CN117416506A

CN117416506A - Vertical take-off and landing aircraft and control method thereof

Info

Publication number: CN117416506A
Application number: CN202311677618.7A
Authority: CN
Inventors: 沙永祥; 薛松柏; 谢晒明; 许兆华; 骆俊昌; 周文杰; 王长云; 李唐
Original assignee: Sichuan Wofei Changkong Technology Development Co ltd; Zhejiang Geely Holding Group Co Ltd
Current assignee: Sichuan Wofei Changkong Technology Development Co ltd; Zhejiang Geely Holding Group Co Ltd
Priority date: 2023-12-07
Filing date: 2023-12-07
Publication date: 2024-01-19

Abstract

The invention provides a vertical take-off and landing aircraft and a control method thereof, wherein the vertical take-off and landing aircraft comprises: fuselage and 2N rotor that tilt. Wings are arranged on two sides of the fuselage, a tail fin is arranged at the tail part of the fuselage, and an elevator is arranged on the tail fin; 2N tilting rotors symmetrically arranged on two sides of the fuselage, and part of the 2N tilting rotors is positioned on the tail wing; wherein N is a natural number greater than or equal to 2, and in the vertical take-off and landing state, the projection of the propellers of the 2N tilt rotors on the horizontal plane is centrally symmetrical about a point B, the point B and a gravity center point G of the vertical take-off and landing aircraft are both positioned in a symmetrical plane of the fuselage, the point B is positioned on one side of the point G, which is close to the tail wing, and in the process of transition of the vertical take-off and landing aircraft from the vertical take-off and landing state to the cruising state, the point G and the point B are both moved along the symmetrical plane towards one side, which is close to the nose, and the point B is always positioned on one side, which is close to the tail wing, of the point G. This arrangement allows for a better trim pitch capability for a vertical takeoff and landing aircraft.

Description

Vertical take-off and landing aircraft and control method thereof

Technical Field

The invention relates to the technical field of aircrafts, in particular to a vertical take-off and landing aircraft and a control method thereof.

Background

The vertical take-off and landing fixed wing aircraft (distributed propulsion type) not only has the vertical take-off and landing capability of a helicopter, but also has the horizontal efficient and high-speed flight capability of the fixed wing, is quieter, comfortable and economical compared with the helicopter, is more efficient and longer in voyage compared with a plurality of rotor wings, can take off and land vertically on a take-off and landing platform in a city compared with the fixed wing, and is an excellent choice for urban aerial travel. However, in the existing vertical take-off and landing aircraft, when a rotor wing is arranged on a tail wing, air flow generated by the rotor wing and air flow generated by the tail wing are mutually interfered, so that pitch control is easy to be difficult, and unpredictable technical difficulty is brought to flight control of the vertical take-off and landing aircraft.

Disclosure of Invention

In view of the shortcomings of the prior art, the invention provides a vertical take-off and landing aircraft and a control method thereof, so as to solve the problems that in the existing vertical take-off and landing aircraft, airflow interference between a tail wing tilt-up rotor wing and a tail wing is large, and pitch control is difficult to carry out.

To achieve the above and other related objects, the present invention provides a vertical takeoff and landing aircraft comprising: fuselage and 2N rotor that tilt. Wings are arranged on two sides of the fuselage, a tail fin is arranged at the tail part of the fuselage, and an elevator is arranged on the tail fin; 2N tilting rotors are symmetrically arranged on two sides of the fuselage, and part of 2N tilting rotors are positioned on the tail wing; and when the vertical take-off and landing aircraft is in a modal change process, the point G and the point B move along the symmetry plane, and the point B is always positioned on one side of the point G, which is close to the tail wing, of the vertical take-off and landing aircraft.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, during flight, the axis of rotation of any one of said tiltrotors on said tail wing and the axis of rotation of any one of said tiltrotors at other locations are projected non-parallel on the plane of symmetry of said fuselage.

In an embodiment of the vertical takeoff and landing aircraft of the present invention, in a cruising state and/or a drooping state and/or a mode transition state, there is a first difference between the tilting speed of any one of the tilting rotors on the tail wing and the tilting speed of any one of the tilting rotors at other positions, and the first difference is not equal to 0.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, at cruise conditions and/or in a drooping condition and/or in a mode transition condition, there is a second difference between the rotational speed of any one of said tiltrotors on said tail wing and the rotational speed of any one of said tiltrotors at other positions, and said second difference is not equal to 0.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, the vertical takeoff and landing aircraft is pitch controlled by the following method:

during flight, distributing the pitch control proportion of the elevator to 2N tilting rotors according to the current airspeed or dynamic pressure;

And respectively controlling the elevator and the 2N tilting rotors according to the pitching control proportion so as to realize pitching balancing and operation.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, controlling 2N of said tiltrotors according to said pitch control ratio includes:

differentially adjusting the pitching moment to perform pitching balancing and manipulation through the tilting angle difference between the tilting rotor on the tail wing and any other tilting rotor;

and/or differentially adjusting the pitching moment to pitch trim and maneuver through the rotational speed differential of the tiltrotor on the tail with any of the other tiltrotors;

and/or differentially adjusting the pitching moment to pitch trim and maneuver through the difference in pitch speed of the tiltrotor on the tail and any of the other tiltrotors.

In an embodiment of the vertical takeoff and landing aircraft of the present invention, the vertical takeoff and landing aircraft includes four tiltrotors, four tiltrotors are symmetrically mounted on both sides of the fuselage, two of the tiltrotors are symmetrically mounted on the wing with respect to the fuselage, and the other two tiltrotors are symmetrically mounted on the tail wing.

In an embodiment of the vertical takeoff and landing aircraft of the present invention, the vertical takeoff and landing aircraft includes six tiltrotors, six tiltrotors are symmetrically mounted on both sides of the fuselage, four of the tiltrotors are symmetrically mounted on the wing with respect to the fuselage, and the other two tiltrotors are symmetrically mounted on the tail wing.

In an embodiment of the vertical takeoff and landing aircraft, the tail wing is a V-shaped tail wing, the two tilt rotors on the tail wing are full tilt rotors, and the two full tilt rotors are respectively arranged on wing tips on two sides of the upper part of the V-shaped tail wing.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, two tiltrotors are provided at the wing tips of the wings, and the tiltrotors located at the wing tips of the wings are all tiltrotors.

In an embodiment of the vertical take-off and landing aircraft, the vertical take-off and landing aircraft further comprises 2M fixed rotors, wherein M is a natural number greater than or equal to 2, and 2M fixed rotors are symmetrically arranged on the wings on two sides of the fuselage and are positioned on the outer sides of the tilting rotors; in the vertical take-off and landing state, the projection of all the fixed rotors on the horizontal plane is centrally symmetrical about the point A, the point A is positioned in the symmetrical plane of the fuselage, the point G is positioned on one side of the point A close to the nose or coincides with the point A in the process of modal change of the vertical take-off and landing aircraft, and the point B is always positioned on one side of the point A close to the tail wing.

in the flying process, distributing an elevator, 2N tilting rotors and the pitching control proportion of 2M fixed rotors according to the current airspeed or dynamic pressure;

and respectively controlling the elevator, the 2N tilting rotors and the 2M fixed rotors according to the pitching control proportion so as to realize pitching balancing and operation.

In an embodiment of the vertical takeoff and landing aircraft of the present invention, four fixed rotors are symmetrically installed at two sides of the fuselage, four tilting rotors are located at inner sides of the four fixed rotors, two of the tilting rotors are symmetrically installed on the tail wing, and two of the tilting rotors located on the tail wing are all tilting rotors.

In an embodiment of the vertical take-off and landing aircraft, the tail wing is a V-shaped tail wing, two tilt rotors are mounted on the V-shaped tail wing, the two tilt rotors are mounted at wing tips of the V-shaped tail wing respectively, in a vertical take-off and landing state, the distance between the rotation center of the tilt rotor on the tail wing and the front edge of the wing tip of the V-shaped tail wing is t1, and the chord length of the wing tip of the V-shaped tail wing is t2, wherein the ratio of t1 to t2 is 15% -40%.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, said tiltrotor on said tail is a full tiltrotor; the tiltrotor located beyond the tail wing is a partial tiltrotor.

In an embodiment of the vertical takeoff and landing aircraft of the present invention, a tilt rotor is provided on a wing tip of the wing, and the tilt rotor on the tail wing and the tilt rotor on the wing tip of the wing are all tilt rotors.

In an embodiment of the vertical takeoff and landing aircraft of the present invention, the full tilt rotor includes a first rotor and a power pod, the first rotor is connected to the power pod, the power pod is rotatably connected to the tail wing or the wing, and the power pod tilts synchronously with the first rotor during tilting of the first rotor.

In an embodiment of the vertical take-off and landing aircraft of the present invention, the elevator includes a rudder plate rotatably connected to the tail of the tail wing or the fuselage, and a rudder body driving device for driving the rudder plate to rotate so as to adjust the direction of the vertical take-off and landing aircraft.

The invention also provides a control method of the vertical take-off and landing aircraft, which comprises the following steps: fuselage and 2N rotor that tilt. Wings are arranged on two sides of the fuselage, a tail fin is arranged at the tail part of the fuselage, and an elevator is arranged on the tail fin; 2N tilting rotors are symmetrically arranged on two sides of the fuselage, and part of 2N tilting rotors are positioned on the tail wing; the projection of the propellers of the 2N tilting rotors on the horizontal plane is centrally symmetrical about a point B in a vertical take-off and landing state, the point B and the gravity center G of the vertical take-off and landing aircraft are both positioned in the symmetrical plane of the fuselage, the point B is positioned on one side of the point G, which is close to the tail wing, and the point G and the point B move along the symmetrical plane in the process of modal change of the vertical take-off and landing aircraft; specifically, in the transition of the vertical take-off and landing aircraft from the vertical take-off and landing state to the cruise state, the point G and the point B both move along the symmetrical plane towards the side close to the nose, and the point B is always located at the side of the point G close to the tail wing. The control method comprises the following pitching control process:

Distributing pitch control proportions of the elevator and 2N tilting rotors according to current airspeed or dynamic pressure;

and respectively controlling the elevator and 2N tilting rotors according to the pitching control proportion so as to realize pitching balancing and operation.

In one embodiment of the control method of the present invention, before distributing the pitch control ratio of the elevator to 2N of the tiltrotors according to the current airspeed or dynamic pressure, the control method further comprises the following rotor control procedure:

acquiring the current tilting position of each tilting rotor;

if the current tilting position is inconsistent with the set cruising position, acquiring the current airspeed or dynamic pressure of the corresponding tilting rotor under the current tilting position, and judging whether the current airspeed or dynamic pressure is equal to or greater than a preset threshold under the current tilting position;

if the current airspeed or dynamic pressure is equal to or greater than a preset threshold value at the current tilting position, controlling the tilting rotor to tilt to a preset next position;

the rotational speed of 2N tilting rotors is gradually increased.

In an embodiment of the control method of the present invention, the vertical take-off and landing aircraft further includes 2M fixed rotors, where M is a natural number greater than or equal to 2; 2M fixed rotor around 2N rotor distributes that verts, in the rotor control process, in the process of progressively increasing the rotational speed of 2N rotors that verts, still include: the rotational speed of the 2M fixed rotors is gradually reduced to the set rotational speed.

In an embodiment of the control method of the present invention, the following take-off control procedure is further included before the rotor control:

tilting 2N of said tiltrotors to an axis of rotation vertically or obliquely upward;

deflecting the lifting rudder downwards;

and starting 2M fixed rotors and 2N tilting rotors, and sending out a flat flight instruction when the vertical take-off and landing aircraft reaches a set height.

In an embodiment of the control method of the present invention, the vertical takeoff and landing aircraft further includes 2M fixed rotors, wherein the 2M fixed rotors are distributed around the 2N tilting rotors, and the following takeoff control procedure is further included before the pitch control ratio of the elevator to the 2N tilting rotors is distributed according to the current airspeed or dynamic pressure:

tilting 2N of said tiltrotors to an axis of rotation horizontally forward;

deflecting the lifting rudder downwards;

In an embodiment of the control method of the present invention, after the takeoff control process, the following rotor control process is further included before the pitch control: the rotating speed of 2N tilting rotors is gradually increased, a forward flight command is sent, and the rotating speed of 2M fixed rotors is gradually reduced to a set rotating speed.

In an embodiment of the control method of the present invention, in the rotor control process, after gradually reducing the rotational speeds of the 2M fixed rotors to the set rotational speed, the method further includes controlling the elevator to return to zero according to the current airspeed or dynamic pressure, and gradually participating in the pitch control process.

In an embodiment of the control method of the present invention, a ground preparation process is further included before the takeoff control process, and the ground preparation process includes: and starting the vertical take-off and landing aircraft, powering up and detecting the system, and confirming the full-stroke state of the servo system.

In an embodiment of the control method of the present invention, according to the pitch control ratio, controlling the elevator and the 2N tilt rotors respectively to implement pitch balancing and manipulation includes: the pitching moment is differentially regulated for pitch balancing and manipulation by the tilting speed difference and/or the tilting angle difference between the tilting rotors with different positions of the gravity centers and/or the rotation speed difference of the tilting rotors.

In an embodiment of the control method of the present invention, the control method further includes: and (5) sequentially repeating the rotor wing control process and the pitching control process until the tilting rotor wing tilts to the cruising position, and completing taking off and leveling off.

The vertical take-off and landing aircraft is provided with elevators and 2N tilting rotors, when in a vertical take-off and landing state, the projections of the propellers of the 2N tilting rotors on a horizontal plane are centrosymmetric about a point B, the point B and a gravity center G point of the vertical take-off and landing aircraft are both positioned in a symmetrical plane of the aircraft body, and the point B is positioned at one side of the point G, which is close to the tail wing. And in the mode change process of the vertical take-off and landing aircraft, the point B is always positioned at one side of the point G, which is close to the tail wing. With this arrangement, the centre of gravity G of the vertical takeoff and landing aircraft and the centre of symmetry B of the tiltrotor are not coincident, and in particular, both the G and B points move along the symmetry plane toward the nose side during the transition of the vertical takeoff and landing aircraft from the vertical takeoff and landing state to the cruise state. Therefore, the traction force generated by the front-gravity-center tilt rotor wing is smaller to the moment of the gravity center G point, the traction force generated by the rear-gravity-center tilt rotor wing is larger to the moment of the gravity center G point, and the moment difference of the front-and-back tilt rotor wings can resist the partial head-up moment generated by the action of the tail wing tilt rotor wing upwash zone on the tail wing, so that the difficulty of pitching operation can be reduced. Therefore, under the condition that the rotating speeds of the tilting rotors are the same at the front side and the rear side of the gravity center G point, because the length difference of the moment arm on the gravity center G point can generate low head moment, the head lifting moment generated by the action of the tilting rotor washing area on the tail wing can be counteracted or partially counteracted by the low head moment, so that the vertical take-off and landing aircraft can better balance the pitching moment under the condition that the front and rear rotor speeds are consistent.

According to the control method, the elevator and the pitching control proportion of 2N tilting rotors are distributed according to the current airspeed or dynamic pressure, and pitching control can be realized through linkage of the elevator and the 2N tilting rotors.

Drawings

In order to more clearly illustrate the embodiments of the invention or the solutions of the prior art, the drawings which are necessary for the description of the embodiments or the prior art will be briefly described, it being evident that the drawings in the following description are only some embodiments of the invention and that other embodiments can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is an isometric view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to an embodiment of the present invention;

FIG. 2 is a side view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to an embodiment of the present invention;

FIG. 3 is an isometric view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to another embodiment of the present invention;

FIG. 4 is a side view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to another embodiment of the present invention;

FIG. 5 is an isometric view of a vertical takeoff and landing aircraft in a cruise condition according to a further embodiment of the present invention;

FIG. 6 is an isometric view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to another embodiment of the present invention;

FIG. 7 is a top view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to another embodiment of the present invention;

FIG. 8 is a side view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to another embodiment of the present invention;

FIG. 9 is a rear view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to still another embodiment of the present invention;

FIG. 10 is a partial view of a full tilt rotor;

FIG. 11 is a partial view of the full tiltrotor after removal of the nacelle housing;

FIG. 12 is a top view of the full tiltrotor with the nacelle housing removed;

FIG. 13 is a cross-sectional view of D-D of FIG. 12;

FIG. 14 is another view of the tilt rotor after removal of the nacelle housing;

FIG. 15 is a three-dimensional view in another direction of the full tiltrotor after removal of the nacelle housing;

FIG. 16 is a cross-sectional F-F view of FIG. 14;

FIG. 17 is a P-P cross-sectional view of FIG. 14;

FIG. 18 is a partial view of a full tilt rotor on the tail wing in a cocked state with a rudder plate chord length of 30%;

FIG. 19 is a partial view of a full tilt rotor on the tail wing in a cocked state with a rudder plate chord length of 60%;

FIG. 20 is a partial view of a full tilt rotor on the tail wing in a cocked state with a rudder plate chord length of 100%;

FIG. 21 is a partial view of a full tilt rotor on the tail in cruise condition;

FIG. 22 is a partial view of a full tilt rotor on the tail in a climb-up condition;

FIG. 23 is a diagram of the rotational path of an elevator on the tail;

FIG. 24 is a top view of the tail wing in a vertical takeoff and landing condition of the aircraft;

FIG. 25 is a schematic diagram of the chord length ratio of the rudder plate of the tail wing and the deflection angle of the rudder plate;

FIG. 26 is a top view of the tail wing in a vertical takeoff and landing condition of the aircraft;

FIG. 27 is a graph showing the variation of pitching moment (dimensionless) of the whole machine with wind speed (dimensionless) according to the nacelle partial tilting and full tilting control method (CFD simulation result);

FIG. 28 is a flow chart of an embodiment of the vertical takeoff and landing aircraft of the present invention from a ground state to a cruise state;

FIG. 29 is a flow chart of a take-off and landing aircraft of an embodiment of the present invention;

FIG. 30 is a flow chart of pitch control of an embodiment of a vertical takeoff and landing aircraft of the present invention;

FIG. 31 is a flow chart of rotor control for an embodiment of a vertical takeoff and landing aircraft according to the present invention;

FIG. 32 is a flow chart of a takeoff control process for an embodiment of a vertical takeoff and landing aircraft according to the present invention;

FIG. 33 is a flow chart of a takeoff control process for an embodiment of a vertical takeoff and landing aircraft according to the present invention;

Fig. 34 is a top view of a vertical takeoff and landing aircraft in a vertical takeoff and landing state according to still another embodiment of the present invention.

Description of element reference numerals

10. A body; 20. a wing; 30. a tail wing; 31. an elevator; 311. a rudder plate; 41. a first tilt rotor; 411. a third horn; 42. a second tilt rotor; 421. a fourth horn; 43. a third tilt rotor; 44. a fourth tilt rotor; 441. a first rotor; 4411. a propeller; 4412. a rotation driving device; 4413. a fairing; 442. a power pod; 4421. tilting drive means; 4422. a rocker arm; 4423. a first shaft body; 4424. a second shaft body; 4425. a holding structure; 44251. slotting; 4426. a connecting rod; 4427. a first hinge shaft; 4428. a second hinge shaft; 4429. a driving arm; 4430. a bearing; 51. a first stationary rotor; 511. a first horn; 52. a second stationary rotor; 521. a second horn; 53. a third stationary rotor; 54. a fourth stationary rotor; 60. a plane of symmetry.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict. It is also to be understood that the terminology used in the examples of the invention is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the invention. The test methods in the following examples, in which specific conditions are not noted, are generally conducted under conventional conditions or under conditions recommended by the respective manufacturers.

Where numerical ranges are provided in the examples, it is understood that unless otherwise stated herein, both endpoints of each numerical range and any number between the two endpoints are significant both in the numerical range. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs and to which this invention belongs, and any method, apparatus, or material of the prior art similar or equivalent to the methods, apparatus, or materials described in the examples of this invention may be used to practice the invention.

It should be understood that the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like are used in this specification for descriptive purposes only and not for purposes of limitation, and that the invention may be practiced without materially departing from the novel teachings and without departing from the scope of the invention.

Referring to fig. 1 to 34, the present invention firstly provides a vertical take-off and landing aircraft, in which 2N tiltrotors are symmetrically arranged around the periphery of a fuselage 10, and an elevator is provided on a tail wing 30. The control of pitching moment of the vertical take-off and landing aircraft under a complex interference flow field can be improved by utilizing the position relation between the 2N tilting rotors and the gravity center, so that the control problem caused by air flow interference between the tilting rotors on the tail wing 30 and the tail wing 30 in the conventional vertical take-off and landing aircraft is solved.

Referring to fig. 1 to 7, the present invention provides a vertical takeoff and landing aircraft, comprising: fuselage and 2N rotor that tilt. The fuselage 10 is of a symmetrical structure, and has a symmetry plane 60 (i.e., a vertical plane in which the straight line O1-O2 is located in fig. 3) extending along the length direction of the fuselage 10, and the rest of the fuselage 10 is not limited in structure and shape, and can refer to the fuselage 10 structure of the existing vertical take-off and landing aircraft, and the fuselage 10 includes conventional operation systems of the aircraft, such as an avionics system, an flight control system, an electrical system, and a navigation system, which are not described herein. The wings 20 are disposed on two sides of the fuselage 10, the wings 20 on two sides are symmetrical with respect to the symmetry plane 60 of the fuselage 10, and the structure of the wings 20 can also refer to the fixed wing structure of the existing aircraft, which is not described herein. The tail part of the fuselage 10 is provided with a tail wing 30, and the tail wing 30 is integrally formed with or mechanically connected with the fuselage 10 and symmetrically arranged relative to a symmetry plane 60 of the fuselage 10. The tail wing 30 is provided with an elevator 31, and the installation position and structure of the elevator 31 may be various, for example, may be disposed at any suitable position on the tail wing 30, or may be any suitable elevator structure.

In key, referring to fig. 7,2N, the tiltrotors are mounted on two sides of the fuselage 10, N is a natural number greater than or equal to 2, 2N tiltrotors are symmetrically disposed about the symmetry plane 60 of the fuselage 10, and a part of 2N tiltrotors are mounted on the tail wing 30. In the vertical take-off and landing state, the projections of the propellers of the 2N tilting rotors on the horizontal plane are centrally symmetrical about a point B, the point B and a gravity center G point of the vertical take-off and landing aircraft are both positioned in a symmetrical plane of the fuselage, the point B is close to one side of the tail wing, the point G and the point B move along the symmetrical plane in the mode change process of the vertical take-off and landing aircraft, for example, in the transition process from the vertical take-off and landing state to the cruising state, the point G and the point B move along one side of the symmetrical plane close to the nose, and the point B is always positioned on one side of the point G close to the tail wing.

With the above layout, the gravity center G point of the vertical takeoff and landing aircraft and the symmetry center B point of the 2N tilting rotors do not coincide, and during the transition of the vertical takeoff and landing aircraft from the vertical takeoff and landing state to the cruising state, the G point and the B point both move along the symmetry plane 60 to the side close to the nose. Therefore, the moment of the traction force generated by the front-center-of-gravity tilt rotor wing on the center of gravity G is smaller, the moment of the traction force generated by the rear-center-of-gravity tilt rotor wing on the center of gravity G is larger, and the moment difference of the front-rear tilt rotor wing can resist the partial head-up moment generated by the action of the upper tilt rotor wing washing area of the tail wing 30 on the tail wing, so that the difficulty of pitching operation can be reduced. Therefore, under the condition that the rotating speeds of the tilting rotors are the same at the front side and the rear side of the gravity center G point, because the length difference of the moment arm on the gravity center G point can generate low head moment, the head lifting moment generated by the action of the tilting rotor washing area on the tail wing can be counteracted or partially counteracted by the low head moment, so that the vertical take-off and landing aircraft can better balance the pitching moment under the condition that the front and rear rotor speeds are consistent.

In the vertical take-off and landing aircraft of the present invention, in various states, such as a cruise state in which the aircraft flies in a horizontal direction, a take-off state in which the aircraft takes off and land in a vertical direction, and a mode transition state (including a transition from the take-off state to the cruise state and a transition from the cruise state to the take-off state), the rotation axes between the tilting wings may be disposed in parallel or may not be disposed in parallel. In some embodiments, during flight, the projection of the rotation axis of any one of the tiltrotors on the tail wing 30 and the rotation axis of any one of the other positions on the symmetry plane 60 of the fuselage 10 is not parallel, and different tiltrotors provide moments in different directions through the non-parallel rotation axes, so as to control the pitching moment of the whole vertical takeoff and landing aircraft.

Although the pitch control may be performed by other means by the same pitch speed between the respective tiltrotors, in an embodiment of the vertical-take-off and landing aircraft of the present invention, in each state, such as a cruise state in which the aircraft flies in a horizontal direction, a heave state in which the aircraft takes off and land in a vertical direction, and a mode transition state (including a transition from the heave state to the cruise state and a transition from the cruise state to the heave state), there is a first difference between the pitch speed of any one of the tiltrotors on the tail wing 30 and the pitch speed of any one of the other positions, and the first difference is not equal to 0, and by setting a threshold value of the first difference, the pitch force of the vertical-take-off and landing aircraft in each state may be adjusted by the pitch of the tiltrotors, so as to obtain a larger pitch control moment.

Although the rotational speeds of the tiltrotors may be the same, and pitch control may be performed by other means, in one embodiment of the vertical takeoff and landing aircraft of the present invention, in each state, such as a cruise state in which the aircraft is flying in a horizontal direction, a heave state in which the aircraft is flying in a vertical direction, and a mode transition state (including a transition from the heave state to the cruise state and a transition from the cruise state to the heave state), there is a second difference between the rotational speed of any one of the tiltrotors on the tail 30 and the rotational speed of any one of the tiltrotors at other positions, and the second difference is not equal to 0. By setting the threshold value of the second difference value, the pitching force of the vertical takeoff and landing aircraft in each state can be adjusted through the rotation speed of the tilting rotor, so that a larger pitching control moment is obtained. It should be noted that, the first difference between the tilting speeds of the front tilt rotor (the tilt rotor located on the forward side of the tilt rotor on the tail 30) and the tilt rotor on the tail 30 may be combined with the second difference between the rotation speeds of the front tilt rotor and the tilt rotor on the tail 30, so as to implement the pitching moment control of various strategies.

Although the present invention may include only 2N tiltrotors as shown in fig. 1 to 4, preferably, referring to fig. 7, in another embodiment of the present invention, the vertical takeoff and landing aircraft includes 2M fixed rotors, where M is a natural number greater than or equal to 2, and M may be the same as or different from N. 2M fixed rotors are symmetrically arranged on the wings on two sides of the fuselage and are positioned on the outer sides of the tilting rotors; in the vertical take-off and landing state, the projection of all the fixed rotors on the horizontal plane is centrosymmetric about the point A, wherein the point A is positioned in the symmetrical plane of the fuselage and coincides with the point G or is positioned on one side of the point G, which is close to the tail wing. In the process of transition of the vertical take-off and landing aircraft from the vertical take-off and landing state to the cruise state, the point G and the point B move along the symmetrical surface towards one side close to the nose, the point G is positioned at one side close to the nose of the point A or coincides with the point A, and the point B is always positioned at one side close to the tail wing of the point A.

Specifically, the nose of the vertical take-off and landing aircraft is used for forward, the center B point of the 2N tilting rotors is positioned at the rear side of the center A point of the 2M fixed rotors, the distance from the A point to the B point is L2, L2 is more than 0, as the 2N tilting rotors tilt forward, the gravity center of the 2N tilting rotors, the gravity center G of the vertical take-off and landing aircraft and the symmetry center B point move towards the direction close to the nose, and the whole tilting process from the preset vertical take-off and landing position (for example, 90-degree tilting angle) of the 2N tilting rotors to the preset cruising position (for example, 0-degree tilting angle) is started, and L2 is always more than 0; meanwhile, the gravity center G of the vertical take-off and landing aircraft is positioned on the front side of the symmetry center B of the 2N tilting rotors and on the front side of the symmetry center A of the 2M fixed rotors, the distance from the A point to the G point is L1, L1 is more than or equal to 0, and along with forward tilting of the 2N tilting rotors, the gravity center G gradually moves forward, and the absolute value of L1 is also larger and larger. Under the layout, the gravity center of the vertical take-off and landing aircraft is not coincident with the symmetry center of the fixed rotor wing or the symmetry center of the tilting rotor wing, and in the process of transition from the vertical take-off and landing state to the cruising state of the vertical take-off and landing aircraft, the point G and the point B move along the symmetry surface towards one side close to the nose, the point G is positioned at one side close to the nose or coincides with the point A, the point B is always positioned at one side close to the tail wing 30, so that the moment of the traction force generated by the front-side tilt rotor wing and the fixed rotor wing on the gravity center G is smaller, the moment of the traction force generated by the rear-side tilt rotor wing and the fixed rotor wing on the gravity center G is larger, and the moment difference of the front-back rotor wings can resist the partial head-lifting moment generated by the action of the tilting rotor wing washing area on the tail wing, so that the difficulty of pitching operation can be reduced. Therefore, under the condition that the rotary wings or the tilting rotary wings are fixed on the front side and the rear side of the gravity center G point at the same rotating speed of the throttle, because the length difference of the moment arm on the gravity center G point can generate low head moment, the head lifting moment generated by the action of the tilting rotary wing washing area on the tail wing can be counteracted or partially counteracted by the low head moment, so that the vertical take-off and landing aircraft can better trim the pitching moment under the condition that the throttle of the front and rear rotary wings is consistent.

Further, in the tilting stage of the tilting rotor, because of aerodynamic interference, the vertical take-off and landing aircraft also generates an additional larger head-up moment, and in the tilting process of the tilting rotor, the gravity center G of the vertical take-off and landing aircraft gradually moves towards the nose along with the tilting process, and the symmetry center B of the tilting rotor gradually moves towards the nose, and because the gravity center G is always in front of the B, the moment difference between the tilting rotor on the front side of the gravity center G and the tilting rotor behind the gravity center G in the whole tilting stage can also generate a part of low head moment so as to offset or partially offset the head-up moment caused by the aerodynamic interference.

Further, in the tilting phase and the cruising phase, the gravity center point G is close to the front side relative to the point A and the point B, and the point B is always positioned on one side of the point A close to the tail wing 30, so that the aircraft has relatively large longitudinal and course static stability margin, has stronger capability of resisting extremely strong wind weather, and is safer in flight.

Referring to fig. 26, in an embodiment of the vertical takeoff and landing aircraft of the present invention, the tail wing 30 is a V-shaped tail wing, a third tilt rotor 43 is installed on one wing tip of the V-shaped tail wing, a fourth tilt rotor 44 is installed on the other wing tip of the V-shaped tail wing, and the third tilt rotor 43 and the fourth tilt rotor 44 are symmetrical with respect to a plane of symmetry 60 of the fuselage. In the vertical take-off and landing state, along the direction parallel to the rolling axis X of the aircraft, the distance between the rotation center of the tail wing tilt-up rotor wing and the front edge of the wing tip of the V-shaped tail wing is t1, and the chord length of the wing tip of the V-shaped tail wing is t2, wherein the ratio of t1 to t2 is 15% -40%. According to the structural strength stress analysis of the wing tip of the tail wing 30, the tilting mechanism is connected with the wing tip of the tail wing 30 within the range, the thickness of the tail wing 30 is thicker, and the stress condition of the tail wing 30 is better.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, said tiltrotor on said tail is a full tiltrotor; the tiltrotors located beyond the tail are part of the tiltrotors, and in other embodiments the tiltrotors located beyond the tail may be full tiltrotors, particularly where the tiltrotors are mounted on the wing tips. The existing tilting rotor comprises a rotor and a power nacelle 442, wherein a motor and control components can be installed in the power nacelle 442. The "partially tilting rotor" cuts off the nacelle 442, and during tilting of the rotor, the portion close to the rotor tilts along with the rotor, and the portion far from the rotor is fixed relative to the fuselage 10. In the "full tilt rotor" described above, the entire nacelle 442 tilts with the corresponding rotor. It should be noted that, if the installation conditions allow, all of the 2N tiltrotors may be full tiltrotors, but it is considered that the existing tiltrotors on the front fuselage 10 or the wing 20 of the tail wing 30 are mounted on the horn. Referring to fig. 1 to 6, in the embodiment of the present invention, the tilt rotor on the tail wing 30 is a full tilt rotor, and the tilt rotor on the fuselage 10 or the wing 20 on the front side of the tail wing 30 is a partial tilt rotor. The particular location and manner of mounting of portions of the tiltrotor on the wing 20 or fuselage 10 may be without limitation. For example, may be mounted directly to the wing 20, or may be mounted to the wing 20 or the fuselage 10 via a horn.

2N tiltrotors are symmetrically disposed about the fuselage 10 and the tail 30 is provided with a full tiltrotor. Because the full-tilt rotor is rotatably mounted on the tail wing 30 through the power nacelle 442, the power nacelle 442 and the rotor on the tail wing 30 are always in the same rotation axis when the full-tilt rotor tilts, so that the shielding area of the power nacelle 442 in the corresponding rotor is smaller when the vertical take-off and landing aircraft hovers, the area of the rotor for washing down to the tail wing 30 is smaller, the mutual interference between the air flow generated by the rotor and the air flow generated by the tail wing 30 is smaller, the head lifting moment borne by the aircraft is reduced when the aircraft hovers, and the control of the pitching moment of the vertical take-off and landing aircraft under a complex interference flow field is simpler.

In an embodiment of the vertical takeoff and landing aircraft of the present invention, the full tilt rotor structure may be any existing tilt rotor structure capable of implementing synchronous tilting of the power nacelle 442 along with the rotor, referring to fig. 10 and 18, the full tilt rotor includes a first rotor 441 and a power nacelle 442, the first rotor 441 is connected to the power nacelle 442, and the power nacelle 442 is rotatably connected to the tail wing 30 or the wing 20 and is synchronously tilted along with the first rotor 441 during tilting of the first rotor 441. The housing of the power pod 442 contains the power device, e.g., if in an electric-only configuration, it may contain a motor, an electronic control, a ring control, a tilting mechanism, etc.; in the case of the oil-powered configuration, the nacelle contains the engine, ECU, tilting mechanism, etc., although the present solution is preferably purely electric.

Referring to fig. 10, in an embodiment of the vertical takeoff and landing aircraft of the present invention, a fairing 4413 is disposed at the center of the first rotor 441, and the fairing 4413 is mounted on the windward side of the first rotor 441 for reducing air flow resistance, preferably, along the direction of extension of the rotation axis of the first rotor 441, the projection of the fairing 4413 covers the projection of the power nacelle 442. This arrangement reduces the impact of the power pod 442 on the rotor downwash during flight. It will be appreciated by those skilled in the art that the projection of the nacelle 442 may be partially within the projection of the fairing 4413 and may also function to partially reduce drag, but only to a lesser extent relative to the full coverage of the former.

The power pod 442 has a shape including, but not limited to, a revolution body, a square body, an ellipsoid, etc., preferably, in an embodiment of the vertical takeoff and landing aircraft of the present invention, the power pod 442 is a revolution body structure, and a revolution shaft of the revolution body structure is coaxially disposed with a rotation shaft of the first rotor 441; the surface of the power pod 442 is streamlined. This reduces the impact of the nacelle 442 on the corresponding rotor downwash during flight.

Referring to fig. 10 to 17, the first rotor 441 includes a propeller 4411 and a rotation driving device 4412, the propeller 4411 is mounted on an output shaft of the rotation driving device 4412, and the power pod 442 includes a pod housing 4431 and a tilting mechanism within the pod housing 4431, which drives the rotation driving device 4412 to tilt. The tilting mechanism of the present invention may be any suitable tilting mechanism capable of driving the power pod 442 and the rotation driving device 4412 to tilt synchronously, and preferably, in this embodiment, the tilting mechanism includes: a rocker arm 4422, a driving arm 4429, a tilting driving device 4421, and a link 4426. The tilting drive 4421 may be of any suitable type of construction having a rotary output shaft, for example, a steering engine, a combination of steering engine and speed reducer, etc., in which the tilting drive 4421 is a steering engine. The rocker 4422 is rotatably mounted on the tail wing 30, and one end of the rocker 4422, which is close to the rotation driving device 4412, is fixedly connected with the rotation driving device 4412; the driving arm 4429 is rotatably mounted on the tail wing 30, and the rotating shaft of the driving arm 4429 is parallel to the rotating shaft of the rocker arm 4422; the base of the tilting driving device 4421 is fixedly arranged on the tail wing 30, and the driving end of the tilting driving device 4421 drives the driving arm 4429 to rotate; one end of the connecting rod 4426 is hinged to the rocker arm 4422 through a first hinge shaft 4427, the other end of the connecting rod 4426 is hinged to the driving arm 4429 through a second hinge shaft 4428, and although the positions of the first hinge shaft 4427 and the second hinge shaft 4428 are not required to be provided with the bearing 4430, preferably, the bearing 4430 is arranged between the connecting rod 4426 and the first hinge shaft 4427, and the bearing 4430 is also arranged between the connecting rod 4426 and the second hinge shaft 4428, so that the tilting process can be more stable. The tilting mechanism can realize a double-shaft connection structure with the tail wing 30 through the rotating shaft of the rocker 4422 and the rotating shaft of the driving arm 4429, the moment born by the tilting mechanism can be increased by increasing the axial distance from the rotating shaft between the rocker 4422 and the tail wing 30 to the rotating shaft between the driving arm 4429 and the tail wing 30 so as to reduce the force born by a single rod, the torsion resistance of the mechanism is stronger, and the supporting rigidity of the mechanism is improved. The tilting mechanism is fixed on the aircraft by adopting the mode that the single-side support can be used, the driving requirement is reduced by the four-bar mechanism, meanwhile, the rigidity of the whole mechanism can be adjusted by adjusting the length proportion between the four bars, and the natural frequency can be adjusted very conveniently.

Referring to fig. 11 to 17, in this embodiment, a first shaft body 4423 and a second shaft body 4424 are fixedly disposed on the tail wing 30 and parallel to each other, one ends of the first shaft body 4423 and the second shaft body 4424 are fixed on the wing tip of the tail wing 30, the other ends of the first shaft body 4423 and the second shaft body 4424 are cantilevered, the rocker arm 4422 is rotatably mounted on the first shaft body 4423 through a bearing 4430, the driving arm 4429 is rotatably mounted on the second shaft body 4424 through a bearing 4430, the base of the tilting driving device 4421 is rotatably mounted on the first shaft body 4423 through a holding structure 4425 and is positioned along the axial direction of the first shaft body 4423, and the driving end of the tilting driving device 4421 is coaxial with the second shaft body 4424 and is fixedly connected with the driving arm 4429. The positioning and mounting of the tilting driving device 4421 can be realized jointly through the holding structure 4425 and the second shaft body 4424, and the mounting difficulty of the tilting mechanism in the housing of the power nacelle 442 can be reduced, so that the single-side mounting stability of the full tilting rotor is improved. In other embodiments, the tilting driving device 4421 may be fixedly disposed on the tail wing 30, and the output shaft of the tilting driving device 4421 may extend out to be fixedly connected with the driving arm 4429, so that the driving link 4426 drives the rocker arm 4422 to tilt. However, compared with the present embodiment, the arrangement mode occupies a larger space inside the tail wing 30, is not suitable for the situation that the wing profile is thinner or the internal equipment is more, and simultaneously causes the torque applied to the tilting drive device 4421 to be born by the mounting seat of the tilting drive device 4421, thereby having a larger requirement on the mounting strength of the tilting drive device 4421.

Referring to fig. 11 to 17, the first shaft body 4423 and the second shaft body 4424 may be further limited by the clasping structure 4425, so as to enhance the structural strength of the first shaft body 4423 and the second shaft body 4424 on the tail wing 30, so that the first shaft body 4423 and the second shaft body 4424 maintain a parallel positional relationship on the tail wing 30, ensure that the driving device and the rocker arm 4422 maintain on the same horizontal plane during the tilting driving process, and realize stable tilting driving of the driving device on the rocker arm 4422. One end of the holding structure 4425 is fixedly connected with the base body of the tilting drive device 4421, specifically, one end of the holding structure 4425 is arranged around the periphery of the base body of the tilting drive device 4421, more specifically, one end of the holding structure 4425 is fixedly connected with the base body of the tilting drive device 4421 and is coaxially arranged on the second shaft body 4424; the other end of the holding structure 4425 surrounds and holds the first shaft 4423, specifically, as shown in fig. 15, the other end of the holding structure 4425 is sleeved on the periphery of the first shaft 4423 in an interference manner so as to realize holding and fixing with the first shaft 4423, more specifically, a slit 44251 is formed in the other end of the holding structure 4425, the slit 44251 extends from the outer edge of the other end of the holding structure 4425 to the position of the inner wall abutting against the first shaft 4423, and the slit 44251 axially extends along the first shaft 4423. The other end of the holding structure 4425 utilizes the elastic expansion and contraction characteristics of the slit 44251 to realize surrounding holding of the first shaft body 4423 with different outer diameter sizes, and the tolerance range allowed by interference fit between the holding structure 4425 and the first shaft body 4423 is enlarged.

In the invention, the first shaft body 4423 and/or the second shaft body 4424 are hollow shafts, and can be threaded and connected with the cables and the pipelines, so that the cables and the pipelines are prevented from being damaged by irregularly swinging outside, and meanwhile, the moving range of the cables and the pipelines is reduced, and the cables are prevented from being damaged. Considering that the second shaft 4424 needs to bear a large load, in this embodiment, the first shaft 4423 is preferably a hollow shaft, and the second shaft 4424 is preferably a solid shaft, however, in other embodiments, if the second shaft 4424 can bear a large load, the second shaft 4424 may be a hollow shaft, or both the first shaft 4423 and the second shaft 4424 may be hollow shafts.

It should be noted that, considering that the single-side installation of the whole tilting mechanism, the longer extending distance of the first shaft 4423 may cause the bending moment of the first shaft 4423 to increase, and preferably, referring to fig. 12, in an embodiment, the first shaft 4423 and the tail wing 30 are installed with a matching surface 4432 that is longer along the axial direction, so that the installation length of the first shaft 4423 may be increased, the contact area between the first shaft 4423 and the tilting driving device base is increased, so as to balance the bending moment borne by the first shaft 4423, further reduce the bending deformation of the first shaft 4423, and improve the installation stability of the whole tilting mechanism.

In an embodiment of the invention, a distance from a rotation center of the tilting driving device 4421 to an axis of the second hinge shaft 4428 is a, a distance from an axis of the first hinge shaft 4427 to an axis of the second hinge shaft 4428 is b, a distance from a center of the first shaft 4423 to an axis of the first hinge shaft 4427 is c, a distance from a center of the first shaft 4423 to a center of the second shaft 4424 is d, a is smaller than b, c, and d, c is larger than b and d, respectively, and a sum of a and c is smaller than a sum of b and d. Therefore, once the tilting driving device 4421 is out of control, the output shaft of the tilting driving device 4421 is always in a forward or reverse rotating state, the rocker 4422 swings, namely the rocker 4422 rotates anticlockwise after rotating clockwise to the limit position and rotates clockwise after rotating anticlockwise to the limit position, the movable range of the tilting mechanism is limited, the tilting mechanism cannot rotate beyond the range to collide with other components to interfere with the other components, and the front end screw propeller of the tilting mechanism is prevented from colliding with the machine body and other structures to damage the machine body due to tilting overreach. Therefore, the invention can restrict the tilting angle range of the tilting mechanism by adjusting the length proportion of each part in the tilting mechanism, and simultaneously skillfully realizes the limit problem of the tilting mechanism, so that the limit position of forward rotation and the limit position of reverse rotation of the tilting mechanism are both at the same limit position of the connecting rod, the skillfully design not only can effectively ensure the safety of the mechanism, but also simplifies the design, does not need to additionally arrange a limit mechanism to limit the limit position, and greatly optimizes the installation space of the motion process of the transmission rod mechanism; specifically, by adjusting the length ratio of each part in the link mechanism to make the distance between the end axis (i.e., the axis of the second shaft 4428) of the driving arm 4429 and the axis of the first shaft 4423 equal in the initial angle state (i.e., the tilting minimum angle) and the final angle state (i.e., the tilting maximum angle), and at this time, the included angle between the end axis of the driving arm 4429 in the initial angle state and the axis composition plane of the first shaft 4423 and the end axis of the driving arm 4429 in the final angle state and the axis composition plane of the first shaft 4423 is equal to the angle ±5° of rotation of the rocker 4422, it is possible to realize that one limit point constrains two directions.

In the embodiment, the tilting mechanism has different reduction ratios at different tilting angles, so that the control precision requirements at different angles are realized, the structure is compact, and the space requirements are reduced in a centralized manner. Through the use of multiple connecting rods, the reduction ratio is changed along with the change of angles, the reduction ratio at a large load can be increased, the reduction ratio at a small load is reduced, the peak driving moment is reduced, and the driving requirement is reduced. The tilting driving device is of a rotary driving structure, and can amplify driving force through a brake or reduction ratio adjusting device in the tilting device, so that on one hand, torque born by an executing end can be overcome, and state maintenance at any position is realized, the current state position is maintained when driving fails, and the tilting driving device can continue to work after driving is recovered, and on the other hand, structural components can be arranged more intensively.

As shown in fig. 1 to 7 and fig. 20 to 23, in an embodiment of the helicopter according to the present invention, the rotation axis of the tilting rotor is tilted in the range of-20 ° to 110 ° with respect to the rotation axis X as a reference and with respect to the upward direction. Wherein, please refer to fig. 21,0 ° that the rotation axis of the tilting rotor extends forward along the rolling axis X direction; referring to fig. 23, 90 ° is a state in which the rotation axis of the tiltrotor is oriented upward in the vertical direction, and referring to fig. 22, the rotation axis of the tiltrotor is inclined between 0 ° and 90 °. When the tilting angle is 90-110 degrees, the vertical take-off and landing aircraft can realize forward and backward flight of the aircraft nose, so that the flight envelope and capacity of the vertical take-off and landing aircraft are greatly expanded, and the risk that the vertical take-off and landing aircraft needs to turn around in the air is reduced. When the vertical take-off and landing aircraft needs take-off, according to the flight control requirement, all tilt angles of the tilt rotors on the inner side can be set at any angle of 0-90 degrees, for example, can be set at 0 degrees, 30 degrees, 45 degrees, 60 degrees or 90 degrees, etc.

The number of the tilting rotors on the tail wing 30 may be any even number less than 2N, preferably, referring to fig. 5 to 9, in this embodiment, the vertical takeoff and landing aircraft includes four tilting rotors and four fixed rotors, four of the fixed rotors are symmetrically installed on two sides of the fuselage 10, four of the tilting rotors are located on the spanwise inner sides of four of the fixed rotors, two of the tilting rotors are installed on the tail wing 30, and two of the tilting rotors are installed on the fuselage 10 or the wing 20 on the front side of the wing 20. Specifically, the four tiltrotors are divided into two equal sets, labeled as a first set of tiltrotors mounted on the fuselage 10 or wing 20 on the front side of the vertical takeoff and landing aircraft center of gravity G, and a second set of tiltrotors mounted on the tail wing 30 on the rear side of the vertical takeoff and landing aircraft center of gravity G, respectively. The first set of tilt rotors includes a first tilt rotor 41 and a second tilt rotor 42, and the second set of tilt rotors includes a third tilt rotor 43 and a fourth tilt rotor 44. First tiltrotor 41 is mounted on third horn 411, and second tiltrotor 42 is mounted on fourth horn 421 and is symmetrical to first tiltrotor 41 about plane of symmetry 60 of fuselage 10. Third tiltrotor 43 is mounted to tail 30 via a first nacelle 442 and fourth tiltrotor 44 is mounted to tail 30 via a second nacelle 442. The first power pod 442 and the second power pod 442 are symmetrically disposed about the plane of symmetry 60 of the fuselage 10 and the fourth tiltrotor 44 and the third tiltrotor 43 are symmetrically disposed about the plane of symmetry 60 of the fuselage 10.

In the vertical take-off and landing state, the rotation shafts of the four tilting rotors tilt upward in the vertical direction, and the first tilting rotor 41, the second tilting rotor 42, the third tilting rotor 43 and the fourth tilting rotor 44 are all distributed on a first circumference centered on the point B. The projections of the first tilt rotor 41 and the fourth tilt rotor 44 on the horizontal plane are centered with respect to the point B, and the projections of the second tilt rotor 42 and the third tilt rotor 43 on the horizontal plane are centered with respect to the point B.

Referring to fig. 7, the four fixed rotors are divided into two equal numbers of fixed rotors, respectively designated as a first fixed rotor and a second fixed rotor, the first fixed rotor is mounted on the front wing 20 of the center of gravity of the vertical takeoff and landing aircraft, and the second fixed rotor is mounted on the rear wing 20 of the center of gravity of the vertical takeoff and landing aircraft. The first fixed rotor wings are composed of a first fixed rotor wing 51 and a second fixed rotor wing 52, the second fixed rotor wings are composed of a third fixed rotor wing 53 and a fourth fixed rotor wing 54, and the first fixed rotor wings 51, the second fixed rotor wings 52, the third fixed rotor wings 53 and the fourth fixed rotor wings 54 are distributed on a second circumference taking the point A as the center. The first fixed rotor 51 and the second fixed rotor 52 are symmetrical about the symmetry plane 60 of the fuselage 10, the third fixed rotor 53 and the fourth fixed rotor 54 are symmetrical about the symmetry plane 60 of the fuselage 10, the rotation axes of the four fixed rotors all extend upwards, the projections of the first fixed rotor 51 and the fourth fixed rotor 54 on the horizontal plane are central symmetrical about the point a, and the projections of the second fixed rotor 52 and the third fixed rotor 53 on the horizontal plane are central symmetrical about the point a. In the present application, the front side means the extending direction toward the nose, and the rear side means the extending direction toward the tail 30.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, the pitch of four of the fixed rotors along the direction of extension of the fuselage, i.e., the pitch of the second fixed rotor 52 to the fourth fixed rotor 54, or the pitch of the first fixed rotor 51 to the third fixed rotor 53 is L3. The pitch of the four tiltrotors along the extending direction of the fuselage, that is, the pitches of the second tiltrotor 42 to the fourth tiltrotor 44, or the pitches of the first tiltrotor 41 to the third tiltrotor 43 are L4, is 0.1 (l3+l4) > 4l1+2l2 > 0.01 (l3+l4). The arrangement mode can enable the gravity center G point to be close to the front side relative to the point A and the point B in the tilting stage and the cruising stage, the point B is always located on one side, close to the tail wing 30, of the point A, the longitudinal and course static stability margin is relatively large, the capability of the airplane for resisting extremely high wind weather is stronger, and the flying is safer.

Referring to fig. 7, a first arm 511 is mounted on the wing 20 on one side of the fuselage 10, and a second arm 521 is mounted on the wing 20 on the other side of the fuselage 10; the first horn 511 and the second horn 521 are symmetrically arranged about the symmetry plane 60 of the fuselage 10, and the 2M fixed rotors are symmetrically mounted on the first horn 511 and the second horn 521 at two sides of the fuselage 10, respectively, and are located at front and rear sides of the wing 20 and front and rear ends of the first horn 511 and the second horn 521, respectively, and at the same time, all projections of the fixed rotors on the horizontal plane are approximately symmetrical about the point a in a pair-wise correspondence.

Referring to fig. 1 to 4, in an embodiment, unlike the vertical takeoff and landing aircraft of fig. 5 to 9, the vertical takeoff and landing aircraft of this embodiment includes only four tilting rotors without fixed rotors, four tilting rotors are symmetrically installed on both sides of the fuselage 10, two of the tilting rotors are symmetrically installed on the wing 20 with respect to the fuselage 10, and the structure and installation relationship of the four tilting rotors with respect to the fuselage are the same as those of fig. 5 to 9 and fig. 34, and specific positions are adaptively adjusted according to the aircraft, which will not be repeated herein.

Unlike the vertical takeoff and landing aircraft of fig. 1 to 4, in another embodiment of the vertical takeoff and landing aircraft of the present invention, the vertical takeoff and landing aircraft includes six tiltrotors, instead of fixed rotors, symmetrically mounted on both sides of the fuselage 10, wherein four of the tiltrotors are symmetrically mounted on the wing 20 with respect to the fuselage 10, and the other two of the tiltrotors are symmetrically mounted on the tail 30. The fin 30 is a V-shaped fin, two of the tilt rotors on the fin 30 are full tilt rotors, two of the full tilt rotors are respectively mounted on two wing tips on the upper portion of the V-shaped fin, the two tilt rotors are respectively mounted on wing tips of the wings 20 on two sides of the fuselage 10 and are symmetrical with respect to a symmetry plane 60 of the fuselage 10, the tilt rotors on the wing tips of the wings 20 are preferably full tilt rotors, and finally the remaining two tilt rotors are mounted on the front side of the wings 20 through the horn to be partial tilt rotors. However, the tiltrotor mounted on the front side of wing 20 via the horn may be a full tiltrotor, if the conditions allow.

In the present invention, the elevator 31 may be mounted at any suitable position on the tail wing 30, or may be mounted at any suitable elevator 31. Specifically, referring to fig. 5 and 17, the elevator 31 includes a rudder plate 311 and a rudder body driving device (not shown), wherein the rudder plate 311 is rotatably connected to the tail wing 30 or the tail of the fuselage 10, and the rudder body driving device drives the rudder plate 311 to rotate to adjust the direction of the vertical takeoff and landing aircraft. The elevator 31 drive includes, but is not limited to, a motor, or a combination of a motor and a speed reducer.

Referring to fig. 25, in some embodiments, the ratio of the chord length of the rudder plate 311 to the chord length of the tail wing 30 is 15% -100%, for example, may be any value between 15%, 30%, 45%, 60%, 90%, 100%, etc. 15% -100%, and as an example, as shown in fig. 18, the chord length of the rudder plate 311 is 30% of the chord length of the tail wing 30; as shown in fig. 19, the chord length of the rudder plate 311 is 60% of the chord length of the tail wing 30; as shown in fig. 20, the chord length of the rudder plate 311 is 100% of the chord length of the tail wing 30, but is not limited to the ratio of fig. 18 to 20. Note that, referring to fig. 25, the chord length is the distance from the front edge point to the rear edge point of the section of the airfoil of the tail wing 30, and the chord length ratio is the ratio of the length of the rudder plate on the tail wing 30 in the direction of the flight to the length of the tail wing 30 (not the length ratio in the direction of the span Y) in the plan view.

Referring to fig. 18, in an embodiment of the vertical takeoff and landing aircraft according to the present invention, the rudder plate 311 is deflected by an angle of-90 ° to 30 ° based on the rolling axis X and in the forward direction, for example, as shown in fig. 23, the rudder plate 311 may be deflected by any angle between-90 ° and-30 ° such as-90 °, -60 °, -30 °, -15 °, 0 °, 15 ° and 30 °.

In an embodiment of the vertical take-off and landing aircraft of the present invention, as shown in fig. 9, 2N of the rotation axes of the 2N tilt rotors and 2M of the fixed rotors may be disposed along the vertical direction, and preferably, in an embodiment of the vertical take-off and landing aircraft of the present invention, 2N of the tilt rotors are symmetrically disposed on two sides of the fuselage 10, and an angle α between a plane formed by the rotation axes of the rotors (i.e., a plane formed by the rotation axes of the rotors rotating around the tilt axis center) and a plane 60 of the fuselage 10 during the tilting process is between-15 ° and +15°, for example, any angle between-15 °, -10 °, 0 °, 10 °, 15 ° and 15 ° may be between-15 ° and +15°, and may be positive in a direction from bottom to top, and slant from bottom to top to the plane 60 of symmetry. The angle between the rotation axes of the 2M fixed rotor wings and the plane of symmetry of the fuselage is-15 ° to +15°, for example, any angle between-15 °, -10 °, 0 °, 10 °, 15 ° and the like-15 ° to +15°, and the angle is positive with the direction from bottom to top and the angle is negative with the direction from bottom to top toward the plane of symmetry 60.

In the present invention, the tail wing 30 may be any one of a V-type tail wing, a Y-type tail wing, an H-type tail wing, an X-type tail wing, a T-type tail wing, an H-type tail wing, or a U-type tail wing, and the tilt rotor on the tail wing 30 is mounted on the upper side of the tail wing 30 and is tilted upward in a vertical take-off and landing state. This reduces the likelihood of injury to the occupant as the occupant enters and exits the aircraft. Referring to fig. 1 to 4, in the present embodiment, the tail wing 30 is a V-shaped tail wing, two tilt rotors are mounted on the tail wing 30, and the two tilt rotors are respectively mounted on two wing tips on the upper portion of the tail wing 30. The flight 30 may be any of the shapes described above in other embodiments.

In this embodiment, when the vertical takeoff and landing aircraft flies forward and is in a cruising state, the rotation axis of the tilt rotor on the tail wing 30 and the rotation axis of the tilt rotor at other positions may extend along the rolling axis X, but in other embodiments, the rotation axis of the tilt rotor on the tail wing 30 and the rotation axis of the tilt rotor at other positions may not extend along the rolling axis X, and may be within a range of ±20° based on the rolling axis X in a vertical plane where the rolling axis X is located. In addition, in the present invention, the control of the power pods 442 of the tilting rotors projected along the direction of the rolling axis X at different coordinate positions of the rolling axis X may be independent of each other, and the tilting may be controlled independently of each other, in which mode, the tilting angles of the tilting rotors on the front side and the tilting rotors on the tail wing 30 may be inconsistent, the tilting process may be asynchronous, for example, the tilting angle of the power pods 442 of the tilting rotors on the front side fuselage 10 or the wing 20 may be 10 ° and the tilting angle of the power pods 442 of the tilting rotors on the rear side fuselage 10 or the wing 20 may be-10 ° with the rolling axis X being positive above the rolling axis X and negative below the rolling axis X.

It should be noted that, when the vertical takeoff and landing aircraft of the present invention is in the vertical takeoff and landing state, the rotation axis of the tiltrotor on the tail wing 30 and the rotation axis of the tiltrotor at other positions may or may not extend upward in the vertical direction. That is, the tilt angles of the front tilt rotor and the tilt rotor on the tail 30 are not limited to being set at the tilt angle of 90 °, and the tilt angle of the rotation axis of the front tilt rotor and the tilt angle of the rotation axis of the tilt rotor on the tail 30 may be any value between 70 ° and 110 °, for example, 70 °, 80 °, 90 °, 100 °, 110 °, and the like, for the purpose of enhancing the control capability. The rotational control and the tilt control of each of the 2N tilt rotors are relatively independent, and the tilt angles of the 2N tilt rotors may be set to be identical, may be set to be different between any two, may be set to be partially identical, and, for example, may be set to be identical between the tilt angles of the 2N tilt rotors located on the fuselage 10 or wing 20 on the front side of the tail wing 30, may be labeled as a first tilt angle, and the tilt angles of the tilt rotors on the rear side tail wing 30 may be set to be identical, may be labeled as a second tilt angle, and may be set such that the first tilt angle is not equal to the second tilt angle, for example, the first tilt angle may be 100 °, and the second tilt angle may be 80 °. This allows different pitch trim moments to be obtained at different positions. The tilt angle is an angle between the rotation axis of the tilt rotor and the roll axis X with the center point of the tilt axis of the tilt rotor as the vertex.

Referring to fig. 7 and fig. 28 to 32, the present invention provides a control method of a vertical takeoff and landing aircraft, wherein the vertical takeoff and landing aircraft includes: fuselage and 2N rotor that tilt. The fuselage 10 is of symmetrical construction and has a plane of symmetry 60 extending along the length of the fuselage 10. Wings 20 are arranged on two sides of the fuselage 10, and the wings 20 on two sides are symmetrical relative to a symmetrical plane 60 of the fuselage 10. The tail of the fuselage 10 is provided with a tail wing 30, and the tail wing 30 is provided with an elevator 31.2N tiltrotors are mounted on both sides of the fuselage 10, N is a natural number greater than or equal to 2, 2N tiltrotors are symmetrically disposed about a plane of symmetry 60 of the fuselage 10, and a portion of 2N tiltrotors are mounted on the tail wing 30. And when the vertical take-off and landing aircraft is in a cruise state transition from the vertical take-off and landing state, the point G and the point B move along the symmetry plane towards the side close to the nose, and the point B is always positioned at the side close to the tail wing.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, pitch control is performed using the following method:

during the flying process, distributing the pitch control proportion of the elevator 31 to 2N tilt rotors and 2M fixed rotors according to the current airspeed or dynamic pressure; according to the pitch control ratio, the elevators 31, 2N of the tiltrotors, and 2M of the fixed rotors are controlled respectively to achieve pitch balancing and manipulation.

In one embodiment of the vertical takeoff and landing aircraft of the present invention, controlling 2N of said tiltrotors according to said pitch control ratio includes: the tilting angle differential adjustment process comprises the following steps: i.e. by the tilt angle difference between said tilting rotor on the tail 30 and any other said tilting rotor on the front side of the tail, the pitching moment is differentially adjusted for pitch balancing and steering. And/or rotational speed differential adjustment process: namely, the pitching moment is differentially regulated to pitch balancing and manipulation by the rotation speed difference of the tilting rotor on the tail wing 30 and any other tilting rotor on the front side of the tail wing; and/or, a tilting speed differential adjustment process: namely, the pitching moment is differentially regulated to perform pitching trimming and manipulation through the tilting speed difference between the tilting rotor on the tail wing and any other tilting rotor on the front side of the tail wing. It should be noted that the above-mentioned tilting angle differential adjustment process, rotation speed differential adjustment process, tilting speed differential adjustment process may be implemented individually or in combination with each other, or may be implemented in three embodiments at the same time.

Referring to fig. 28, the flight process sequentially includes four stages, specifically: s100, a ground preparation process, S200, a take-off control process, S300, a take-off turning-to-flat flight control process, S400 and a cruise state.

S100, a ground preparation process. The ground preparation process firstly needs to start the vertical take-off and landing aircraft, and electrifies and detects the system, and then confirms the full stroke state of the tilting mechanism, the elevator 31 and other servo systems.

S200, taking off control process. The take-off control process is a process that the vertical take-off and landing aircraft climbs to a set height from the ground, and in the process, the tilting rotor and the fixed rotor keep the tilting angle and the rotating speed unchanged, and the process is relatively stable relative to the leveling process.

S300, taking off and turning to the flat flight control process. The control process of taking off and leveling is mainly involved in the change of the tilting angle of the tilting rotor wing and/or the change of the rotating speed of the tilting rotor wing and/or the fixed rotor wing, so that the pitching impact force applied in the process is large, and the control of the vertical take-off and landing aircraft is relatively difficult.

S400, cruising state. In the cruising state, the vertical take-off and landing aircraft flies horizontally, and the aircraft sails along the horizontal direction relatively stably.

Referring to fig. 32, in one embodiment, the takeoff control process of step S200 includes the following steps:

s211, tilting 2N tilting rotors to a vertical lifting position or a tilting position (for example, between 0 and 90 degrees) with the rotation axis vertically upwards so as to power climbing. The vertical take-off and landing position can be a position where the rotation axis of the tilting rotor forms an included angle of 90 degrees with the rolling shaft; the tilt position may be a position between 0 deg. and 90 deg. (excluding the end point value) between the rotation axis of the tilt rotor and the roll axis;

s212, deflecting the elevator 31 downwards, so that the elevator 31 participates in take-off control;

s213, starting 2N tilting rotors, and sending out a plane flight instruction when the vertical take-off and landing aircraft reaches a set altitude.

In the take-off process of S211 to S213, if the tiltrotors are placed at 90 °, the vertical take-off and landing aircraft will take off normally, and 2N tiltrotor throttles will be consistent. At this time, the tilt rotor wing of the tail wing 30 has the largest shielding area in the vertical stage and the transition stage, and can induce a larger head-up moment. If the rotation axes of all the tilting rotors are placed at the inclined positions between 0 and 90 degrees, the inner tilting rotor starts an accelerator when the aircraft takes off, and the aircraft climbs upwards due to forward tension components provided by the inner tilting rotor, when the flying speed is gradually increased, the tilting angle of the inner tilting rotor is gradually reduced until the aircraft tilts to a 0-degree flat flying fixed wing mode. According to the scheme, the aircraft has moderate head-up moment caused by the fact that the tail wing 30 shields the tilting rotor, the control difficulty is small, and the requirement on the maximum tension allowance of the power system is small.

As an optimization, referring to fig. 29, the take-off and fly-leveling control process in S300 in this embodiment includes the following steps:

s310, responding to the fly-flat instruction. The plane flight instruction can be issued by a pilot or by the vertical take-off and landing aircraft when judging that the preset flight condition is met.

S320, a rotor wing control process. The process is greatly affected by the takeoff control process of S200, and may vary greatly depending on the state of the tiltrotor.

S330, a pitching control process. Considering that the tilting rotor is tilted to the set cruising position with the rotation axis of the tilting rotor parallel to the rolling shaft for multiple times in the process of taking off and leveling, the vertical take-off and landing aircraft can receive a certain pitching impact force in the process of tilting each time, and the pitching control process of S330 can be carried out after each S320 rotor control process of taking off and leveling.

And S340, repeatedly executing the rotor wing control process and the pitching control process in sequence until the tilting rotor wing tilts to the cruising position, and completing taking off and turning flat flight. The cruising position may be, for example, a position where the rotation axis of the tilt rotor is parallel to the rolling axis when the tilt angle is 0 °.

Referring to fig. 31, in one embodiment, the rotor control process in step S320 includes the following steps:

S321, acquiring the current tilting position of each tilting rotor; the process can set an angle sensor on the tilting rotor so as to feed back the current tilting position to the central control system, and can also feed back the corresponding current tilting position to the central control system directly through a tilting driving device corresponding to the tilting rotor.

S322, if the current tilting position is inconsistent with the set cruising position, acquiring the current airspeed or dynamic pressure of the corresponding tilting rotor wing at the current tilting position, and judging whether the current airspeed or dynamic pressure is equal to or greater than a preset threshold value at the current tilting position; the set cruising position is a position where the preset vertical take-off and landing aircraft is in a flat flight state, and may be, for example, a 0 ° position where the rotation axis of the tiltrotor is parallel to the roll axis X, or may be another position between 0 ° ± 5 °.

S323, if the current airspeed or dynamic pressure is equal to or greater than a preset threshold value at the current tilting position, controlling the tilting rotor to tilt to a preset next position;

s324, gradually increasing the rotating speed of 2N tilting rotors. If the vertical take-off and landing aircraft does not have 2M fixed rotors, as shown in fig. 1, the forward power can be obtained by gradually increasing the rotational speed of the 2N tiltrotors. However, as shown in fig. 7, if the vertical take-off and landing aircraft has 2N tiltrotors and 2M fixed rotors, in order to achieve a flat flight, it is necessary to gradually increase the rotational speeds of the 2N tiltrotors and gradually decrease the rotational speeds of the 2M fixed rotors to the set rotational speeds.

Referring to fig. 7, in another embodiment, the vertical takeoff and landing aircraft includes 2M fixed rotors, where M is a natural number greater than or equal to 2, and M may be the same as or different from N. 2M fixed rotors are symmetrically arranged on the wings on two sides of the fuselage and are positioned on the outer sides of the tilting rotors; in the vertical take-off and landing state, the projection of all the fixed rotors on the horizontal plane is centrosymmetric about the point A, wherein the point A is positioned in the symmetrical plane of the fuselage and coincides with the point G or is positioned on one side of the point G, which is close to the tail wing. In the process of transition of the vertical take-off and landing aircraft from the vertical take-off and landing state to the cruise state, the point G and the point B move along the symmetrical surface towards one side close to the nose, the point G is positioned at one side close to the nose of the point A or coincides with the point A, and the point B is always positioned at one side close to the tail wing of the point A. Referring to fig. 33, in an embodiment, the take-off process of the vertical takeoff and landing aircraft in S200 is different from the processes of S211 to S213 in fig. 32, and the take-off process of S200 includes:

s221, tilting 2N tilting rotors to the front direction of the rotation axis horizontally and parallel to the rolling axis X;

s222, deflecting the elevator 31 downwards;

S223, starting 2M fixed rotors and 2N tilting rotors, and sending out a plane flight instruction when the vertical take-off and landing aircraft reaches a set height.

In the take-off process in S221 to S223, the rotation axes of all the tilting rotors are set at 0 ° (as shown in fig. 7), the aircraft is changed into a compound wing mode, the aircraft is taken off vertically by the outer multiple rotors, the output of the outer multiple rotors is twice as high as that of the first control scheme, the inner tilting rotors are gradually started in the vertical tilting transition stage, the throttle is gradually increased until the tilting is successful, the shielding area of the rear wing 30 of the inner tilting rotor is minimum, the head-lifting moment is minimum, the control is simplest, and the control mode is basically the compound wing control mode, but the required tension margin of the power system is larger, the requirement on the power system is higher, and the control mode is reduced in a non-emergency condition.

As will be appreciated by those skilled in the art, since the axis of the tiltrotor is always parallel to the roll axis X during take-off in S221 to S223, the relevant process of S321 to S323 is no longer required during the S320 rotor control in the S300 take-off and level flight control, and only the rotational speeds of 2N tiltrotors need to be increased gradually and the rotational speeds of 2M fixed rotors need to be reduced gradually to the set rotational speeds.

It should be noted that, whether the rotor control process in S300 has the tilting control process in S321 to S324, the vertical take-off and landing aircraft receives a high pitch impact force during the process of taking off and landing, and therefore, referring to fig. 30, in an embodiment of the present invention, the pitch control process in step S330 includes:

and S332, distributing the pitching control proportion of the elevator 31, 2N tilting rotors and 2M fixed rotors according to the current airspeed or dynamic pressure. In the process, according to the current speed of the current vertical take-off and landing aircraft, the pitching adjusting force is distributed to the elevator 31, 2N tilting rotors and 2M fixed rotors according to a set distribution rule, so that balanced pitching control is achieved through pitching control proportion.

S333, respectively controlling the elevator, the 2N tilting rotors and the 2M fixed rotors according to the pitching control proportion so as to realize pitching balancing and operation. In this process, the central control system controls the elevator 31, 2N of the tiltrotors and 2M of the fixed rotors according to the allocated pitch control proportion, for example, may be rotational speed differential control, deflection of the elevator 31, and the like, so that different pitch adjusting forces are generated at different positions of the vertical take-off and landing aircraft, so as to balance with the pitch impact force in the process of flying in a plane.

In an embodiment, the vertical take-off and landing aircraft of the present invention has 2N tilt rotors disposed on the inner sides of 2M fixed rotors, and the elevator 31 and the full-tilt rotor are disposed on the tail wing 30, so that the pitch impact force in the roll-off process can be balanced through the pitch control process, and on one hand, a more stable control process can be obtained. On the other hand, in the pitch control process, the power nacelle 442 rotates along with the rotor in the tilting process of the tail wing 30, and the shielding area of the power nacelle 442 in the corresponding rotor is smaller when hovering, so that the area of the rotor down-wash on the tail wing 30 is smaller, a part of head-up moment can be reduced, and the control of the pitch moment of the vertical take-off and landing aircraft under a complex disturbance flow field can be improved.

If the vertical take-off and landing aircraft does not include 2M fixed rotors, in step S332, the fixed rotors do not need to be considered, and the pitch control ratios of the elevator 31 and 2N of the tiltrotors need to be distributed according to the current airspeed or dynamic pressure. And correspondingly, in step S333, the fixed rotor is not required to be considered, and only the elevator and 2N tilt rotors are required to be controlled respectively according to the pitch control proportion, so as to realize pitch balancing and manipulation.

In consideration of the fact that the elevator 31 is involved in the control process during the take-off of the vertical take-off and landing aircraft, the pitch control process according to the present invention further includes, before step S332: and step S331, controlling the elevator 31 to return to zero or to be actuated to a trimming rudder deflection value matched with the current airspeed or dynamic pressure in time according to the current airspeed or dynamic pressure, and gradually participating in the pitch control process. For example, an airspeed threshold may be set and elevator 31 is zeroed back to its initial position without deflection when the current airspeed is greater than or equal to the set airspeed threshold, at which point the rudder deflection angle is 0 °.

In this embodiment, according to the pitch control ratio, controlling the elevator and the 2N tilt rotors respectively to implement pitch balancing and manipulation includes: the pitching moment is differentially adjusted for pitch balancing and steering by the difference in tilting speed and/or tilting angle between the tilting rotors and/or the difference in rotational speed of the tilting rotors at different positions.

Referring to fig. 27, fig. 27 is a graph of full plane pitching moment generated by comparing the partial pitch scheme of the nacelle of the rotor tilting on the tail wing 30 with the full pitch scheme of the nacelle of the rotor tilting on the tail wing 30 through aerodynamic simulation analysis. The first curve 101 is a simulation curve of the simulation model in fig. 7, and the structure of the tilting rotor at the tail part of the simulation model is referred to fig. 20 during pneumatic simulation analysis, the second curve 102 is a partial tilting model, which is different from the vertical take-off and landing aircraft model in fig. 7 only in the structure of the tilting rotor on the tail wing 30, and is the same as the rest except for the scheme of partial tilting of the power nacelle. In the simulation analysis in the two models, the rotational speeds of the four fixed rotors and the four tilting rotors are equal and the pulling force matches the aircraft takeoff weight (pulling force versus gravity trim state).

In fig. 27, a first curve 101 and a second curve 102 are respectively curves of change of pitching moment of two full-plane models along with flying speed (i.e. wind speed), in which flying speed is subjected to dimensionless treatment, and a process of 0-1 is that the aircraft flies from a hovering state to a maximum speed under a current tilting angle (the 90-degree tilting angle is kept unchanged), namely, flies from a minimum speed to the maximum speed under the current tilting angle; the pitching moment in the figure is also dimensionless.

As can be seen from a comparison between the first curve 101 and the second curve 102 in fig. 27, when 8 rotors have no front-rear accelerator differential motion, the aircraft generates a larger pitching moment, so that when the aircraft is required to fly smoothly, the pitching moment needs to be trimmed, and the pitching angular acceleration is 0, and when the aerodynamic pitching moment is trimmed, the front-rear rotor accelerator differential motion is required, so that the pitching moment generated by the rotor differential motion and the aerodynamic pitching moment generated by the aircraft body are offset. The pod full pitch scheme control method requires 0.25 units for maximum pitch trim and maneuvers generated during flight. The control method of the partial tilting scheme of the power nacelle 442 needs 0.8 unit for the maximum pitching trimming and operation of the whole aircraft, which is greatly larger than that of the full tilting control method, the larger the pitching moment generated in the flight process is, the more difficult the aircraft is to control, and the larger the additional power for adjusting the attitude of the aircraft is needed by the power system. In addition, as can be seen from the simulation curve shown in fig. 27, as the flying speed is greater, the pitch balancing and manipulation demand fluctuation generated by the control method of the partial tilting scheme of the power nacelle 442 is also greater, the change from-0.04 in a hovering state (the dimensionless wind speed is 0) to about 0.8 (the dimensionless wind speed is 0.57), the fluctuation of the pitch moment is very severe, and the control method is very unfavorable for the pitch control of the aircraft; the pitching moment generated by the full-tilting scheme control method of the anti-observation power nacelle 442 is changed from minus 0.25 in a hovering state (the dimensionless wind speed is 0.42) to about 0.25, the pitching moment fluctuation is small, and the control of the pitching direction of the aircraft is facilitated, so that the vertical take-off and landing aircraft and the pitching control method provided by the invention are simple and effective, and the safety of the aircraft can be effectively improved.

In summary, the vertical take-off and landing aircraft is provided with the elevators and the 2N tilting rotors, in the vertical take-off and landing state, the projections of the propellers of the 2N tilting rotors on the horizontal plane are centrosymmetric about a point B, the point B and a gravity center G point of the vertical take-off and landing aircraft are both positioned in a symmetrical plane of the fuselage, and the point B is positioned on one side of the point G close to the tail wing. And in the process of transition of the vertical take-off and landing aircraft from the vertical take-off and landing state to the cruising state, the point B is always positioned at one side of the point G, which is close to the tail wing. With this arrangement, the center of gravity G of the vertical takeoff and landing aircraft and the center of symmetry B of the tiltrotor are not coincident, and both the G and B points move along the symmetry plane toward the nose side during transition of the vertical takeoff and landing aircraft from the vertical takeoff and landing state to the cruise state. Therefore, the traction force generated by the front-gravity-center tilt rotor wing is smaller to the moment of the gravity center G point, the traction force generated by the rear-gravity-center tilt rotor wing is larger to the moment of the gravity center G point, and the moment difference of the front-and-back tilt rotor wings can resist the partial head-up moment generated by the action of the tail wing tilt rotor wing upwash zone on the tail wing, so that the difficulty of pitching operation can be reduced. Therefore, under the condition that the rotating speeds of the tilting rotors are the same at the front side and the rear side of the gravity center G point, because the length difference of the moment arm on the gravity center G point can generate low head moment, the head lifting moment generated by the action of the tilting rotor washing area on the tail wing can be counteracted or partially counteracted by the low head moment, so that the vertical take-off and landing aircraft can better balance the pitching moment under the condition that the front and rear rotor speeds are consistent.

According to the control method, the elevator and the pitching control proportion of 2N tilting rotors are distributed according to the current airspeed or dynamic pressure, and pitching control can be realized through linkage of the elevator and the 2N tilting rotors. Therefore, the invention effectively overcomes some practical problems in the prior art, thereby having high utilization value and use significance.

Claims

1. A vertical takeoff and landing aircraft, comprising:

the aircraft comprises an aircraft body, wherein wings are arranged on two sides of the aircraft body, a tail fin is arranged at the tail part of the aircraft body, and an elevator is arranged on the tail fin;

2N tilting rotors symmetrically arranged on two sides of the fuselage, and part of 2N tilting rotors is positioned on the tail wing;

and when in a vertical take-off and landing state, the projections of the propellers of the 2N tilting rotors on the horizontal plane are centrally symmetrical about a point B, the point B and the gravity center G of the vertical take-off and landing aircraft are both positioned in the symmetrical plane of the fuselage, the point B is positioned on one side of the point G, which is close to the tail wing, and in the mode change process of the vertical take-off and landing aircraft, the point G and the point B are both moved along the symmetrical plane, and the point B is always positioned on one side of the point G, which is close to the tail wing.

2. The vertical takeoff and landing aircraft according to claim 1, characterized in that,

during flight, the rotation axis of any one of the tiltrotors on the tail wing and the rotation axis of any one of the tiltrotors at other positions are projected non-parallel on the plane of symmetry of the fuselage.

3. The vertical takeoff and landing aircraft according to any of the claims 1 to 2, characterized in that,

in the cruising state and/or the hanging state and/or the mode conversion state, a first difference exists between the tilting speed of any one of the tilting rotors on the tail wing and the tilting speed of any one of the tilting rotors at other positions, and the first difference is not equal to 0.

4. The vertical takeoff and landing aircraft according to any of the claims 1 to 2, characterized in that,

at cruising and/or drooping and/or mode transition, there is a second difference between the rotational speed of any one of the tiltrotors on the tail and the rotational speed of any one of the tiltrotors at other positions, and the second difference is not equal to 0.

5. The vertical-takeoff and landing aircraft of claim 1, wherein said vertical-takeoff and landing aircraft is pitch controlled by:

6. The vertical takeoff and landing aircraft according to claim 5, wherein controlling 2N of said tiltrotors according to said pitch control ratio includes:

7. The vertical takeoff and landing aircraft according to claim 2, characterized in that,

the vertical take-off and landing aircraft comprises four tilting rotors, wherein four tilting rotors are symmetrically arranged on two sides of the fuselage, two tilting rotors are symmetrically arranged on the wing relative to the fuselage, and the other two tilting rotors are symmetrically arranged on the tail wing.

8. The vertical takeoff and landing aircraft according to claim 2, characterized in that,

the vertical take-off and landing aircraft comprises six tilting rotors, wherein six tilting rotors are symmetrically arranged on two sides of the fuselage, four tilting rotors are symmetrically arranged on the wing relative to the fuselage, and the other two tilting rotors are symmetrically arranged on the tail wing.

9. The vertical takeoff and landing aircraft according to claim 7 or 8, wherein said tail is a V-shaped tail, two of said tilt rotors on said tail are full tilt rotors, and two of said full tilt rotors are mounted on the tips of the two sides of the upper portion of said V-shaped tail, respectively.

10. The vtol aerial vehicle of claim 7 or 8, wherein two tiltrotors are provided at the wing tips of the wings, the tiltrotors located on the wing tips of the wings being full tiltrotors.

11. The vtol aerial vehicle of claim 1 further comprising 2M fixed rotors, M being a natural number greater than or equal to 2, the 2M fixed rotors being symmetrically mounted on the wings on either side of the fuselage and outboard of the tiltrotors; and in the vertical take-off and landing state, the projections of all the fixed rotors on the horizontal plane are centrally symmetrical about the point A, the point A is positioned in the symmetrical plane of the fuselage, the point G is positioned on one side of the point A close to the nose or coincides with the point A in the mode change process of the vertical take-off and landing aircraft, and the point B is always positioned on one side of the point A close to the tail wing.

12. The vertical takeoff and landing aircraft according to claim 11, characterized in that the vertical takeoff and landing aircraft is pitch controlled by the following method:

13. The vertical takeoff and landing aircraft according to claim 11, characterized in that,

the vertical take-off and landing aircraft comprises four tilting rotors and four fixed rotors, wherein the four fixed rotors are symmetrically arranged on two sides of the fuselage, the four tilting rotors are positioned on the inner sides of the four fixed rotors, two of the tilting rotors are symmetrically arranged on the tail wing, and the two tilting rotors on the tail wing are all tilting rotors.

14. The vertical takeoff and landing aircraft according to claim 1, characterized in that,

the tail wing is a V-shaped tail wing, two tilting rotors are mounted on the V-shaped tail wing, the two tilting rotors are mounted on wing tips of the V-shaped tail wing respectively, when in a vertical take-off and landing state, the distance between the rotation center of the tilting rotor wing on the tail wing and the front edge of the wing tip of the V-shaped tail wing is t1, the chord length of the wing tip of the V-shaped tail wing is t2, and the ratio of t1 to t2 is 15% -40%.

15. The vertical takeoff and landing aircraft according to claim 1, characterized in that,

the tilting rotor on the tail wing is a full tilting rotor; the tiltrotor located beyond the tail wing is a partial tiltrotor.

16. The vertical takeoff and landing aircraft according to claim 1, characterized in that,

and the wing tip of the wing is provided with a tilting rotor wing, and the tilting rotor wing on the tail wing and the tilting rotor wing on the wing tip of the wing are all tilting rotor wings.

17. The vertical takeoff and landing aircraft according to claim 15 or 16, characterized in that,

the full tilting rotor comprises a first rotor and a power nacelle, wherein the first rotor is connected with the power nacelle, the power nacelle is rotationally connected with the tail wing or the wing, and the power nacelle is synchronously tilted along with the first rotor in the tilting process of the first rotor.

18. The vertical takeoff and landing aircraft according to claim 1, characterized in that,

the rudder comprises a rudder plate and a rudder body driving device, wherein the rudder plate is rotationally connected to the tail of the tail wing or the fuselage, and the rudder body driving device drives the rudder plate to rotate so as to adjust the direction of the vertical take-off and landing aircraft.

19. A method of controlling a vertical takeoff and landing aircraft according to claim 1, characterized by the following pitch control procedures:

20. The control method of claim 19, further comprising the following rotor control procedure prior to assigning pitch control ratios of the elevator to 2N of the tiltrotors based on current airspeed or dynamic pressure:

acquiring the current tilting position of each tilting rotor;

the rotational speed of 2N tilting rotors is gradually increased.

21. The control method according to claim 20, characterized in that the control method further comprises: and (5) sequentially repeating the rotor wing control process and the pitching control process until the tilting rotor wing tilts to the cruising position, and completing taking off and leveling off.

22. The control method according to claim 20, characterized in that,

the vertical take-off and landing aircraft further comprises 2M fixed rotors, wherein M is a natural number greater than or equal to 2; 2M fixed rotors are symmetrically arranged on the wings on two sides of the fuselage and are positioned on the outer sides of the tilting rotors;

in the process of gradually increasing the rotating speed of the 2N tilting rotors, the method further comprises the following steps: the rotational speed of the 2M fixed rotors is gradually reduced to the set rotational speed.

23. The control method of claim 22, further comprising the following takeoff control procedure prior to said rotor control:

deflecting the lifting rudder downwards;

24. The control method according to claim 19, wherein,

Before distributing the pitch control proportion of the elevator to 2N tilting rotors according to the current airspeed or dynamic pressure, the method further comprises the following take-off control process:

tilting 2N of said tiltrotors to an axis of rotation horizontally forward;

deflecting the lifting rudder downwards;

25. The control method of claim 24, further comprising, after the takeoff control process, prior to pitch control, the following rotor control process: the rotating speed of 2N tilting rotors is gradually increased, a forward flight command is sent, and the rotating speed of 2M fixed rotors is gradually reduced to a set rotating speed.

26. A control method according to claim 23 or 25, wherein during the rotor control, after gradually reducing the rotational speed of 2M fixed rotors to a set rotational speed, further comprising controlling the elevator to return to zero according to the current airspeed or dynamic pressure, and gradually participating in the pitch control.

27. The control method according to claim 23 or 25, characterized by further comprising a ground preparation process before the take-off control process, the ground preparation process comprising: and starting the vertical take-off and landing aircraft, powering up and detecting the system, and confirming the full-stroke state of the servo system.

28. The control method according to any one of claims 19 to 25, wherein controlling the elevator, 2N of the tiltrotors, respectively, according to the pitch control ratio to achieve pitch balancing and steering comprises: the pitching moment is differentially adjusted for pitch balancing and steering by the difference in tilting speed and/or tilting angle between the tilting rotors and/or the difference in rotational speed of the tilting rotors at different positions.