicle and even the manned multi-rotor unmanned aerial vehicle become possible. The manned multi-rotor unmanned aerial vehicle can be applied to scenes such as tourism, entertainment and sightseeing, emergency medical service, fire fighting, express logistics, power grid maintenance, pipeline inspection, pesticide spraying and the like; and military war scenes such as offshore personnel material transportation, maritime operation and the like.

At present, manned multi-rotor unmanned aerial vehicle and big many rotor unmanned aerial vehicle of load have the size huge, aerodynamic resistance is big, driftage manipulation performance subalternation problem, also lack the consideration to factors such as the many rotor unmanned aerial vehicle of manned and big many rotor unmanned aerial vehicle of load side wind descends and easily turns on one's side, the screw or motor easily crash after becoming invalid and probably threaten passenger life safety.

Disclosure of Invention

In view of the above, the invention designs a manned multi-shaft coaxial double-propeller multi-rotor unmanned aerial vehicle, which has the advantages of flexible control, simple structure and the like of multi-rotor unmanned aerial vehicles, and simultaneously adopts a coaxial double-propeller technology to reduce the overall size of the unmanned aerial vehicle so as to reduce aerodynamic resistance, improve load carrying capacity so as to meet manned demands, optimize the structure so as to ensure the efficiency and safety of the unmanned aerial vehicle, and avoid the problems of rollover of the manned multi-rotor unmanned aerial vehicle, crash of the unmanned aerial vehicle with failed motor propellers and the like. The specific scheme is as follows:

A multi-shaft coaxial double-propeller multi-rotor unmanned aerial vehicle comprises a rack cabin and a plurality of groups of rotor wing mechanisms symmetrically arranged on the left side and the right side of the rack cabin, wherein each rotor wing mechanism is connected with the rack cabin through a horn, each rotor wing mechanism comprises a motor mounting seat fixedly connected with the horn, each motor mounting seat is of a hollow structure, and one end of each motor mounting seat is provided with a sleeve connected with the horn;

the upper side and the lower side of the motor mounting seat are respectively provided with a driving motor, the steering directions of the upper driving motor and the lower driving motor are opposite, and an output shaft of the driving motor is provided with a propeller;

two driving motors of each rotor wing mechanism are obliquely and symmetrically arranged at the upper side and the lower side of the motor mounting seat in an up-and-down manner, the included angle between the output shaft of each driving motor and the vertical plane where the axis of the driving motor is connected with the aircraft arm is alpha, wherein,

in the two adjacent front and back rotor wing mechanisms on the same side of the machine frame cabin, the tail ends of the output shafts of the upper and lower two driving motors of one rotor wing mechanism incline to the front side of the machine frame cabin, the tail ends of the output shafts of the upper and lower two driving motors of the other rotor wing mechanism incline to the back side of the machine frame cabin, the turning directions of the driving motors on the upper sides of the first and second rotor wing mechanisms are opposite, and

And in a pair of left and right rotor wing mechanisms close to the front side or the rear side of the rack cabin, the tail ends of output shafts of driving motors of the pair of rotor wing mechanisms incline towards the front side or the rear end of the rack cabin.

Furthermore, 4 groups of rotor wing mechanisms are arranged on the left side and the right side of the machine frame cabin.

Further, the included angle alpha is 2-10 degrees.

Further, the included angle α is 4 °.

Further, the horn is a carbon fiber composite round tube, and the housing of the machine frame cabin and the propeller are made of carbon fiber composite materials;

and a steel undercarriage is arranged at the bottom of the engine frame cabin.

Furthermore, a plurality of regular hexagon socket joints are arranged on two sides of the machine frame cabin, and a regular hexagon hollow metal socket joint capable of being inserted into the regular hexagon socket joints is fixed at one end of the machine arm;

the regular hexagon socket and the sleeve are both provided with locking mechanisms.

Further, the propeller protection device is arranged in the center of the lower propeller of each group of rotor wing mechanisms and is a hollow conical cylinder which is coaxial with the lower driving motor and extends downwards, and the conical cylinders of each group of rotor wing mechanisms are the same in length.

Further, the motor mounting seat is a hollow rectangular metal frame body.

Furthermore, the included angles between two adjacent horn on the same side of the machine frame cabin are different from each other.

Further, the driving motor is a brushless motor.

Compared with the prior art, the invention has the beneficial effects that:

1. by adopting the layout of multiple shafts and double propellers, the load-carrying capacity of the unmanned aerial vehicle is greatly improved under the condition that the overall size of the multi-rotor unmanned aerial vehicle is not increased. And the windward area of the unmanned aerial vehicle is reduced, the air resistance borne by the unmanned aerial vehicle is reduced, and the flying speed is increased.

2. And a multi-shaft coaxial double-paddle layout is adopted, so that the control and power redundancy are strong. Under the condition of dismantling a plurality of propellers at random, the multi-rotor unmanned aerial vehicle with multiple coaxial double propellers of multiple shafts still can be kept stable, self-rotation cannot occur, operating torque in pitching and rolling directions is achieved, and the multi-rotor unmanned aerial vehicle with the multiple coaxial double propellers of multiple shafts can be guaranteed to be emergently and safely forced to land.

3. The machine frame cabin is positioned on the same horizontal plane with the motor and the propeller, so that the efficiency is improved, and the safety risk caused by the overhead arrangement of the machine frame cabin is avoided, or the air flow of the propeller is interfered and the efficiency is reduced due to the underneath arrangement of the machine frame cabin.

4. Can peg graft the horn has been designed, under non-user state such as unmanned aerial vehicle transportation, can dismantle the horn, further reduces unmanned aerial vehicle's size, reduces unmanned aerial vehicle's occupation of land space.

5. Designed the steel undercarriage that prevents turning on one's side, it is big with the area of contact on ground, manned many rotor unmanned aerial vehicle are difficult for taking place to empty during the landing.

6. Designed screw protection device, also can not incline, can not harm the screw when guaranteeing the unmanned aerial vehicle fuselage slope, safer.

7. Designed along the motor cabinet of horn axle slope, guaranteed that manned many rotor unmanned aerial vehicle has stronger driftage moment, promoted the flexibility that unmanned aerial vehicle controlled by a wide margin.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is an embodiment of an eight-axis coaxial twin-propeller multi-rotor drone provided by the present invention;

FIG. 2 is a fragmentary view of FIG. 1 showing a schematic view of the horn and cockpit connection;

FIG. 3 is a perspective view of the first rotor mechanism (A rotor mechanism) and its horn in the forward left of the cockpit in FIG. 1;

FIG. 4 is a perspective view of the second rotor (B rotor) and its horn on the left side of the cockpit in FIG. 1;

figure 5 is a perspective view of a rotor mechanism corresponding to figure 3;

FIG. 6 is a cross-sectional view of the arm of the A rotor mechanism viewed from the axial direction toward the cockpit of the airframe;

FIG. 7 is a cross-sectional view of the horn of the B rotor mechanism looking in the axial direction toward the cockpit of the airframe;

figure 8 is a schematic illustration of a rotation direction corresponding to 8 of the rotor mechanisms of figure 1;

figure 9 shows a schematic view of the thrust direction generated by two propellers in a rotor mechanism a, exploded in the horizontal and vertical directions respectively;

fig. 10 is a schematic diagram showing the horizontal component of thrust generated by two propellers in the rotor mechanism a, and the horizontal component of thrust is offset with respect to clockwise and counterclockwise yaw moments generated by the unmanned aerial vehicle;

FIG. 11 is a schematic diagram showing thrust generated by the rotor mechanism A when the two propellers are not rotating at the same speed and the forces resolved in the horizontal and vertical directions respectively;

fig. 12 shows a schematic diagram of the yaw moment generated by the unmanned aerial vehicle due to different horizontal component forces of thrust generated when the rotation speeds of the two propellers of the rotor a mechanism are different, so that the unmanned aerial vehicle makes yaw motion.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

In the following description, for purposes of explanation, specific details are set forth, such as particular steps and particular structures, in order to provide a thorough understanding of the present invention. The following detailed description of the preferred embodiments of the invention, however, the invention can be practiced otherwise than as specifically described.

The invention provides a multi-axis coaxial double-propeller multi-rotor unmanned aerial vehicle, which consists of a rack cabin 1 and a plurality of groups of rotor wing mechanisms symmetrically arranged on two sides of the rack cabin 1, wherein each rotor wing mechanism is connected with the rack cabin 1 through a horn 2, each rotor wing mechanism comprises a motor mounting seat 5 fixedly connected with the horn 2, the motor mounting seat 5 is of a hollow structure, and one end of the motor mounting seat 5 is provided with a sleeve 6 connected with the horn 2;

a driving motor is arranged on the upper side and the lower side of the motor mounting seat 5, the steering directions of the upper driving motor and the lower driving motor are opposite, and a propeller is arranged on an output shaft of the driving motor; two driving motors of each rotor wing mechanism incline and are symmetrically arranged at the upper side and the lower side of a motor mounting seat 5 from top to bottom, and the included angle between the output shafts of the driving motors and the vertical plane where the axes of a connecting horn 2 of the driving motors are connected with each other is alpha, wherein, in any two adjacent front and rear rotor wing mechanisms at the same side of a rack cabin 1, the tail ends of the output shafts of the upper and lower driving motors of one rotor wing mechanism incline to the front side of the rack cabin 1, the tail ends of the output shafts of the upper and lower driving motors of the other rotor wing mechanism incline to the rear side of the rack cabin 1, the turning directions of the driving motors at the upper sides of the first and second rotor wing mechanisms are opposite, and in a pair of left and right rotor wing mechanisms close to the front side or the rear side of the rack cabin 1, the tail ends of the output shafts of the driving motors of the pair of the rotor wing mechanisms all incline to the front side or the rear end of the rack cabin.

With reference to fig. 1 and 7, the left and right sides of the cabin of the rack 1 are respectively provided with 4 groups of rotor wing mechanisms, the four groups of left rotor wing mechanisms are sequentially provided with a rotor wing mechanism a, a rotor wing mechanism B, a rotor wing mechanism C and a rotor wing mechanism D from front to back, and the four groups of right rotor wing mechanisms are sequentially provided with a rotor wing mechanism H, a rotor wing mechanism G, a rotor wing mechanism F and a rotor wing mechanism E from front to back. The four groups of rotor mechanisms on the left side have the upper propellers respectively represented as A1, B1, C1 and D1 and the lower propellers respectively represented as A2, B2, C2 and D2 in the order from front to back; the H, G, F, E four sets of rotor mechanisms on the right side are counted from front to back, the upper propellers are respectively represented as H1, G1, F1, E1, the lower propellers are respectively represented as H2, G2, F2, E2, wherein the rotation direction of the upper propellers is indicated by solid bold lines and the rotation direction of the lower propellers is indicated by hollow lines in order to better distinguish the upper and lower propellers in fig. 8. Fig. 3-4 show perspective views of the two rotor mechanisms AB, with the upper propeller a1 of rotor mechanism a being rotated by drive motor A3 and the lower propeller a2 being rotated by drive motor a 4; the upper propeller B1 of the B rotor mechanism is driven to rotate by a drive motor B3, and the lower propeller B2 is driven to rotate by a drive motor B4.

With reference to fig. 1 as an example, two rotor mechanisms AB on the left side of the aircraft cabin 1 are described as an example: the tail end of a motor output shaft of the rotor A mechanism inclines towards the front side of the rack cabin 1, and the motor output shaft of the rotor B mechanism inclines towards the rear side of the tail end rack cabin 1. In a pair of rotor wing mechanisms A and H at the front side of the machine frame cabin 1, the tail ends of motor output shafts of the rotor wing mechanism A and the rotor wing mechanism H incline towards the front side of the machine frame cabin 1; correspondingly, in a pair of rotor mechanisms D and E at the rear side of the machine frame cabin 1, the tail ends of motor output shafts of the rotor mechanisms D and E are inclined towards the direction of the rear side of the machine frame cabin 1.

It should be noted that the upper and lower motors of each set of rotor mechanism are connected to the electronic speed regulators through dedicated silica gel wires, and all the electronic speed regulators are connected to the battery through dedicated silica gel wires. On the wire that electronic governor and battery link to each other, use banana head plug connector to quick assembly disassembly silica gel line when dismouting horn 2.

The control logic of the present invention is further described below:

in the art, the propeller reaction torque is interpreted as: the rotor gives the air with the reaction torque (or the moment of torsion), and the air must be in the same time with the reaction torque that the size is equal, opposite direction act on the rotor (or the reaction torque) to transmit this reaction torque to the unmanned aerial vehicle organism through the rotor again. That is to say the screw of clockwise rotation, can give unmanned aerial vehicle a anticlockwise pivoted moment of torsion. The number of the propellers of the unmanned aerial vehicle is generally even, so that the number of the positive and negative propellers is equal, the rotating speeds of all the propellers are equal in the hovering state, and the reaction torques of the propellers can be mutually offset.

According to the invention, the two motors on the same rotor wing mechanism rotate in opposite directions, so that the efficiency loss is only caused by about 20%, and the load capacity can be improved without increasing the overall size of the unmanned aerial vehicle. In addition, the propeller of the invention comprises a positive propeller and a reverse propeller: in fig. 1 and 7, propellers H2, G1, F2, E1, D2, C1, B2 and a1 rotate counterclockwise to generate lift force, are positive propellers, and generate counter torque for clockwise rotation of the unmanned aerial vehicle while generating lift force; the propellers H1, G2, F1, E2, D1, C2, B1 and A2 rotate clockwise to generate lift force, and are counter propellers which can generate counter torque for the unmanned aerial vehicle to rotate anticlockwise while generating the lift force.

Fig. 6 and 7 are views of the rotor mechanism a and the rotor mechanism B respectively looking into the rack cabin 1 along the axial direction of the horn 2, and the installation angle formed by the installation angle of the motor and the vertical direction is about 4 degrees, so that the propeller tilts in different directions. The screw of slope installation can produce a horizontal component, and the torque that horizontal component produced unmanned aerial vehicle is unanimous with the anti-turn round direction that its rotation produced, consequently, can play the effect that increases unmanned aerial vehicle driftage moment, lets unmanned aerial vehicle have more driftage maneuverability. Therefore, the inclination directions of all the positive propellers are required to be leftward, and the clockwise control moment of the unmanned aerial vehicle is increased; the inclination direction of the counter-propeller is towards the right, and the counter-clockwise control moment of the unmanned aerial vehicle is increased. Specifically, in a view point viewed inward along boom 2, in fig. 1 and 7, motor output shafts of A, C, G, E propellers are both inclined forward and motor output shafts of B, D, H, F propellers are both inclined rearward, so that planes in which propellers H2, G1, F2, E1, D2, C1, B2 and a1 are located are inclined to the left (as viewed from the front of the propellers to the downward), and planes in which propellers H1, G2, F1, E2, D1, C2, B1 and a2 are inclined to the right (as viewed from the rear of the propellers to the downward). The eight-axis coaxial double-propeller unmanned aerial vehicle achieves forward and backward flight, roll movement and change of course angles of the aircraft in a mode of changing the motor rotating speed of each group of rotor wing mechanisms. In fig. 1, the control logic and the motion effect of the unmanned aerial vehicle in each direction are as follows:

1) For the height rise of the unmanned aerial vehicle, all the driving motors simultaneously increase the rotating speed.

2) For the unmanned aerial vehicle height descending, all the driving motors simultaneously reduce the rotating speed.

3) To the forward luffing of unmanned aerial vehicle, the two pairs of rotor mechanism motor speed of left and right sides of unmanned aerial vehicle front side reduces, and the two pairs of rotor mechanism motor speed of left and right sides increase of rear side, rotor mechanism A promptly, rotor mechanism B, rotor mechanism H, rotor mechanism G motor speed reduce, and rotor mechanism F, rotor mechanism E, rotor mechanism C, rotor mechanism D motor speed increase.

4) To unmanned aerial vehicle pitching motion backward, two pairs of rotor mechanism motor speed increases about the unmanned aerial vehicle front side, and two pairs of rotor mechanism motor speed decreases about the rear side, rotor mechanism A promptly, rotor mechanism B, rotor mechanism H, rotor mechanism G motor speed increase, and rotor mechanism F, rotor mechanism E, rotor mechanism C, rotor mechanism D motor speed decrease.

5) To unmanned aerial vehicle roll motion left, rotor mechanism H, rotor mechanism G, rotor mechanism F, the increase of rotor mechanism E rotational speed on unmanned aerial vehicle right side, the left rotor mechanism A of unmanned aerial vehicle, rotor mechanism B, rotor mechanism C, rotor mechanism D rotational speed reduce.

6) To unmanned aerial vehicle roll motion right, rotor mechanism H, rotor mechanism G, rotor mechanism F, the rotor mechanism E rotational speed on unmanned aerial vehicle right side reduce, and the left rotor mechanism A of unmanned aerial vehicle, rotor mechanism B, rotor mechanism C, the increase of rotor mechanism D rotational speed.

7) For the counterclockwise yaw movement of the unmanned aerial vehicle, the motor rotating speeds of the propeller H2, the propeller G1, the propeller F2, the propeller E1, the propeller D2, the propeller C1, the propeller B2 and the propeller A1 are reduced, and the counter torque generated by the unmanned aerial vehicle in the clockwise direction is reduced; in addition, the motor rotating speeds of the propeller H1, the propeller G2, the propeller F1, the propeller E2, the propeller D1, the propeller C2, the propeller B1 and the propeller A2 are increased, and the counter-clockwise torque generated by the unmanned aerial vehicle is increased, so that the unmanned aerial vehicle does counter-clockwise yaw motion.

8) For the clockwise yaw movement of the unmanned aerial vehicle, the motor rotating speeds of the propeller H2, the propeller G1, the propeller F2, the propeller E1, the propeller D2, the propeller C1, the propeller B2 and the propeller A1 are increased, and the counter torque generated by the unmanned aerial vehicle in the clockwise direction is increased; and the motor rotating speeds of the propeller H1, the propeller G2, the propeller F1, the propeller E2, the propeller D1, the propeller C2, the propeller B1 and the propeller A2 are reduced, and the counter-clockwise counter-torque generated by the unmanned aerial vehicle is reduced, so that the unmanned aerial vehicle does clockwise yaw motion.

In an alternative embodiment, the number of the rotor mechanisms on each side of the cabin 1 is even, and preferably, 4 sets of rotor mechanisms are arranged on the left side and the right side of the cabin 1, so that an eight-axis coaxial double-propeller multi-rotor unmanned aerial vehicle is formed.

Considering the relation between the size of the unmanned aerial vehicle and the maneuverability, the acceleration of the unmanned aerial vehicle is irrelevant to the size of the unmanned aerial vehicle, and the angular acceleration is inversely proportional to the radius of the body of the unmanned aerial vehicle, namely the larger the size of the unmanned aerial vehicle is, the smaller the yaw angular acceleration of the unmanned aerial vehicle is. Therefore, the unmanned aerial vehicle is large in size, the unmanned aerial vehicle is controlled to yaw only by the aid of the reaction torque of the propellers, and yaw control performance is poor. To solve this problem, the motor installation angle needs to be designed. In an alternative embodiment of the invention, the angle α (which may be considered as the motor mounting angle) is 2-10 °. Further preferably, the included angle α is 4 °. In the invention, the motor installation angle alpha is 4 degrees, the left motor and the right motor are provided with opposite propellers, thereby ensuring that the thrust generated by the propellers mainly balances gravity along the vertical direction and also ensuring that enough horizontal direction component force is generated. Therefore, when the unmanned aerial vehicle does not yaw, the horizontal component forces generated by the two coaxial motors can be mutually offset, and the unmanned aerial vehicle cannot spin; when the unmanned aerial vehicle does the action of yawing, one of them motor rotational speed increase, horizontal component increase, another motor rotational speed reduces, horizontal component reduces, can provide a yawing moment for manned many rotor unmanned aerial vehicle, increases unmanned aerial vehicle's driftage manipulation performance.

As shown in fig. 9-10, taking the a rotor mechanism as an example: a1 is a propeller rotating anticlockwise and can provide moment for the unmanned aerial vehicle to rotate clockwise; a2 is a propeller rotating clockwise and can give a moment to the unmanned aerial vehicle to rotate anticlockwise. Looking inward along the horn, A1 is angled to the left and A2 is angled to the right. The thrust generated by the propeller can be resolved both horizontally and vertically. In the top view of fig. 10, the horizontal component force 1 generates a clockwise moment on the drone. The horizontal component force 2 generates a moment in the counterclockwise direction for the unmanned aerial vehicle.

Therefore, the motor mounting angle brings extra increased moment to the motor propeller, and the yaw motion of the unmanned aerial vehicle can be better controlled through the rotating speed. As in fig. 11-12, during yaw motion, the rotation speed of propellers a1, B2, C1, D2, E1, F2, G1, H2 increases; the rotating speeds of the propellers A2, B1, C2, D1, E2, F1, G2 and H1 are reduced, and the unmanned aerial vehicle makes clockwise yaw motion.

In an alternative embodiment, the horn 2 is a carbon fiber composite round tube, and the housing of the machine frame cabin 1 and the propeller are made of carbon fiber composite. The screw is major diameter carbon fiber screw, has higher intensity, less quality and inertia to manned many rotor unmanned aerial vehicle can realize self attitude control through the motor speed governing.

A steel undercarriage 3 is arranged at the bottom of the machine frame cabin 1, and preferably, the undercarriage 3 is made of steel and has the function of absorbing impact vibration. The area enclosed by the undercarriage 3 is large, and the unmanned aerial vehicle is not easy to tip over when taking off or landing in a side flight mode.

In an alternative embodiment, a plurality of regular hexagon sockets 11 are disposed on both sides of the rack cabin 1, and a regular hexagon hollow metal socket 21 that can be inserted into the regular hexagon socket 11 is fixed at one end of the horn 2, as shown in fig. 2. The regular hexagon socket 11 and the sleeve 6 are both provided with locking mechanisms, as shown in fig. 5, the side wall of the sleeve 6 is provided with an axial opening, the side walls of the sleeve 6 at the upper side and the lower side of the opening are welded with screw locking blocks, and the sleeve and the horn are tightly fixed through bolts.

In an alternative embodiment, as shown in fig. 3-4, a propeller protector 4 is disposed centrally on the lower propeller of each set of rotor mechanisms, and propeller protector 4 is a hollow conical cylinder extending coaxially and downwardly from the lower drive motor, wherein the conical cylinders of each set of rotor mechanisms are the same length. Preferably, the higher metal material of specific strength should be selected for use to screw protection device 4, and should have good axiality with motor, screw pivot during the installation, prevents to produce vibration, influences the coaxial many rotor unmanned aerial vehicle normal flight of double-oar of multiaxis. When many rotor unmanned aerial vehicle fuselages of manned incline, the screw protection device 4 of installation under the motor can be preferred and the ground point contact, plays the effect of support, has avoided the screw to beat ground, receives the condition emergence of damage, plays the effect of protection screw and passenger.

In an alternative embodiment, the motor mounting base 5 is a hollow rectangular metal frame, as shown in fig. 5, for reducing weight.

In an alternative embodiment, the angles between two adjacent arms 2 on the same side of the rack cabin 1 are different from each other, that is, the angle between the arms of the rotor mechanisms a and B, the angle between the arms of the rotor mechanisms B and C, and the angle between the arms of the rotor mechanisms C and D are different from each other. In an alternative embodiment, the drive motor is a brushless motor.

The unmanned aerial vehicle body with the multiple shafts, the coaxial double propellers and the multiple rotors is made of carbon fiber composite materials, so that the self weight of the unmanned aerial vehicle is greatly reduced; the tail end of the arm 2 is provided with a plurality of pairs of motors which rotate in opposite directions, and the rotation can provide a vertical upward lifting force for the unmanned aerial vehicle, so that the load-bearing performance of the unmanned aerial vehicle is improved under the condition that the overall size of the unmanned aerial vehicle is not increased; the brushless motor has a certain mounting angle, so that the brushless motor can generate component force in the horizontal direction, the direction of torque generated by the component force on the unmanned aerial vehicle is consistent with the direction of reaction torque generated by the rotation of the propeller, the yaw control moment of the unmanned aerial vehicle is increased, and the yaw control performance of the unmanned aerial vehicle is improved; a propeller protection device 4 is arranged below the lower-layer motor and the propeller, so that when the body of the unmanned aerial vehicle inclines, the propeller protection device 4 is preferentially contacted with the ground to form a new support plane, and the unmanned aerial vehicle is prevented from overturning and damaging the propeller; the undercarriage 3 of high tenacity can absorb the energy when unmanned aerial vehicle descends, reduce the impact, guarantee passenger's safety.

The above description is that of the preferred embodiment of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, in which devices and structures not described in detail are understood to be implemented in a manner that is conventional in the art; those skilled in the art can make many possible variations and modifications to the disclosed solution, or modify the equivalent embodiments with equivalent variations, without departing from the scope of the solution, without thereby affecting the spirit of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are within the scope of the technical solution of the present invention, unless the technical essence of the present invention is not departed from the content of the technical solution of the present invention.

Claims

1. A multi-shaft coaxial double-propeller multi-rotor unmanned aerial vehicle is composed of a rack cabin and a plurality of groups of rotor wing mechanisms symmetrically arranged on the left side and the right side of the rack cabin, and each rotor wing mechanism is connected with the rack cabin through a horn;

two driving motors of each rotor wing mechanism are inclined and are arranged at the upper side and the lower side of the motor mounting seat in a mirror symmetry manner, the included angles between the output shafts of the driving motors and the vertical plane where the axes of the self-connected machine arms are positioned are both alpha, wherein,

establish in the frame passenger cabin with two arbitrary rotor mechanisms in front and back adjacent as first rotor mechanism, second rotor mechanism, the end of two upper and lower driving motor output shafts of first rotor mechanism all inclines to frame passenger cabin front side, the end of two upper and lower driving motor output shafts of second rotor mechanism all inclines behind the frame passenger cabin, first, second rotor mechanism upside driving motor turn to opposite to

The tail ends of the output shafts of the lower driving motors of the left and right rotor wing mechanisms close to the front side of the rack cabin are inclined towards the front side of the rack cabin, and the tail ends of the output shafts of the lower driving motors of the left and right rotor wing mechanisms close to the rear side of the rack cabin are inclined towards the rear side of the rack cabin;

the lower screw center of every rotor mechanism of group all disposes screw protection device, screw protection device is the hollow circular cone cylinder coaxial and downwardly extending with lower driving motor output shaft, and wherein the circular cone cylinder's of every rotor mechanism of group length is the same.

2. A multi-axis co-axial, twin-paddle, multi-rotor drone according to claim 1, with 4 sets of rotor mechanisms on each side of the cockpit.

3. A multi-axis co-axial, twin-paddle, multi-rotor drone according to claim 2, characterised in that the angle α is between 2 ° and 10 °.

4. A multi-axis co-axial, twin-paddle, multi-rotor drone according to claim 3, characterised in that said angle α is 4 °.

5. The multi-axis coaxial twin-paddle multi-rotor drone of claim 1, wherein the horn is a carbon fiber composite round tube, the frame cockpit housing and propellers are carbon fiber composite;

and a steel undercarriage is arranged at the bottom of the engine frame cabin.

6. The multi-axis coaxial double-propeller multi-rotor unmanned aerial vehicle as claimed in claim 5, wherein a plurality of regular hexagonal sockets are arranged on both sides of the cabin, and a regular hexagonal hollow metal socket which can be inserted into the regular hexagonal sockets is fixed at one end of the horn;

7. The multi-axis coaxial twin-paddle multi-rotor drone of claim 1, wherein the motor mount is a hollowed rectangular metal frame.

8. The multi-axis coaxial twin-propeller multi-rotor drone of claim 1, wherein the angles between two adjacent arms on the same side of the frame capsule differ from each other.

9. The multi-axis coaxial twin-paddle multi-rotor drone of claim 1, wherein the drive motors are brushless motors.