Rotor pitch-changing rocker arm size optimization method and unmanned helicopter using the same

Abstract

The invention discloses a method for optimizing the size of a rotor pitch rocker arm and an unmanned helicopter using the method, which is used for a helicopter with a foldable rotor, and comprises: step 1, obtaining the flapping frequency, Locke number and time constant of the rotor based on the flapping hinge extension of the helicopter; step 2, obtaining the taper angle, rear chamfer angle and side chamfer angle of the rotor based on the flapping frequency, Locke number, time constant, lateral control input pitch angle and longitudinal control input pitch angle; step 3, obtaining the pitch control moment and roll control moment of the rotor based on the taper angle, rear chamfer angle and side chamfer angle; step 4, obtaining the longitudinal periodic pitch value and lateral periodic pitch value of the rotor based on the pitch control moment or the roll control moment; step 5, reversely obtaining the phase angle of the pitch rocker arm through the longitudinal periodic pitch value and the lateral periodic pitch value, so as to obtain the pitch control moment or roll control moment corresponding to different phase angles of the pitch rocker arm.

Description

Technical Field

[0001] The invention relates to the field of coaxial twin-rotor helicopters, in particular to a method for optimizing the size of a rotor pitch-changing rocker arm and an unmanned helicopter using the method. Background Art

[0002] Compared with conventional single-rotor unmanned helicopters with tail rotors or multi-rotor unmanned helicopters, coaxial twin-rotor unmanned helicopters can obtain higher lift with the same appearance or rotor size, so they can be designed to be more compact and portable. Therefore, they are becoming increasingly important in aerial photography, military reconnaissance and other fields.

[0003] The flapping hinges of existing articulated unmanned helicopter rotors have a certain amount of overhang, especially for coaxial twin-rotor unmanned helicopters, where the flapping hinges have a larger overhang to meet the folding function. The existence of overhang affects the flapping characteristics of the rotor, resulting in a higher flapping frequency and a flapping response lag angle that is significantly smaller than the theoretical value (close to 90°) when the overhang is zero. Existing coaxial twin-rotor drones are usually designed with a lag angle of 90°, which makes the control torque of the drone seriously too small, resulting in poor wind resistance and slow control response. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for optimizing the size of a rotor pitch rocker arm, which can increase the control torque of a drone to 1.5 to 2 times of the original, making the drone control response faster, more resistant to wind disturbance, and safer in flight.

[0005] An unmanned helicopter made based on the above method is also proposed;

[0006] The technical solution adopted by the first embodiment of the present invention is: a method for optimizing the size of a rotor pitch rocker arm for a helicopter with a foldable rotor, comprising: step 1, based on the flapping hinge extension of the helicopter , get the flapping frequency of the rotor , Locke number , time constant ; Step 2, based on the waving frequency , the Locke number , the time constant , lateral control input pitch angle and longitudinal control input pitch angle , get the taper angle of the rotor , Back chamfer and side chamfer ; Step 3, based on the taper angle , the rear chamfer and the side chamfer , get the pitch control torque of the rotor and roll control torque ; Step 4, based on the pitch control moment or the roll control moment , obtain the longitudinal cyclic pitch value and the lateral cyclic pitch value of the rotor; step 5, reversely obtain the phase angle of the pitch rocker arm through the longitudinal cyclic pitch value and the lateral cyclic pitch value , to obtain different phase angles of the variable pitch rocker arm Corresponding pitch control torque or the roll control moment .

[0007] The rotor pitch rocker arm size optimization method according to the first embodiment of the present invention has at least the following beneficial effects: different phase angles of the pitch rocker arm are obtained by calculation. Corresponding pitch control torque or roll control torque , with pitch control moment For example, when different phase angles are obtained Corresponding pitch control torque Then, the pitch control moment can be selected The UAV is designed with the phase angle corresponding to the maximum torque, so that the pitch control torque of the UAV at this time It will be larger than conventional designs and can be increased to 1.5 to 2 times of conventional designs, making the drone control response faster, more resistant to wind disturbances, and safer to fly.

[0008] According to some embodiments of the present invention, in step 1, the waving frequency The calculation formula is as follows:

[0009]

[0010] Where P is the flapping frequency ratio, is the elastic coefficient of the flapping hinge, is the swing hinge extension, is the swing hinge mass moment, is the swing hinge moment of inertia, is the rotation speed of the rotor;

[0011] The Locke number The calculation formula is as follows:

[0012]

[0013] in, is the air density, is the lift line slope coefficient of the blade airfoil, is the average aerodynamic chord length of the blade.

[0014] The time constant The calculation formula is as follows:

[0015]

[0016] in, is the rotor speed, is the Locke number.

[0017] According to some embodiments of the present invention, in step 2, the taper angle of the rotor is obtained by using the first-order flapping dynamics equations. , Back chamfer and side chamfer , the specific equation is as follows:

[0018]

[0019] in, is the total moment angle, g is the gravity acceleration value, Δ is the correction coefficient of the rotor rotation direction, right rotation is 1, left rotation is -1, is the dynamic coupling ratio, To manipulate the coupling ratio, is the pitch angular velocity, is the rolling angular velocity.

[0020] According to some embodiments of the present invention, in step 2, the dynamic coupling rate and manipulate the coupling ratio Calculated by the following formula:

[0021] .

[0022] According to some embodiments of the present invention, in step 3, the pitch control torque of the rotor is obtained by using the aerodynamic torque calculation equation. and roll control torque , the specific equation is as follows:

[0023]

[0024] in, is the number of blades, is the dimensionless quantity of flapping hinge extension, and R is the rotor radius.

[0025] According to some embodiments of the present invention, in step 5, the phase angle The lateral control input pitch angle , the longitudinal control input pitch angle Through the following relationship:

[0026] .

[0027] The technical solution adopted by the second embodiment of the present invention is: an unmanned helicopter, comprising: the phase angle of the variable pitch rocker arm The rotor pitch rocker arm size optimization method is determined according to the first aspect of the present invention.

[0028] According to some embodiments of the present invention, the invention comprises a fuselage; an upper rotor and a lower rotor arranged coaxially, wherein the upper rotor and the lower rotor are arranged on the top of the fuselage, the upper rotor comprises no less than two upper rotor rotation units, and the lower rotor comprises no less than two lower rotor rotation units;

[0029] The upper rotor rotation unit includes an upper blade 450; an upper swing hinge 440, on which the upper blade 450 is mounted; an upper flap hinge 430, on which the upper flap hinge 430 extends. The upper swing hinge 440 is mounted on the upper swing hinge 430, and the upper blade 450 rotates downward around the upper swing hinge 430 to fit the fuselage through the upper swing hinge 440;

[0030] The lower rotor rotation unit includes a lower blade; a lower swing hinge, on which the lower blade is mounted; a lower flap hinge, on which the lower flap hinge extends The radius of the UAV fuselage is not less than that of the UAV fuselage. The lower swing hinge is installed on the lower flap hinge, and the lower blade is rotated downward around the lower flap hinge through the lower swing hinge to fit the fuselage.

[0031] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0033] Figure 1 This is a flow chart of a method for optimizing rotor pitch rocker arm size according to an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of a foldable coaxial bi-wing UAV rotor in an unfolded state according to an embodiment of the present invention;

[0035] Figure 3 A schematic diagram of a foldable coaxial biplane drone rotor in a folded state according to an embodiment of the present invention;

[0036] Figure 4This is an exploded schematic diagram of the rotor of a foldable coaxial bi-wing UAV according to an embodiment of the present invention;

[0037] Figure 5 Detailed schematic diagram of the variable pitch hinge assembly of the upper rotor of the foldable coaxial biplane UAV according to an embodiment of the present invention;

[0038] Figure 6 This is a schematic structural diagram of a control torque measurement device for a foldable coaxial bi-wing UAV system according to an embodiment of the present invention;

[0039] Figure 7 The horizontal coordinate of the embodiment of the present invention is 90- , the vertical axis is the rolling control torque Curve fitting diagram of .

[0040] Reference numerals:

[0041] 100-fuselage; 200-rotor motor; 300-rotor main shaft;

[0042] 400-upper rotor; 410-upper rotor hub; 420-upper rotor pitch hinge assembly; 421-upper rotor pitch rod; 422-upper rotor pitch hinge; 423-upper rotor pitch connecting rod; 424-upper rotor pitch rocker arm; 425-upper rotor swash plate support arm; 430-upper flap hinge; 440-upper swing hinge; 450-upper blade;

[0043] 500-lower rotor; 510-lower flap hinge; 520-lower swing hinge; 530-lower blade;

[0044] Phase Angle . DETAILED DESCRIPTION

[0045] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0046] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0047] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0048] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0049] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0050] Reference Figure 1 , according to the rotor pitch rocker arm size optimization method of the first aspect of the present invention, for a helicopter with a foldable rotor, comprising:

[0051] Step 1, overhang based on flap hinge , get the flapping frequency of the rotor , Locke number , time constant ;

[0052] Among them, Locke number Characterizes the ratio of the aerodynamic force to the inertial force of the blade.

[0053] Step 2, based on the swing frequency , Locke number , time constant , lateral control input pitch angle and longitudinal control input pitch angle , get the taper angle of the rotor , Back chamfer and side chamfer ;

[0054] Among them, the lateral control input pitch angle and longitudinal control input pitch angle It refers to the angle value input when the drone moves horizontally or vertically under the control of the operator.

[0055] Rotor taper angle It refers to the angle formed by the rotor and the horizontal plane during vertical flight. At this time, the rotor forms a rotor cone with the tip facing downward.

[0056] Rotor rear chamfer It means that during the forward flight, the rotor cone tilts backward, and the angle of the rotor cone tilting is the back chamfer. .

[0057] Rotor side chamfer It refers to the angle at which the rotor cone tilts to 90° during sideways flight, which is called the side chamfer. .

[0058] Step 3, based on the taper angle , Back chamfer and side chamfer , get the pitch control torque of the rotor and roll control torque ;

[0059] Step 4, based on pitch control torque or roll control torque , obtain the longitudinal periodic pitch value and the lateral periodic pitch value of the rotor;

[0060] Step 5: Obtain the phase angle of the pitch rocker arm in reverse order through the longitudinal periodic pitch value and the lateral periodic pitch value. , to obtain different phase angles of the variable pitch rocker arm Corresponding pitch control torque or roll control torque .

[0061] Specifically, the different phase angles of the variable pitch rocker arm are calculated Corresponding pitch control torque or roll control torque , with pitch control moment For example, when different phase angles are obtained Corresponding pitch control torque Then, the pitch control moment can be selected The UAV is designed with the phase angle corresponding to the maximum torque, so that the pitch control torque of the UAV at this time It will be larger than conventional designs and can be increased to 1.5 to 2 times of conventional designs, making the drone control response faster, more resistant to wind disturbances, and safer to fly.

[0062] Reference Figure 2 , Figure 3 and Figure 4 For ease of understanding, the following takes a foldable coaxial biplane drone as an example for exemplary explanation.

[0063] A foldable coaxial biplane drone comprises a cylindrical fuselage 100, a rotor motor 200, a rotor main shaft 300, an upper rotor 400 and a lower rotor 500.

[0064] The rotor main shaft 300 is fixedly mounted on the fuselage 100 , the stator of the rotor motor 200 is fixedly mounted on the rotor main shaft 300 , the rotor of the rotor motor 200 is coaxially arranged with the rotor main shaft 300 , and the upper rotor 400 and the lower rotor 500 are both fixedly connected to the rotor of the rotor motor 200 .

[0065] Reference Figure 4 and Figure 5 , wherein the upper rotor 400 includes an upper rotor hub 410, an upper rotor pitch hinge assembly 420, an upper flap hinge 430, an upper swing hinge 440 and an upper blade 450. The upper rotor hub 410 is fixedly connected to the rotor of the rotor motor 200, the upper rotor 400 pitch hinge assembly is mounted on the upper rotor hub 410 to drive the upper rotor 400 pitch hinge 422 to deflect within a certain range around the axis of the rotor main shaft 300 to achieve the steering of the UAV, the upper flap hinge 430 is mounted on the upper rotor pitch hinge assembly 420, the upper swing hinge 440 is mounted on the upper flap hinge 430, and the upper blade 450 is mounted on the upper swing hinge 440.

[0066] Reference Figure 4 and Figure 5 , wherein the upper rotor pitch change hinge assembly 420 includes an upper rotor pitch change rod 421, an upper rotor pitch change hinge 422, an upper rotor pitch change connecting rod 423, an upper rotor pitch change rocker arm 424, and an upper rotor swash plate support arm 425. The upper rotor pitch change rod 421 is fixedly connected to the upper rotor hub 410, and the axis of the upper rotor pitch change rod 421 is perpendicular to the axis of the rotor main shaft 300. The upper rotor pitch change hinge 422 is arranged on the side of the upper rotor pitch change rod 421, and the upper rotor pitch change rocker arm 424 is fixedly installed on the upper rotor 400 pitch change hinge 422. One end of the upper rotor pitch change connecting rod 423 is connected to the end of the upper rotor pitch change rocker arm 424 through the upper rotor pitch change rocker arm 424 bearing, and the other end is connected to the end of the upper rotor swash plate support arm 425 through a ball joint.

[0067] Reference Figure 6 In addition, the phase angle of the rotor pitch rocker arm It refers to the angle between the line connecting the center of the end bearing of the variable pitch rocker arm to the center of the rotor hub and the axis of the rotor variable pitch hinge. The phase angle can be changed by changing the size of the rotor variable pitch rocker arm. .

[0068] Among them, the flapping hinge, also called the horizontal hinge, is conventionally designed to set a horizontal axial hole at the root of the blade, which is connected to the rotor pitch hinge assembly through a pin. This connection method allows the blade to swing within a certain range. In this way, when the blade moves forward, due to the increase in lift, it naturally swings upward, and its actual direction of movement is no longer horizontal, but diagonally upward. The actual angle of attack of the blade is also reduced due to this movement, and the lift is reduced. When the blade moves backward, the lift is insufficient and it naturally falls. This movement of rotating and falling increases the actual angle of attack of the blade and increases the lift. At the same time, due to the existence of centrifugal force, the blade will have a tendency to straighten naturally, so it will not rise or fall infinitely under the action of lift, that is to say, the flapping amplitude of the blade is not infinite.

[0069] In addition, the folding function of the rotor can be realized by the flapping hinge, but when the folding function is realized, the flapping hinge extension It is inevitable that the size of the rotor blades will exceed or be equal to the size of the fuselage 100, so that when the rotor blades are folded, they can be folded to fit the fuselage 100, and the flapping hinge extension When the rotor is smaller than the size of the fuselage 100, the rotor will interfere with the fuselage 100 and cannot be completely folded to the side of the fuselage 100. For example, the rotor diameter is about 600 mm after unfolding, and the radius of the fuselage 100 is 140 mm. After folding, the rotor will fit the fuselage 100, so that the overall radius of the fuselage 100 after folding is only slightly larger than 140 mm.

[0070] Among them, the swing hinge, also called the "vertical hinge", is conventionally designed to set a vertical shaft hole at the root of the blade, which is connected to the rotor pitch hinge assembly through a pin. This connection method allows the blade to swing back and forth slightly, thereby avoiding bending or fatigue fracture at the root of the blade. In addition, the swing hinge can also be replaced by a flexible material.

[0071] In some specific embodiments of the present invention, in step 1, the waving frequency The calculation formula is as follows:

[0072]

[0073] Where P is the flapping frequency ratio, is the elastic coefficient of the flapping hinge, is the swing hinge extension, is the swing hinge mass moment, is the swing hinge moment of inertia, is the rotation speed of the rotor;

[0074] Locke number The calculation formula is as follows:

[0075]

[0076] in, is the air density, is the lift line slope coefficient of the blade airfoil, is the average aerodynamic chord length of the blade.

[0077] Time constant The calculation formula is as follows:

[0078]

[0079] in, is the rotor speed, is the Locke number.

[0080] In some specific embodiments of the present invention, in step 2, the taper angle of the rotor is obtained by using the first-order flapping dynamics equations. , Back chamfer and side chamfer , the specific equation is as follows:

[0081]

[0082] in, is the total moment angle, g is the gravity acceleration value, Δ is the correction coefficient of the rotor rotation direction, right rotation is 1, left rotation is -1, is the dynamic coupling ratio, To manipulate the coupling ratio, is the pitch angular velocity, is the rolling angular velocity.

[0083] It can be seen from the first-order dynamic flapping equations that the flapping hinge extension It will affect the flapping frequency ratio P, and then affect the flapping motion characteristics, that is, affect the taper angle of the rotor. , Back chamfer and side chamfer size.

[0084] In some specific embodiments of the present invention, in step 2, the dynamic coupling rate and manipulate the coupling ratio Calculated by the following formula:

[0085]

[0086] In some specific embodiments of the present invention, in step 3, the pitch control torque of the rotor is obtained by the aerodynamic torque calculation equation. and roll control torque , the specific equation is as follows:

[0087]

[0088] in, is the number of blades, is the dimensionless quantity of flapping hinge extension, and R is the rotor radius.

[0089] Specifically, in this embodiment, =2. From the above formula, we can know that the pitch control torque and roll control torque The calculation formula is relatively complicated. It is not a single variable lateral control input pitch angle. and longitudinal control input pitch angle is a function of the flapping hinge extension For example, when pitch control is required, input , When the pitch control moment The value is not the maximum, and the rolling control torque , that is, pitch and roll are coupled together, wasting part of the torque.

[0090] In some specific embodiments of the present invention, in step 5, the phase angle Pitch angle with lateral control input , Longitudinal control input pitch angle Through the following relationship:

[0091]

[0092] Specifically, by inputting the lateral control into the pitch angle and longitudinal control input pitch angle By associating the above formula, the coupling between pitch and roll can be eliminated, thereby improving the control torque of the corresponding channel.

[0093] Reference Figure 7 For ease of understanding, a specific embodiment is used as an example for exemplary description.

[0094] set up , , and then by modifying the phase angle of the pitch rocker arm , substituting into the above equation, the corresponding pitch control moment is calculated or roll control torque , with rolling control moment Take 2 as an example, the specific curve diagram is as follows: Figure 7 Shown

[0095] exist Figure 7 In the figure, the horizontal axis is 90- , the ordinate is the rolling control torque As can be seen from the figure, when the phase angle is 90° (corresponding to the horizontal axis of the figure above is 0°), the rolling control torque for ; When the phase angle When it is about 34° (corresponding to 56° on the horizontal axis in the figure above), the rolling control torque reaches its peak value, which is , the control torque is 161% of the original. It can be seen that by modifying the phase angle Size can significantly improve the control torque of the drone.

[0096] The unmanned helicopter according to the second embodiment of the present invention comprises: a phase angle of the variable pitch rocker arm The rotor pitch rocker arm size optimization method is determined according to the first aspect of the embodiment of the present invention.

[0097] The unmanned helicopter adopts the optimization method of the rotor pitch rocker arm size of the first aspect to produce a phase angle The corresponding variable pitch rocker arm is installed on the unmanned helicopter to further improve the control torque of the drone, which can generally be 1.5 to 2 times that of the conventional design, making the drone's control response faster, the ability to resist wind disturbance is stronger, and the flight is safer.

[0098] Reference Figure 2 , Figure 3 and Figure 4 In some specific embodiments of the present invention, the invention comprises a fuselage 100; an upper rotor 400 and a lower rotor 500 which are coaxially arranged, wherein the upper rotor 400 and the lower rotor 500 are arranged on the top of the fuselage 100, the upper rotor 400 comprises at least two upper rotor rotating units, and the lower rotor 500 comprises at least two lower rotor rotating units;

[0099] The upper rotor rotation unit includes an upper blade 450; an upper swing hinge 440, on which the upper blade 450 is mounted; an upper flap hinge 430, on which the upper flap hinge 430 extends. The radius is not less than the UAV fuselage 100, the upper swing hinge 440 is installed on the upper swing hinge 430, and the upper blade 450 rotates downward around the upper swing hinge 430 through the upper swing hinge 440 to fit on the fuselage 100;

[0100] The lower rotor rotation unit includes a lower blade 530; a lower swing hinge 520, on which the lower blade 530 is mounted; a lower flap hinge 510, on which the lower flap hinge 510 extends. The radius of the UAV fuselage 100 is not less than that of the UAV fuselage. The lower swing hinge 520 is installed on the lower swing hinge 510. The lower blade 530 rotates downward around the lower swing hinge 510 through the lower swing hinge 520 and fits onto the fuselage 100.

[0101] Specifically, the folding function of the drone is achieved through the upper swing hinge 430 and the lower swing hinge 510 .

[0102] In some specific embodiments of the present invention, the invention comprises a fuselage 100; an upper rotor 400 and a lower rotor 500 which are coaxially arranged, wherein the upper rotor 400 and the lower rotor 500 are arranged on the top of the fuselage 100, the upper rotor 400 comprises at least two upper rotor rotating units, and the lower rotor 500 comprises at least two lower rotor rotating units;

[0103] The upper rotor rotation unit includes an upper blade 450 whose root is made of a flexible material; an upper flapping hinge 430, the extension of which is not less than the radius of the UAV fuselage 100, the root of the upper blade 450 is installed on the upper flapping hinge 430, and the upper blade 450 is rotated downward to fit on the fuselage 100 through the upper flapping hinge 430;

[0104] The lower rotor rotating unit includes a lower blade 530 whose root is made of flexible material; a lower flapping hinge 510, the outward extension of the lower flapping hinge 510 is not less than the radius of the UAV fuselage 100, the root of the lower blade 530 is installed on the lower flapping hinge 510, and the lower blade 530 is rotated downward to fit onto the fuselage 100 through the lower flapping hinge 510.

[0105] Specifically, the flexible material at the root of the upper blade 450 or the lower blade 530 can replace the upper swing hinge 440 or the lower swing hinge 520 to allow the blade to swing slightly back and forth, thereby preventing the blade root from bending or fatigue fracture. The foldable function of the drone is also achieved through the upper swing hinge 430 and the lower swing hinge 510.

[0106] Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for optimizing the size of a rotor pitch rocker arm, for a helicopter with a flapping hinge and a foldable rotor, characterized in that: include: Step 1, based on the helicopter's flapping hinge extension , get the flapping frequency of the rotor , Locke number , time constant ; Step 2, based on the swing frequency , the Locke number , the time constant , lateral control input pitch angle and longitudinal control input pitch angle , get the taper angle of the rotor , Back chamfer and side chamfer ; Step 3, based on the taper angle , the rear chamfer and the side chamfer , get the pitch control torque of the rotor and roll control torque ; Step 4: Based on the pitch control moment or the roll control moment , obtain the longitudinal periodic pitch value and the lateral periodic pitch value of the rotor; Step 5, reversely obtain the phase angle of the pitch rocker arm through the longitudinal periodic pitch value and the lateral periodic pitch value , to obtain different phase angles of the variable pitch rocker arm The corresponding pitch control moment or the roll control moment ; In step 1, the waving frequency The calculation formula is as follows: Where P is the flapping frequency ratio, is the elastic coefficient of the flapping hinge, is the swing hinge extension, is the swing hinge mass moment, is the swing hinge moment of inertia, is the rotation speed of the rotor; The Locke number The calculation formula is as follows: in, is the air density, is the lift line slope coefficient of the blade airfoil, is the average aerodynamic chord length of the blade; The time constant The calculation formula is as follows: in, is the rotor speed, is the Locke number; In step 2, the taper angle of the rotor is obtained by the first-order flapping dynamics equations: , Back chamfer and side chamfer , the specific equation is as follows: in, is the total moment angle, g is the gravity acceleration value, Δ is the correction coefficient of the rotor rotation direction, right rotation is 1, left rotation is -1, is the dynamic coupling ratio, To manipulate the coupling ratio, is the pitch angular velocity, is the rolling angular velocity; In step 2, the dynamic coupling rate and manipulate the coupling ratio Calculated by the following formula: Where P is the flapping frequency ratio, is the Locke number; In step 3, the pitch control torque of the rotor is obtained through the aerodynamic torque calculation equation and roll control torque , the specific equation is as follows: in, is the number of blades, is the dimensionless quantity of flapping hinge extension, R is the rotor radius; In step 5, the phase angle The lateral control input pitch angle , the longitudinal control input pitch angle Through the following relationship: 。 2. An unmanned helicopter, characterized in that: include: The phase angle of the variable pitch rocker arm The rotor pitch rocker arm size optimization method according to claim 1 is determined.

3. The unmanned helicopter according to claim 2, characterized in that: The invention comprises a fuselage; an upper rotor and a lower rotor arranged coaxially, wherein the upper rotor and the lower rotor are arranged on the top of the fuselage, the upper rotor comprises no less than two upper rotor rotating units, and the lower rotor comprises no less than two lower rotor rotating units; The upper rotor rotation unit includes an upper blade; an upper swing hinge, on which the upper blade is mounted; an upper flap hinge, on which the upper flap hinge extends The radius of the upper swing hinge is not less than that of the UAV fuselage, the upper swing hinge is installed on the upper flap hinge, and the upper blade is rotated downward around the upper flap hinge through the upper swing hinge to fit the fuselage; The lower rotor rotation unit includes a lower blade; a lower swing hinge, on which the lower blade is mounted; a lower flap hinge, on which the lower flap hinge extends The radius of the UAV fuselage is not less than that of the UAV fuselage. The lower swing hinge is installed on the lower flap hinge, and the lower blade is rotated downward around the lower flap hinge through the lower swing hinge to fit the fuselage.

4. The unmanned helicopter according to claim 2, characterized in that: The invention comprises a fuselage; an upper rotor and a lower rotor arranged coaxially, wherein the upper rotor and the lower rotor are arranged on the top of the fuselage, the upper rotor comprises no less than two upper rotor rotating units, and the lower rotor comprises no less than two lower rotor rotating units; The upper rotor rotation unit comprises an upper blade whose root is made of a flexible material; an upper flapping hinge, and the upper flapping hinge has an extension The radius of the upper blade is not less than that of the UAV fuselage, the root of the upper blade is installed on the upper flapping hinge, and the upper blade is rotated downward to fit the fuselage through the upper flapping hinge; The lower rotor rotation unit comprises a lower blade whose root is made of a flexible material; a lower flapping hinge, wherein the lower flapping hinge has an outward extension The radius of the lower propeller blade is not less than that of the UAV fuselage, and the root of the lower propeller blade is installed on the lower flapping hinge, and the lower propeller blade is rotated downward to fit onto the fuselage through the lower flapping hinge.

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