A tail stand type unmanned aerial vehicle fixed-point hovering control method based on rudder surface vector distribution

Abstract

The application belongs to the field of flight control law design, in particular to a tail stand type unmanned aerial vehicle fixed point hovering control method based on rudder surface vector distribution, and the technical scheme is: the total position control amount of the rudder surface is determined by the distance between the current position of the unmanned aerial vehicle and the target position of the fixed point hovering, and the speed of the unmanned aerial vehicle approaching the target position of the fixed point hovering; the position control amount of each rudder surface is determined by the azimuth relationship between the line connecting the current position and the target position of the fixed point hovering and the body coordinate axis of the unmanned aerial vehicle; the engine throttle control instruction is determined by the height difference between the current height of the unmanned aerial vehicle and the target height of the fixed point hovering, and the upward speed of the unmanned aerial vehicle; the direction control amount of each rudder surface of the unmanned aerial vehicle is determined according to the target direction of the body coordinate axis of the unmanned aerial vehicle; and the control amount of each rudder surface is calculated according to the position control amount and the direction control amount of each rudder surface. The application utilizes vector distribution, so that the unmanned aerial vehicle can obtain the maximum rudder surface control efficiency in the forward direction, and avoids the control internal consumption among multiple rudder surfaces.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of flight control law design, and particularly relates to a tail seat type unmanned aerial vehicle fixed-point hovering control method based on rudder surface vector distribution. BACKGROUND

[0002] A vertical take-off and landing aircraft utilizes vertical upward thrust provided by an engine to overcome gravity, thereby realizing vertical take-off and landing. Such an aircraft can break away from dependence on an airport runway, has advantages such as flexible departure, high attendance rate and low support cost; in addition, the aircraft can take off and land on a ship, and has incomparable advantages over a ski-jump carrier-based aircraft in improving amphibious combat capability. The main types of vertical take-off and landing aircrafts developed so far include tail seat type, tilt-rotor type, rotor type, jet engine thrust turning type, ducted fan type, and hybrid type.

[0003] Among them, the tail seat type vertical take-off and landing unmanned aerial vehicle is a kind of aircraft whose whole body tilts during take-off and landing, which can adopt propellers, ducted propellers, turbojet engines and the like as power, and has characteristics such as light weight, small size and simple power system, and can take off and land in narrow spaces such as ship decks, mountains, gorges and alleys, and can be used to perform tasks such as reconnaissance, relay communication and attack after carrying a payload, and has a wide application prospect.

[0004] When the tail seat type vertical take-off and landing unmanned aerial vehicle hovers at a fixed point, the unmanned aerial vehicle needs to be moved from the current position to the target position, and the tail seat type vertical take-off and landing unmanned aerial vehicle is generally provided with multiple rudder surfaces, such as 4, 6, 8 or the like. If the roles of each rudder surface are specified, for example, some rudder surfaces are responsible for position control in the front-back direction, and other rudder surfaces are responsible for position control in the left-right direction, this will reduce the rudder surface control efficiency and fail to exert the capacity of all rudder surfaces at each moment. Therefore, how to reasonably distribute multiple rudder surfaces to achieve high rudder surface control efficiency and avoid control internal consumption among multiple rudder surfaces has become a difficult problem of fixed-point hovering.

[0005] Through retrieval of existing technologies, the method of the patent with the publication number CN116610134A is the closest to the present application, but it has some deficiencies: (1) the controller of the method described in the comparison file is a nonlinear adaptive controller, the control law structure is complex, and the calculation amount is large; (2) the method described in the comparison file does not embody the control of the position and direction of the aircraft during hovering, and only describes the control of three-channel moments, and the disclosed content cannot realize fixed-point hovering control. SUMMARY

[0006] In order to solve the problems and deficiencies in the prior art, the present application proposes a tail seat type unmanned aerial vehicle fixed-point hovering control method based on rudder surface vector distribution.

[0007] In order to achieve the above-mentioned purposes, the technical scheme provided by the present application is as follows:

[0008] A tail stand type unmanned aerial vehicle fixed point hovering control method based on rudder surface vector distribution, comprising the following steps:

[0009] Step one, using the distance between the current position of the unmanned aerial vehicle and the fixed point hovering target position, and the speed of the unmanned aerial vehicle approaching the fixed point hovering target position to determine the total position control amount of the rudder surface;

[0010] Step two, using the azimuth relationship between the line connecting the current position of the unmanned aerial vehicle and the fixed point hovering target position and the coordinate axis of the unmanned aerial vehicle body to determine the position control amount of each rudder surface of the unmanned aerial vehicle;

[0011] Step three, using the height difference between the current height of the unmanned aerial vehicle and the fixed point hovering target height, and the upward speed of the unmanned aerial vehicle to determine the engine throttle control instruction;

[0012] Step four, determining the direction control amount of each rudder surface of the unmanned aerial vehicle according to the target direction of the coordinate axis of the unmanned aerial vehicle body;

[0013] Step five, calculating the control amount of each rudder surface according to the position control amount and the direction control amount of each rudder surface.

[0014] Further, the specific steps of step one are as follows:

[0015] Step S11. Establish a ground reference coordinate system;

[0016] Step S12. Calculate the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system;

[0017] Step S13. Calculate the distance between the current position of the unmanned aerial vehicle and the fixed point hovering target position;

[0018] Step S14. Calculate the speed of the unmanned aerial vehicle approaching the fixed point hovering target position;

[0019] Step S15. Calculate the total position control amount of the rudder surface.

[0020] Still further, in the step S11, the ground reference coordinate system is established, comprising:

[0021] Taking the fixed point hovering target position as the coordinate origin O, the geographic north direction as the positive direction of the coordinate axis OX, the geographic east direction as the positive direction of the coordinate axis OY, and OZ axis perpendicular to the OXY plane and pointing to the center of the earth as the positive direction.

[0022] Still further, in the step S12, the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system is as follows:

[0023] Still further, in the step S12, the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system is as follows:

[0024] wherein (X, Y, Z) is the coordinate value of the current position of the UAV in the ground reference coordinate system, R is the average radius of the Earth's equator, e is the Earth's flattening, H p is the current height of the UAV, H o is the target height of the fixed-point hovering, LON p is the longitude of the current position of the UAV, LAT p is the latitude of the current position of the UAV, LON o is the longitude of the target position of the fixed-point hovering, LAT o is the latitude of the target position of the fixed-point hovering.

[0025] Further, in the step S13, the method for calculating the distance between the current position of the UAV and the target position of the fixed-point hovering is:

[0026]

[0027] wherein ΔL is the distance between the current position of the UAV and the target position of the fixed-point hovering.

[0028] Further, in the step S14, the speed of the UAV approaching the target position of the fixed-point hovering is the projection of the current eastward speed and northward speed of the UAV on the line connecting the current position of the UAV and the target position of the fixed-point hovering, and the specific calculation method is:

[0029]

[0030] wherein V N is the current northward speed of the UAV, V E is the current eastward speed of the UAV, V L is the speed of the UAV approaching the target position of the fixed-point hovering. V N and V E can be measured by the on-board navigation equipment.

[0031] Further, in the step S15, the total position control amount of the control surface is obtained by the position controller, and the position controller is composed of a position control loop and a speed control loop of the UAV approaching the target position of the fixed-point hovering.

[0032] Further, the position control loop adopts a proportional control plus integral control structure of the distance ΔL between the current position of the UAV and the target position of the fixed-point hovering, and the specific structure is:

[0033]

[0034] wherein K L is the control parameter of the proportional control item of the position control, K IL is the control parameter of the integral control item of the position control, It is the speed control target for the UAV to approach the fixed hovering target position.

[0035] Furthermore, the speed control loop of the UAV approaching the fixed-point hovering target position adopts an integral control structure of the error between the speed of the UAV approaching the fixed-point hovering target position and the speed control target of the UAV approaching the fixed-point hovering target position, and uses the speed of the UAV approaching the fixed-point hovering target position as the damping term, specifically:

[0036]

[0037] Among them, K V K is the speed control damping parameter of the UAV approaching the fixed hovering target position, IV is the integral control parameter of the speed control of the UAV approaching the fixed hovering target position, δ L is the total position control quantity of the rudder surface.

[0038] Furthermore, the specific steps of step 2 are:

[0039] Step S21: Calculate the azimuth of the line connecting the current position of the UAV and the fixed hovering target position;

[0040] Step S22: Establishing a body coordinate system;

[0041] Step S23: Calculate the azimuth difference between the line connecting the current position of the UAV and the fixed hovering target position and the coordinate axis of the UAV body;

[0042] Step S24: Allocate the total control amount of the control surface position to each control surface of the UAV through vector allocation.

[0043] Furthermore, in step S21, the azimuth angle of the line connecting the current position of the drone to the fixed hovering target position is defined as: the angle between the vector from the current position of the drone to the fixed hovering target position and the geographic north, and starting from the geographic north, the azimuth angle is positive when the vector rotates eastward, otherwise it is negative. The numerical range of the azimuth angle is [-180°, 180°]. The specific calculation method of the azimuth angle is:

[0044]

[0045] in, It is the azimuth of the line connecting the current position of the UAV to the fixed hovering target position.

[0046] Furthermore, in step S22, establishing the body coordinate system includes:

[0047] The center of gravity of the aircraft is O p The center of the propeller or the center of the engine tail nozzle is the coordinate origin O pThe line connecting the current position of the UAV and the target position of the hovering is O p X p The axis is perpendicular to the longitudinal symmetry plane of the fuselage, and positive when pointing to the right wing; O p Y p The axis is perpendicular to the longitudinal symmetry plane of the fuselage, and positive when pointing to the right wing; O p Z p The axis is determined according to the right-hand rule.

[0048] Further, the method for calculating the azimuth angle difference between the line connecting the current position of the UAV and the target position of the hovering and the UAV body coordinate axis in step S23 is:

[0049]

[0050] wherein, The azimuth angle difference between the line connecting the current position of the UAV and the target position of the hovering and the UAV body coordinate axis is in the range of [-180°, 180°], The azimuth angle of the UAV body coordinate axis is defined as: the azimuth angle of the line connecting the current position of the UAV and the target position of the hovering in the UAV body coordinate system O p Z p The angle between the axis and the geographic north, that is, the yaw angle, is measured by the on-board attitude sensor, The value of the azimuth angle of the UAV body coordinate axis is in the range of [-180°, 180°].

[0051] Further, the total position control amount of the rudder surface in step S24 is distributed according to the corresponding distribution method of the UAV rudder surface layout form, and the specific features of the rudder surface layout form include: the number of UAV rudder surfaces and the distribution position of the rudder surfaces in the duct.

[0052] Preferably, the present application proposes three tail seat type UAV rudder surface layout forms:

[0053] The tail seat type UAV rudder surface layout form A: the number of UAV rudder surfaces is 4, and they are evenly distributed in a radial manner around the center of the duct, that is, the included angle of the rotation shafts of any two adjacent rudder surfaces is 90°, wherein the rotation shafts of two rudder surfaces are in the O p X p Z p plane, and in the O p Z p The rudder surface on the negative side of the O

[0054] The symbol definition of each rudder surface in the layout form A: when viewed from the tail to the head, the A1 rudder surface is towards the O p Y p The symbol of the rudder surface is positive when it deflects to the negative direction of the O p Yp The sign of the control surface is positive when it deflects in the positive direction of the axis, otherwise it is negative; the A2 control surface is toward O p Z p The sign of the control surface is positive when it deflects in the positive direction of the axis, otherwise it is negative; the A4 control surface is toward O p Z p The sign of the control surface is positive when it deflects in the positive direction of the axis, otherwise it is negative;

[0055] For layout form A, the method of distributing the total position control quantity of the control surface to each control surface of the unmanned aerial vehicle is:

[0056]

[0057]

[0058] wherein, is the position control quantity of the No. 1 control surface, is the position control quantity of the No. 2 control surface, is the position control quantity of the No. 3 control surface, is the position control quantity of the No. 4 control surface.

[0059] Preferably, the tail seat type unmanned aerial vehicle control surface layout form B is: the number of unmanned aerial vehicle control surfaces is 6, and is uniformly distributed in a radial manner around the center of the duct, that is, the included angle of the rotation shafts of any two adjacent control surfaces is 60°, wherein the rotation shafts of two control surfaces are in the positive direction of the X axis of the body coordinate system O p X p Z p in the plane, and on the positive side of the X axis of the body coordinate system O p Z p The control surface on the negative side of the axis is marked as the B1 control surface, and the remaining control surfaces are sequentially marked as the B2 control surface, the B3 control surface, the B4 control surface, the B5 control surface, and the B6 control surface in the counterclockwise direction as viewed from the tail to the head direction of the unmanned aerial vehicle;

[0060] The sign definition of each control surface of the layout form B is: as viewed from the tail to the head direction of the unmanned aerial vehicle, the B1 control surface is toward O p Y p The sign of the control surface is positive when it deflects in the positive direction of the axis, otherwise it is negative; the B4 control surface is toward O p Y p The sign of the control surface is positive when it deflects in the positive direction of the axis, otherwise it is negative; the B2 control surface is toward the B1 control surface when it deflects in the positive direction of the axis, otherwise it is negative; the B3 control surface is toward the B2 control surface when it deflects in the positive direction of the axis, otherwise it is negative; the B5 control surface is toward the B6 control surface when it deflects in the positive direction of the axis, otherwise it is negative; the B6 control surface is toward the B1 control surface when it deflects in the positive direction of the axis, otherwise it is negative;

[0061] For the unmanned aerial vehicle control surface layout form B, the method of distributing the total position control quantity of the control surface to each control surface of the unmanned aerial vehicle is:

[0062]

[0063]

[0064] in, is the position control value of the No. 1 rudder surface, is the position control value of the No. 2 rudder surface, is the position control value of the No. 3 rudder surface, is the position control value of the No. 4 rudder surface, is the position control value of the No. 5 rudder surface, It is the position control value of the No. 6 control surface.

[0065] Preferably, the tail-seat UAV rudder layout form C: the number of the UAV rudders is 8, and they are evenly distributed radially around the center of the duct, that is, the angle between the rotation axes of any two adjacent rudders is 45°, and the rotation axes of two of the rudders are in the body coordinate system O p X p Z p In the plane, and at O p Z p The rudder surface on the negative axis is marked as C1. Looking from the tail to the nose, the remaining rudder surfaces are marked in counterclockwise order as C2, C3, C4, C5, C6, C7, and C8.

[0066] Symbols of the control surfaces in layout C: When looking from the tail to the nose, the control surface C1 is facing O. p Y p When the axis deflects in the negative direction, the sign of the rudder surface is positive, otherwise it is negative; the C5 rudder surface is O p Y p When the axis deflects in the negative direction, the sign of the rudder surface is positive, otherwise it is negative; the sign of the C3 rudder surface is O p Z p When the axis deflects in the positive direction, the sign of the rudder is positive, otherwise it is negative; the C7 rudder is O p Z p When the axis deflects in the positive direction, the sign of the rudder surface is positive, otherwise it is negative; when the C2 rudder surface deflects towards the C1 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the C4 rudder surface deflects towards the C3 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the C8 rudder surface deflects towards the C1 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the C6 rudder surface deflects towards the C7 rudder surface, the sign of the rudder surface is positive, otherwise it is negative;

[0067] For the UAV control surface layout C, the method of allocating the total control amount of the control surface to each control surface of the UAV is:

[0068]

[0069]

[0070]

[0071]

[0072] wherein, is a position control quantity of the first rudder surface, is a position control quantity of the second rudder surface, is a position control quantity of the third rudder surface, is a position control quantity of the fourth rudder surface, is a position control quantity of the fifth rudder surface, is a position control quantity of the sixth rudder surface, is a position control quantity of the seventh rudder surface, is a position control quantity of the eighth rudder surface.

[0073] As can be seen from the position control quantity determination methods of the three rudder surface layout forms, the meaning of vector distribution is to distribute the total position control quantity of the rudder surfaces to each rudder surface of the UAV, and the total control effect of all the rudder surfaces is equivalent to the total position control quantity of the rudder surfaces. Obviously, the position control quantity of each rudder surface is the actual rudder surface control quantity, and the total position control quantity of the rudder surfaces is a virtual quantity.

[0074] Further, the specific steps of step three are:

[0075] Step S31. Designing a UAV height control loop, the output quantity of which is a skyward speed control target;

[0076] Step S32. Based on the skyward speed control target obtained in step S31, designing a UAV skyward speed control loop, the output quantity of which is an engine throttle control instruction.

[0077] Further, in step S31, the UAV height control loop adopts a proportional control structure of height difference, specifically:

[0078]

[0079] wherein, K H is a height control proportional term control parameter, H is the current height of the UAV, H g is a fixed-point hovering target height, is a skyward speed control target.

[0080] Further, in step S32, the UAV skyward speed control loop adopts a proportional control plus integral control structure of the error between the skyward speed and the skyward speed control target, specifically:

[0081]

[0082] wherein, is the proportional control parameter of the heading velocity control, is the integral control parameter of the heading velocity control, is the heading velocity of the UAV, T is the engine throttle control command.

[0083] Further, the step four is specifically as follows:

[0084] Step S41. Designing a UAV direction controller, and the output of the loop is the total direction control amount of the rudder surface;

[0085] Step S42. According to the rudder surface distribution strategy, the total direction control amount of the rudder surface is distributed to each rudder surface of the UAV.

[0086] Further, in the step S41, the UAV direction controller adopts a proportional control plus integral control structure of the difference between the yaw angle and the yaw angle target, which is specifically as follows:

[0087]

[0088] wherein, is the proportional control parameter of the yaw angle target control, is the integral control parameter of the yaw angle target control, is the yaw angle, is the yaw angle target, is the total direction control amount of the rudder surface.

[0089] Further, the yaw angle target is determined by the flight task, for example, the airborne photoelectric ball head needs to be aligned with a certain direction for continuous tracking shooting, or the airborne weapon needs to be aimed at a certain direction. The method proposed in the present application can control the yaw angle target while controlling the position of the UAV, that is, the UAV can always align the body with a certain direction during movement.

[0090] Further, in the step S42, the total direction control amount of the rudder surface adopts different distribution methods according to different UAV rudder surface layout forms.

[0091] If the UAV rudder surface is in the layout form A, the method for distributing the total direction control amount of the rudder surface to each rudder surface of the UAV is as follows:

[0092]

[0093]

[0094] wherein, is the direction control amount of the No. 1 rudder surface, is the direction control amount of the No. 2 rudder surface, is the direction control amount of the 3rd rudder surface, is the direction control amount of the 4th rudder surface.

[0095] Further, if the rudder surface of the UAV is in the layout form B in the step S42, the method of distributing the total direction control amount of the rudder surface to each rudder surface of the UAV is:

[0096]

[0097]

[0098] wherein, is the direction control amount of the 1st rudder surface, is the direction control amount of the 2nd rudder surface, is the direction control amount of the 3rd rudder surface, is the direction control amount of the 4th rudder surface, is the direction control amount of the 5th rudder surface, is the direction control amount of the 6th rudder surface.

[0099] Further, if the rudder surface of the UAV is in the layout form C in the step S42, the method of distributing the total direction control amount of the rudder surface to each rudder surface of the UAV is:

[0100]

[0101]

[0102] wherein, is the direction control amount of the 1st rudder surface, is the direction control amount of the 2nd rudder surface, is the direction control amount of the 3rd rudder surface, is the direction control amount of the 4th rudder surface, is the direction control amount of the 5th rudder surface, is the direction control amount of the 6th rudder surface, is the direction control amount of the 7th rudder surface, is the direction control amount of the 8th rudder surface.

[0103] As can be seen from the above-mentioned methods of determining the direction control amount of each rudder surface in the three layout forms of the rudder surface, the meaning of the vector distribution is to distribute the total direction control amount of the rudder surface to each rudder surface of the UAV, and the total control effect of all the rudder surfaces is equivalent to the total direction control amount of the rudder surface. Obviously, the direction control amount of each rudder surface is the actual rudder surface control amount, and the total direction control amount of the rudder surface is a virtual amount.

[0104] Further, the step five is specifically:

[0105] If the unmanned aerial vehicle control surface is in layout form A, the calculation method of the control amount of each control surface is as follows:

[0106]

[0107]

[0108]

[0109]

[0110] wherein, δ A1 is the control amount of the first control surface, δ A2 is the control amount of the second control surface, δ A3 is the control amount of the third control surface, and δ A4 is the control amount of the fourth control surface.

[0111] Further, the step five is specifically as follows:

[0112] If the unmanned aerial vehicle control surface is in layout form B, the calculation method of the control amount of each control surface is as follows:

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119] wherein, δ B1 is the control amount of the first control surface, δ B2 is the control amount of the second control surface, δ B3 is the control amount of the third control surface, δ B4 is the control amount of the fourth control surface, δ B5 is the control amount of the fifth control surface, and δ B6 is the control amount of the sixth control surface.

[0120] Further, the step five is specifically as follows:

[0121] If the unmanned aerial vehicle control surface is in layout form C, the calculation method of the control amount of each control surface is as follows:

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130] wherein, δ C1 is the control amount of the first rudder surface, δ C2 is the control amount of the second rudder surface, δ C3 is the control amount of the third rudder surface, δ C4 is the control amount of the fourth rudder surface, δ C5 is the control amount of the fifth rudder surface, δ C6 is the control amount of the sixth rudder surface, δ C7 is the control amount of the seventh rudder surface, and δ C8 is the control amount of the eighth rudder surface.

[0131] The present application has the advantages that:

[0132] 1. The tail seat type unmanned aerial vehicle fixed point hovering control method based on rudder surface vector distribution disclosed in the present application utilizes vector distribution, so that the unmanned aerial vehicle can always obtain the maximum rudder surface control efficiency in the forward direction, and the control internal consumption among multiple rudder surfaces is avoided.

[0133] 2. The fixed point hovering control method can control the yaw angle target at the same time when controlling the position of the unmanned aerial vehicle, that is, the unmanned aerial vehicle can always align the body to a certain direction during movement, which is very beneficial to the flight tasks such as continuous tracking and shooting of the airborne photoelectric ball head and weapon aiming.

[0134] 3. The position controller and the direction controller of the fixed point hovering control method adopt the PID control structure, the flight control law algorithm is simple, and the engineering implementation is convenient. BRIEF DESCRIPTION OF DRAWINGS

[0135] Figure 1 The figure is the flow chart of the method of the present application;

[0136] Figure 2 The figure is the schematic diagram of the body coordinate system;

[0137] Figure 3 The figure is the schematic diagram of the rudder surface layout form A;

[0138] Figure 4 The figure is the schematic diagram of the rudder surface layout form B;

[0139] Figure 5 Schematic diagram of rudder layout type C. DETAILED DESCRIPTION

[0140] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are intended to explain the present invention rather than to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0141] The specific implementation method of the present invention is described below with reference to the accompanying drawings and examples, but the present invention is not limited to this embodiment.

[0142] To facilitate understanding of the embodiments of the present invention, Figure 2 As shown, the body coordinate system of the tail-seat UAV is defined as follows: the center of gravity of the aircraft is O p The center of the propeller or the center of the engine tail nozzle is the coordinate origin O p The line connecting the p X p Axis, and pointing to the direction of the nose is positive; O p Y p The axis is perpendicular to the longitudinal symmetry plane of the fuselage and points to the right wing; p Z p The axes are determined according to the right-hand rule.

[0143] Example 1

[0144] As attached Figure 3 As shown in FIG. 1 , the layout of the rudder surfaces of the tail-seat UAV described in this embodiment is as follows: the UAV has four rudder surfaces, which are evenly distributed radially around the center of the duct, that is, the angle between the rotation axes of any two adjacent rudder surfaces is 90°, and the rotation axes of two of the rudder surfaces are in the body coordinate system O p X p Z p In the plane, and at O p Z p The rudder surface on the negative axis side is marked as rudder surface A1. Looking from the tail to the nose, the remaining rudder surfaces are marked as rudder surface A2, rudder surface A3, and rudder surface A4 in a counterclockwise direction.

[0145] The symbols of the rudder surfaces of the tail-seat UAV described in this embodiment are defined as follows: when looking from the tail to the nose, the rudder surface A1 is facing O p Y p When the axis deflects in the negative direction, the sign of the rudder surface is positive, otherwise it is negative; the sign of the rudder surface A3 is O p Yp The sign of the control surface is positive when the axis is deflected in the negative direction, otherwise it is negative; the A2 control surface is facing O p Z p The sign of the control surface is positive when the axis is deflected in the positive direction, otherwise it is negative; the A4 control surface is facing O p Z p The sign of the control surface is positive when the axis is deflected in the positive direction, otherwise it is negative.

[0146] As shown in the accompanying Figure 1 A tail stand unmanned aerial vehicle fixed point hovering control method based on control surface vector distribution, the specific steps are as follows:

[0147] Step 1: determine the total position control amount of the control surface by using the distance between the current position of the unmanned aerial vehicle and the fixed point hovering target position, and the speed of the unmanned aerial vehicle approaching the fixed point hovering target position, the specific steps are as follows:

[0148] Step S11. Establish a ground reference coordinate system;

[0149] Step S12. Calculate the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system;

[0150] Step S13. Calculate the distance between the current position of the unmanned aerial vehicle and the fixed point hovering target position;

[0151] Step S14. Calculate the speed of the unmanned aerial vehicle approaching the fixed point hovering target position;

[0152] Step S15. Calculate the total position control amount of the control surface.

[0153] Further, in the step S11, the ground reference coordinate system is established, including: taking the fixed point hovering target position as the coordinate origin O, the geographic north direction as the positive direction of the coordinate axis OX, the geographic east direction as the positive direction of the coordinate axis OY, and OZ axis perpendicular to OXY plane and pointing to the positive direction of the earth center.

[0154] Further, in the step S12, the calculation formula of the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system is:

[0155]

[0156] Where (X, Y, Z) is the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system, R is the average radius of the earth equator, e is the earth flattening, H p is the current height of the unmanned aerial vehicle, H o is the fixed point hovering target height, LON p is the longitude of the current position of the unmanned aerial vehicle, LAT p is the latitude of the current position of the unmanned aerial vehicle, LON o is the longitude of the fixed point hovering target position, LAT oLatitude of the hovering target position.

[0157] Further, in the step S13, the method for calculating the distance between the current position of the UAV and the hovering target position is:

[0158]

[0159] wherein, ΔL is the distance between the current position of the UAV and the hovering target position.

[0160] Further, in the step S14, the speed of the UAV approaching the hovering target position is the projection of the current eastward speed and northward speed of the UAV on the line connecting the current position of the UAV and the hovering target position, and the specific calculation method is:

[0161]

[0162] wherein, V N is the current northward speed of the UAV, V E is the current eastward speed of the UAV, V L is the speed of the UAV approaching the hovering target position. V N and V E can be measured by the on-board navigation equipment.

[0163] Further, in the step S15, the total position control amount of the control surface is obtained by the position controller, and the position controller is composed of a position control loop and a speed control loop.

[0164] Further, the position control loop adopts a proportional control plus integral control structure of the distance ΔL between the current position of the UAV and the hovering target position, and the specific structure is:

[0165]

[0166] wherein, K L is the control parameter of the proportional item of the position control, K IL is the control parameter of the integral item of the position control, is the speed control target of the UAV approaching the hovering target position.

[0167] Further, the speed control loop adopts an integral control structure of the speed error, and takes the speed as the damping item, and the specific structure is:

[0168]

[0169] wherein, K V is the control parameter of the damping item of the speed control, K IV is the control parameter of the integral item of the speed control, δ L is the total position control amount of the control surface.

[0170] Step two: determine the position control amount of each rudder of the UAV by the azimuth relationship between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the coordinate axis of the UAV body, the specific steps are as follows:

[0171] Step S21. Calculate the azimuth angle of the line connecting the current position of the UAV to the target position of the fixed-point hovering.

[0172] Step S22. Calculate the azimuth angle difference between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the coordinate axis of the UAV body.

[0173] Step S23. Distribute the total position control amount of the rudder to each rudder of the UAV by vector distribution.

[0174] Further, in the step S21, the azimuth angle of the line connecting the current position of the UAV to the target position of the fixed-point hovering is defined as the angle between the vector pointing from the current position of the UAV to the target position of the fixed-point hovering and the geographic north, and the vector is rotated eastward from the geographic north, and the sign of the azimuth angle is positive, otherwise it is negative, and the numerical range of the azimuth angle is [-180°, 180°]. The specific calculation method of the azimuth angle is as follows:

[0175]

[0176] Wherein, is the azimuth angle of the line connecting the current position of the UAV to the target position of the fixed-point hovering.

[0177] Further, in the step S22, the calculation method of the azimuth angle difference between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the coordinate axis of the UAV body is as follows:

[0178]

[0179] Wherein, is the azimuth angle difference between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the coordinate axis of the UAV body, and the numerical range is [-180°, 180°]. is the azimuth angle of the coordinate axis of the UAV body, which is defined as the angle between the O p Z p axis of the UAV body coordinate system and the geographic north, that is, the yaw angle, which is measured by the on-board attitude sensor, The numerical range of is [-180°, 180°].

[0180] Further, in the step S23, the distribution method of the total position control amount of the rudder is as follows:

[0181]

[0182]

[0183] wherein, is a position control quantity of the No. A1 rudder surface, is a position control quantity of the No. A2 rudder surface, is a position control quantity of the No. A3 rudder surface, is a position control quantity of the No. A4 rudder surface.

[0184] Step three: determine the engine throttle control instruction by using the height difference between the current height of the UAV and the target height of the point hovering, and the skyward speed of the UAV, and the specific steps are as follows:

[0185] Step S31. Design a UAV height control loop, and the output quantity of the loop is a skyward speed control target;

[0186] Step S32. Based on the skyward speed control target obtained in step S31, design a UAV skyward speed control loop, and the output quantity of the loop is an engine throttle control instruction.

[0187] Further, in step S31, the UAV height control loop adopts a proportional control structure of the height difference, and specifically:

[0188]

[0189] wherein, K H is a height control proportional term control parameter, H is the current height of the UAV, and H g is a target height of the point hovering, is a skyward speed control target.

[0190] Further, in step S32, the UAV skyward speed control loop adopts a proportional control plus integral control structure of the skyward speed and the error of the skyward speed control target, and specifically:

[0191]

[0192] wherein, is a skyward speed control proportional term control parameter, is a skyward speed control integral term control parameter, is the skyward speed of the UAV, and δ T is an engine throttle control instruction.

[0193] Step four: determine the direction control quantity of each rudder surface of the UAV according to the target direction of the body coordinate axis of the UAV, and the specific steps are as follows:

[0194] Step S41. Design a UAV direction controller, and the output quantity of the loop is a total direction control quantity of the rudder surface;

[0195] Step S42. According to the rudder distribution strategy, the total direction control amount of the rudder is distributed to each rudder of the UAV.

[0196] Further, in the step S41, the yaw angle and the yaw angle target difference proportional control plus integral control structure is adopted by the UAV direction controller, specifically:

[0197]

[0198] Wherein, is the yaw angle target control proportional control parameter, is the yaw angle target control integral control parameter, is the yaw angle, is the yaw angle target, is the total direction control amount of the rudder.

[0199] Further, in the step S42, the distribution method of the total direction control amount of the rudder is:

[0200]

[0201]

[0202] Wherein, is the direction control amount of the A1 rudder, is the direction control amount of the A2 rudder, is the direction control amount of the A3 rudder, is the direction control amount of the A4 rudder.

[0203] Step five: according to the position control amount and the direction control amount of each rudder, the control amount of each rudder is calculated, specifically:

[0204]

[0205]

[0206]

[0207]

[0208] Wherein, δ A1 is the control amount of the No.1 rudder, δ A2 is the control amount of the No.2 rudder, δ A3 is the control amount of the No.3 rudder, and δ A4 is the control amount of the No.4 rudder.

[0209] Embodiment 2

[0210] As shown in the accompanying Figure 4As shown in the figure, the layout of the rudder surfaces of the tail-seat UAV in this embodiment is as follows: the number of the UAV rudder surfaces is 6, and they are evenly distributed radially around the center of the duct, that is, the angle between the rotation axes of any two adjacent rudder surfaces is 60°, and the rotation axes of two of the rudder surfaces are in the body coordinate system O p X p Z p In the plane, and at O p Z p The rudder surface on the negative side of the axis is marked as rudder surface B1. Looking from the tail to the nose of the aircraft, the remaining rudder surfaces are marked in a counterclockwise direction as rudder surface B2, rudder surface B3, rudder surface B4, rudder surface B5, and rudder surface B6.

[0211] The symbols of the rudder surfaces of the tail-seat UAV described in this embodiment are defined as follows: when looking from the tail to the nose, the rudder surface B1 is facing O p Y p When the axis deflects in the negative direction, the sign of the rudder surface is positive, otherwise it is negative; the sign of the rudder surface B4 is O p Y p When the axis deflects in the negative direction, the rudder surface sign is positive, otherwise it is negative; when rudder surface B2 deflects toward rudder surface B1, the rudder surface sign is positive, otherwise it is negative; when rudder surface B3 deflects toward rudder surface B2, the rudder surface sign is positive, otherwise it is negative; when rudder surface B5 deflects toward rudder surface B6, the rudder surface sign is positive, otherwise it is negative; when rudder surface B6 deflects toward rudder surface B1, the rudder surface sign is positive, otherwise it is negative.

[0212] As attached Figure 1 As shown in FIG, a tail-seat UAV fixed-point hovering control method based on rudder vector allocation is described, and the specific steps are as follows:

[0213] Step 1: Use the distance between the current position of the UAV and the fixed hovering target position, and the speed at which the UAV approaches the fixed hovering target position to determine the total position control value of the rudder surface. The specific steps are as follows:

[0214] Step S11. Establishing a ground reference coordinate system;

[0215] Step S12: Calculate the coordinate value of the current position of the UAV in the ground reference coordinate system;

[0216] Step S13: Calculate the distance between the current position of the drone and the fixed hovering target position;

[0217] Step S14: Calculate the speed of the UAV approaching the fixed hovering target position;

[0218] Step S15: Calculate the total control amount of the control surface position.

[0219] Further, the step S11, the ground reference coordinate system is established, comprising: taking the fixed-point hovering target position as the coordinate origin O, the geographical north as the positive direction of the coordinate axis OX, the geographical east as the positive direction of the coordinate axis OY, and the OZ axis being perpendicular to the OXY plane and pointing to the center of the earth as the positive direction.

[0220] Further, the step S12, the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system is calculated by the following formula:

[0221]

[0222] Wherein, (X, Y, Z) is the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system, R is the average radius of the earth equator, e is the earth flattening, H p is the current height of the unmanned aerial vehicle, H o is the fixed-point hovering target height, LON p is the longitude of the current position of the unmanned aerial vehicle, LAT p is the latitude of the current position of the unmanned aerial vehicle, LON o is the longitude of the fixed-point hovering target position, LAT o is the latitude of the fixed-point hovering target position.

[0223] Further, the step S13, the distance between the current position of the unmanned aerial vehicle and the fixed-point hovering target position is calculated by the following method:

[0224]

[0225] Wherein, ΔL is the distance between the current position of the unmanned aerial vehicle and the fixed-point hovering target position.

[0226] Further, the step S14, the speed of the unmanned aerial vehicle approaching the fixed-point hovering target position is the projection of the current eastward speed and northward speed of the unmanned aerial vehicle on the line connecting the current position of the unmanned aerial vehicle and the fixed-point hovering target position, and the specific calculation method is as follows:

[0227]

[0228] Wherein, V N is the current northward speed of the unmanned aerial vehicle, V E is the current eastward speed of the unmanned aerial vehicle, V L is the speed of the unmanned aerial vehicle approaching the fixed-point hovering target position. V N and V E can be measured by the airborne navigation equipment.

[0229] Further, the step S15, the total position control amount of the rudder surface is obtained by the position controller, and the position controller is composed of the position control loop and the speed control loop.

[0230] Further, the position control loop adopts a proportional control plus integral control structure of the distance AL between the current position of the UAV and the target position of the point hovering, specifically:

[0231]

[0232] wherein, K L is a position control proportional term control parameter, K IL is a position control integral term control parameter, is a speed control target of the UAV approaching the target position of the point hovering.

[0233] Further, the speed control loop adopts an integral control structure of the speed error, and takes the speed as a damping term, specifically:

[0234]

[0235] wherein, K V is a speed control damping term control parameter, K IV is a speed control integral term control parameter, and δ L is the total position control amount of the rudder.

[0236] Step two: determine the position control amount of each rudder of the UAV by using the azimuth relationship between the line connecting the current position of the UAV to the target position of the point hovering and the coordinate axes of the UAV body, specifically:

[0237] Step S21. Calculate the azimuth angle of the line connecting the current position of the UAV to the target position of the point hovering.

[0238] Step S22. Calculate the azimuth angle difference between the line connecting the current position of the UAV to the target position of the point hovering and the coordinate axes of the UAV body.

[0239] Step S23. Distribute the total position control amount of the rudder to each rudder of the UAV by vector distribution.

[0240] Further, in step S21, the azimuth angle of the line connecting the current position of the UAV to the target position of the point hovering is defined as the included angle between the vector pointing from the current position of the UAV to the target position of the point hovering and the geographic north, and the vector is rotated eastward from the geographic north, and the sign of the azimuth angle is positive, otherwise it is negative, and the numerical range of the azimuth angle is [-180°, 180°]. The specific calculation method of the azimuth angle is:

[0241]

[0242] wherein, is the azimuth angle of the line connecting the current position of the UAV to the target position of the point hovering.

[0243] Further, the azimuth angle difference between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the body coordinate axis of the UAV in step S22 is calculated as follows:

[0244]

[0245] wherein, is the azimuth angle difference between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the body coordinate axis of the UAV, and the value range thereof is [-180°, 180°]. is the azimuth angle of the body coordinate axis of the UAV, and is defined as: the azimuth angle of the body coordinate system O p Z p of the body coordinate axis of the UAV and the geographic north, i.e. the yaw angle, is measured by the on-board attitude sensor, the value range of is [-180°, 180°].

[0246] Further, the distribution method of the total position control amount of the rudder in step S23 is as follows:

[0247]

[0248]

[0249] wherein, is the position control amount of the No. 1 rudder, is the position control amount of the No. 2 rudder, is the position control amount of the No. 3 rudder, is the position control amount of the No. 4 rudder, is the position control amount of the No. 5 rudder, is the position control amount of the No. 6 rudder.

[0250] Step three: determining the engine throttle control command by using the height difference between the current height of the UAV and the target height of the fixed-point hovering and the skyward speed of the UAV, and the specific steps are as follows:

[0251] Step S31. Designing a UAV height control loop, and the output of the loop is the skyward speed control target;

[0252] Step S32. Based on the skyward speed control target obtained in step S31, designing a UAV skyward speed control loop, and the output of the loop is the engine throttle control command.

[0253] Further, in step S31, the UAV height control loop adopts a proportional control structure of the height difference, and the specific structure is as follows:

[0254]

[0255] wherein, K His the height control proportional term control parameter, H is the current height of the UAV, H g is the target height for fixed-point hovering, It is the target for celestial speed control.

[0256] Furthermore, in step S32, the UAV trolley speed control loop adopts a proportional control plus integral control structure of the trolley speed and the trolley speed control target error, specifically:

[0257]

[0258] in, is the control parameter of the celestial velocity proportional term, is the integral control parameter of the celestial velocity control, is the celestial speed of the UAV, δ T It is the engine throttle control command.

[0259] Step 4: Determine the directional control amount of each rudder surface of the drone based on the target direction of the drone's body coordinate axis. The specific steps are as follows:

[0260] Step S41. Design the UAV directional controller, the output of which is the total directional control value of the rudder;

[0261] Step S42: Allocate the total directional control amount of the rudder to each rudder of the UAV according to the rudder allocation strategy.

[0262] Furthermore, in step S41, the UAV direction controller adopts a proportional control plus integral control structure of the difference between the yaw angle and the yaw angle target, specifically:

[0263]

[0264] in, is the proportional control parameter for the yaw angle target control, is the integral control parameter for yaw angle target control, is the yaw angle, is the yaw angle target, is the total directional control quantity of the rudder surface.

[0265] Furthermore, the method for allocating the total directional control amount of the rudder surface in step S42 is:

[0266]

[0267]

[0268] in, is the directional control value of the No. 1 control surface, is the direction control value of the No. 2 rudder surface, Position control amount of the 3rd rudder surface, Position control amount of the 4th rudder surface, Position control amount of the 5th rudder surface, Position control amount of the 6th rudder surface.

[0269] Step five: according to the position control amount and the direction control amount of each rudder surface, the control amount of each rudder surface is calculated, specifically:

[0270]

[0271]

[0272]

[0273]

[0274]

[0275]

[0276] Wherein, δ B1 is the control amount of the 1st rudder surface, δ B2 is the control amount of the 2nd rudder surface, δ B3 is the control amount of the 3rd rudder surface, δ B4 is the control amount of the 4th rudder surface, δ B5 is the control amount of the 5th rudder surface, δ B6 is the control amount of the 6th rudder surface.

[0277] Embodiment 3

[0278] As shown in the accompanying Figure 5 , the rudder surface layout form of the tail seat type unmanned aerial vehicle described in this embodiment is: the number of unmanned aerial vehicle rudder surfaces is 8, and is uniformly distributed in a radial manner around the duct center, that is, the included angle of the rotation shafts of any two adjacent rudder surfaces is 45°, wherein the rotation shafts of two rudder surfaces are in the O p X p Z p plane, and the rudder surface on the negative side of the O p Z p axis is marked as the C1 rudder surface, and when viewed from the tail to the head direction, the remaining rudder surfaces are sequentially marked as the C2 rudder surface, the C3 rudder surface, the C4 rudder surface, the C5 rudder surface, the C6 rudder surface, the C7 rudder surface, and the C8 rudder surface in a counterclockwise direction.

[0279] The symbol definition of each rudder surface of the tail seat type unmanned aerial vehicle described in this embodiment is: when viewed from the tail to the head direction, the C1 rudder surface deflects towards the O p Y p axis negative direction, the symbol of the rudder surface is positive, otherwise it is negative; the C5 rudder surface deflects towards the Op Y p The sign of the control surface is positive when it deflects in the negative direction of the axis, otherwise it is negative; the C3 control surface deflects towards the C1 control surface p Z p The sign of the control surface is positive when it deflects in the positive direction of the axis, otherwise it is negative; the C7 control surface deflects towards the C1 control surface p Z p The sign of the control surface is positive when it deflects in the positive direction of the axis, otherwise it is negative; the C2 control surface deflects towards the C1 control surface, the sign of the control surface is positive, otherwise it is negative; the C4 control surface deflects towards the C3 control surface, the sign of the control surface is positive, otherwise it is negative; the C8 control surface deflects towards the C1 control surface, the sign of the control surface is positive, otherwise it is negative; the C6 control surface deflects towards the C7 control surface, the sign of the control surface is positive, otherwise it is negative.

[0280] As shown in the accompanying drawings, a tail stand type unmanned aerial vehicle fixed point hovering control method based on control surface vector distribution is provided, and the specific steps are as follows: Figure 1

[0281] Step one: determining the total position control amount of the control surface by using the distance between the current position of the unmanned aerial vehicle and the target position of the fixed point hovering, and the speed of the unmanned aerial vehicle approaching the target position of the fixed point hovering, and the specific steps are as follows:

[0282] Step S11. Establishing a ground reference coordinate system;

[0283] Step S12. Calculating the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system;

[0284] Step S13. Calculating the distance between the current position of the unmanned aerial vehicle and the target position of the fixed point hovering;

[0285] Step S14. Calculating the speed of the unmanned aerial vehicle approaching the target position of the fixed point hovering;

[0286] Step S15. Calculating the total position control amount of the control surface.

[0287] Further, in the step S11, the ground reference coordinate system is established, including: taking the target position of the fixed point hovering as the coordinate origin O, the geographical north direction as the positive direction of the coordinate axis OX, the geographical east direction as the positive direction of the coordinate axis OY, and OZ being perpendicular to the OXY plane and pointing to the center of the earth as the positive direction.

[0288] Further, in the step S12, the calculation formula of the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system is:

[0289]

[0290] Wherein, (X, Y, Z) is the coordinate value of the current position of the unmanned aerial vehicle in the ground reference coordinate system, R is the average radius of the earth's equator, e is the earth's flattening, H p is the current height of the unmanned aerial vehicle, H o ​is the target altitude for fixed-point hovering, LON p is the longitude of the current position of the drone, LAT p is the latitude of the current position of the drone, LON o is the longitude of the target position for fixed hovering, LAT o The latitude of the target position for fixed-point hovering.

[0291] Furthermore, in step S13, the method for calculating the distance between the current position of the drone and the fixed hovering target position is:

[0292]

[0293] Among them, ΔL is the distance between the current position of the UAV and the fixed hovering target position.

[0294] Furthermore, in step S14, the speed of the drone approaching the fixed hovering target position is the projection of the drone's current eastward speed and northward speed on the line connecting the drone's current position to the fixed hovering target position, and the specific calculation method is:

[0295]

[0296] Among them, V N is the current northbound speed of the UAV, V E is the current eastward speed of the UAV, V L V is the speed at which the UAV approaches the fixed hovering target position. N and V E Can be measured by airborne navigation equipment.

[0297] Furthermore, in step S15, the total position control amount of the control surface is calculated by a position controller, and the position controller is composed of a position control loop and a speed control loop.

[0298] Furthermore, the position control loop adopts a proportional control plus integral control structure of the distance ΔL between the current position of the drone and the fixed hovering target position, specifically:

[0299]

[0300] Among them, K L is the position control proportional term control parameter, K IL is the position control integral term control parameter, It is the speed control target for the UAV to approach the fixed hovering target position.

[0301] Furthermore, the speed control loop adopts an integral control structure of the speed error and uses the speed as the damping term, specifically:

[0302]

[0303] wherein K V is a velocity control damping term control parameter, K IV is a velocity control integral term control parameter, δ L is a total control amount of the rudder surface.

[0304] Step two: determining the position control amount of each rudder surface of the UAV by using the azimuth relationship between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the coordinate axis of the UAV body, the specific steps are as follows:

[0305] Step S21. Calculating the azimuth angle of the line connecting the current position of the UAV to the target position of the fixed-point hovering.

[0306] Step S22. Calculating the azimuth angle difference between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the coordinate axis of the UAV body.

[0307] Step S23. Distributing the total position control amount of the rudder surface to each rudder surface of the UAV by vector distribution.

[0308] Further, in the step S21, the azimuth angle of the line connecting the current position of the UAV to the target position of the fixed-point hovering is defined as the included angle between the vector pointing from the current position of the UAV to the target position of the fixed-point hovering and the geographical north, and the vector is rotated eastward from the geographical north, and the sign of the azimuth angle is positive, otherwise it is negative, and the numerical range of the azimuth angle is [-180°, 180°]. The specific calculation method of the azimuth angle is as follows:

[0309]

[0310] wherein, is the azimuth angle of the line connecting the current position of the UAV to the target position of the fixed-point hovering.

[0311] Further, in the step S22, the calculation method of the azimuth angle difference between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the coordinate axis of the UAV body is as follows:

[0312]

[0313] wherein, is the azimuth angle difference between the line connecting the current position of the UAV to the target position of the fixed-point hovering and the coordinate axis of the UAV body, and the numerical range is [-180°, 180°]. is the azimuth angle of the coordinate axis of the UAV body, which is defined as the included angle between the O p Z p axis of the UAV body coordinate system and the geographical north, that is, the yaw angle, which is measured by the on-board attitude sensor, The value range of the phase is [-180°, 180°].

[0314] Further, the step S23 is a method for distributing the total position control amount of the rudder surfaces, and comprises the following steps:

[0315]

[0316]

[0317]

[0318]

[0319] wherein, is the position control amount of the first rudder surface, is the position control amount of the second rudder surface, is the position control amount of the third rudder surface, is the position control amount of the fourth rudder surface, is the position control amount of the fifth rudder surface, is the position control amount of the sixth rudder surface, is the position control amount of the seventh rudder surface, is the position control amount of the eighth rudder surface.

[0320] Step three: determining the engine throttle control command by using the height difference between the current height of the UAV and the target height of the point hovering and the skyward speed of the UAV, and the specific steps are as follows:

[0321] Step S31. Designing a UAV height control loop, and the output of the loop is a skyward speed control target;

[0322] Step S32. Based on the skyward speed control target obtained in step S31, designing a UAV skyward speed control loop, and the output of the loop is an engine throttle control command.

[0323] Further, in step S31, the UAV height control loop adopts a proportional control structure of the height difference, and specifically:

[0324]

[0325] wherein, K H is a height control proportional term control parameter, H is the current height of the UAV, and H g is the target height of the point hovering, is the skyward speed control target.

[0326] Further, in step S32, the UAV skyward speed control loop adopts a proportional control plus integral control structure of the skyward speed and the error of the skyward speed control target, and specifically:

[0327]

[0328] wherein, is a proportional term control parameter of the skyward velocity control, is an integral term control parameter of the skyward velocity control, is the skyward velocity of the UAV, T is the engine throttle control command.

[0329] Step four: determining the direction control amount of each rudder surface of the UAV according to the target direction of the body coordinate axis of the UAV, the specific steps being:

[0330] Step S41. Designing a UAV direction controller, the output of the loop being the total direction control amount of the rudder surface;

[0331] Step S42. According to the rudder surface distribution strategy, distributing the total direction control amount of the rudder surface to each rudder surface of the UAV.

[0332] Further, in the step S41, the UAV direction controller adopts a proportional control plus integral control structure of the difference between the yaw angle and the yaw angle target, specifically:

[0333]

[0334] wherein, is a proportional term control parameter of the yaw angle target control, is an integral term control parameter of the yaw angle target control, is the yaw angle, is the yaw angle target, is the total direction control amount of the rudder surface.

[0335] Further, in the step S42, the distribution method of the total direction control amount of the rudder surface is:

[0336]

[0337]

[0338] wherein, is the direction control amount of the No. 1 rudder surface, is the direction control amount of the No. 2 rudder surface, is the direction control amount of the No. 3 rudder surface, is the direction control amount of the No. 4 rudder surface, is the direction control amount of the No. 5 rudder surface, is the direction control amount of the No. 6 rudder surface, is the direction control amount of the No. 7 rudder surface, is the direction control amount of the No. 8 rudder surface.

[0339] Step five: according to the position control amount, direction control amount of each rudder surface, calculate the control amount of each rudder surface, specifically:

[0340]

[0341]

[0342]

[0343]

[0344]

[0345]

[0346]

[0347]

[0348] Wherein, δ C1 is the control amount of the first rudder surface, δ C2 is the control amount of the second rudder surface, δ C3 is the control amount of the third rudder surface, δ C4 is the control amount of the fourth rudder surface, δ C5 is the control amount of the fifth rudder surface, δ C6 is the control amount of the sixth rudder surface, δ C7 is the control amount of the seventh rudder surface, δ C8 is the control amount of the eighth rudder surface.

[0349] The above is only the preferred embodiment of the present application, and does not hinder the application in any form, any simple modification, equivalent change of the above embodiment according to the technical essence of the present application, falls within the scope of the present application.

Claims

1. A method for controlling a tail-mounted UAV's fixed-point hovering based on rudder vector allocation, characterized by: The steps include: Step 1: Determine the total position control value of the control surface using the distance between the current position of the UAV and the fixed hovering target position and the speed at which the UAV approaches the fixed hovering target position; Step 2: Determine the position control amount of each control surface of the UAV by using the azimuth relationship between the line connecting the UAV's current position to the fixed hovering target position and the UAV's body coordinate axis; Step 3: Determine the engine throttle control command using the altitude difference between the current altitude of the drone and the fixed hovering target altitude, and the celestial speed of the drone; Step 4: Determine the directional control amount of each rudder surface of the UAV according to the target direction of the UAV body coordinate axis; Step 5: Calculate the control amount of each rudder surface based on the position control amount and direction control amount of each rudder surface; The specific steps of step one are: Step S11. Establishing a ground reference coordinate system; Step S12: Calculate the coordinate value of the current position of the UAV in the ground reference coordinate system; Step S13: Calculate the distance between the current position of the drone and the fixed hovering target position; Step S14: Calculate the speed of the UAV approaching the fixed hovering target position; Step S15. Calculate the total position control amount of the control surface; The specific steps of step 2 are: Step S21: Calculate the azimuth of the line connecting the current position of the UAV and the fixed hovering target position; Step S22: Establishing a body coordinate system; Step S23: Calculate the azimuth difference between the line connecting the current position of the UAV and the fixed hovering target position and the coordinate axis of the UAV body; Step S24: Allocate the total control amount of the control surface position to each control surface of the UAV through vector allocation; The specific steps of step three are: Step S31. Design a UAV altitude control loop, the output of which is the celestial velocity control target; Step S32. Based on the azimuth speed control target obtained in step S31, design a azimuth speed control loop for the UAV, the output of which is the engine throttle control command; Step 4 The specific steps are: Step S41. Design the UAV directional controller, where the output of the loop is the total directional control value of the rudder; Step S42: Allocate the total directional control amount of the rudder to each rudder of the UAV according to the rudder allocation strategy.

2. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 1, characterized in that: In step S11, establishing a ground reference coordinate system includes: The coordinate origin is the fixed hovering target position , geographic north is the coordinate axis The positive direction of the axis, the geographic east is the coordinate axis The positive direction of the axis, Axis perpendicular to The positive direction is flat and points towards the center of the earth.

3. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 2, characterized in that: In step S12, the coordinate values ​​of the current position of the drone in the ground reference coordinate system are as follows: in, is the coordinate value of the current position of the UAV in the ground reference coordinate system, is the mean equatorial radius of the Earth, is the Earth's oblateness, is the current altitude of the drone, is the target height for fixed-point hovering, is the longitude of the current position of the UAV, is the latitude of the current position of the UAV, is the longitude of the fixed hovering target position, The latitude of the target position for fixed-point hovering.

4. The method for controlling a tail-mounted UAV fixed-point hovering based on rudder vector allocation according to claim 3, characterized in that: In step S13, the method for calculating the distance between the current position of the drone and the fixed hovering target position is: in, The distance between the current position of the UAV and the fixed hovering target position.

5. The method for controlling a tail-mounted UAV fixed-point hovering based on rudder vector allocation according to claim 4, characterized in that: In step S14, the speed of the drone approaching the fixed hovering target position is the projection of the drone's current eastward speed and northward speed on the line connecting the drone's current position to the fixed hovering target position. The specific calculation method is: in, is the current northbound speed of the UAV, is the current eastward speed of the UAV, is the speed at which the UAV approaches the fixed hovering target position, and Can be measured by airborne navigation equipment.

6. The method for controlling a tail-mounted UAV fixed-point hovering based on rudder vector allocation according to claim 5, characterized in that: In step S15, the total position control amount of the control surface is calculated by the position controller, and the position controller is composed of a position control loop and a speed control loop for the UAV to approach the fixed hovering target position.

7. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 6, characterized in that: The position control loop uses the distance between the current position of the drone and the fixed hovering target position The proportional control plus integral control structure is as follows: in, is the position control proportional term control parameter, is the position control integral term control parameter, It is the speed control target for the UAV to approach the fixed hovering target position.

8. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 7, characterized in that: The speed control loop of the UAV approaching the fixed-point hovering target position adopts an integral control structure of the error between the speed of the UAV approaching the fixed-point hovering target position and the speed control target of the UAV approaching the fixed-point hovering target position, and uses the speed of the UAV approaching the fixed-point hovering target position as the damping term, specifically: in, is the speed control damping parameter of the UAV approaching the fixed hovering target position, is the integral control parameter of the speed control of the UAV approaching the fixed hovering target position, is the total position control quantity of the rudder surface.

9. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 8, characterized in that: In step S21, the azimuth angle of the line connecting the current position of the drone to the fixed hovering target position is defined as: the angle between the vector from the current position of the drone to the fixed hovering target position and the geographic north direction, and starting from the geographic north direction, the azimuth angle sign is positive when the vector rotates eastward, otherwise it is negative, and the value range of the azimuth angle is , the specific calculation method of the azimuth angle is: in, It is the azimuth of the line connecting the current position of the UAV to the fixed hovering target position.

10. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 9, characterized in that: In step S22, establishing the body coordinate system includes: Aircraft center of gravity is the coordinate origin; the center of the propeller or the center of the engine tail nozzle is the coordinate origin The connection line is Axis, and pointing in the direction of the nose is positive; The axis is perpendicular to the longitudinal symmetry plane of the fuselage and points towards the right wing; The axes are determined according to the right-hand rule.

11. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 10, characterized in that: The method for calculating the azimuth angle difference between the line connecting the current position of the drone to the fixed hovering target position and the coordinate axis of the drone body in step S23 is: in, It is the azimuth difference between the line connecting the current position of the UAV to the fixed hovering target position and the coordinate axis of the UAV body, and its value range is , is the azimuth of the drone body coordinate axis, defined as: drone body coordinate system The angle between the axis and the geographic north, also known as the yaw angle, is measured by the onboard attitude sensor. The numerical range is .

12. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 11, characterized in that: In step S24, the total position control amount of the rudder surface is distributed in a corresponding manner according to the layout of the rudder surface of the UAV. The specific characteristics of the rudder surface layout include: the number of the UAV rudder surfaces and the distribution position of the rudder surfaces in the duct.

13. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 12, characterized in that: Tail-seat UAV rudder layout form A: The UAV has 4 rudders, which are evenly distributed radially around the center of the duct. That is, the angle between the rotation axes of any two adjacent rudders is 90°, and the rotation axes of two of the rudders are in the body coordinate system. In the plane, and The control surface on the negative axis is marked as control surface A1. Looking from the tail to the nose, the remaining control surfaces are marked as control surface A2, A3, and A4 in a counterclockwise direction. Symbols of the control surfaces in layout A: When looking from the tail to the nose, the control surface A1 is When the axis deflects in the negative direction, the sign of the rudder is positive, otherwise it is negative; the sign of the rudder A3 is positive. When the axis deflects in the negative direction, the sign of the rudder is positive, otherwise it is negative; the sign of the rudder A2 is positive. When the axis deflects in the positive direction, the sign of the rudder is positive, otherwise it is negative; the sign of the rudder A4 is positive. The sign of the rudder surface is positive when the axis deflects in the positive direction, otherwise it is negative; For layout form A, the method of allocating the total control amount of the control surface to each control surface of the UAV is: in, is the position control value of the No. 1 rudder surface, is the position control value of the No. 2 rudder surface, is the position control value of the No. 3 rudder surface, It is the position control value of the No. 4 control surface.

14. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 12, characterized in that: The tail-seat UAV rudder layout form B is: the number of the UAV rudders is 6, and they are evenly distributed radially around the center of the duct, that is, the angle between the rotation axes of any two adjacent rudders is 60°, and the rotation axes of two of the rudders are in the body coordinate system. In the plane, and The control surface on the negative axis is marked as control surface B1. Looking from the tail to the nose, the remaining control surfaces are marked in the counterclockwise direction as control surface B2, B3, B4, B5, and B6. Symbols of the control surfaces in layout B: When looking from the tail to the nose, the control surface B1 is When the axis deflects in the negative direction, the sign of the rudder is positive, otherwise it is negative; the sign of the rudder B4 is positive. When the axis deflects in the negative direction, the sign of the rudder surface is positive, otherwise it is negative; when the B2 rudder surface deflects towards the B1 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the B3 rudder surface deflects towards the B2 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the B5 rudder surface deflects towards the B6 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the B6 rudder surface deflects towards the B1 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; For the drone rudder with layout B, the method of allocating the total rudder position control amount to each rudder surface of the drone is: in, is the position control value of the No. 1 rudder surface, is the position control value of the No. 2 rudder surface, is the position control value of the No. 3 rudder surface, is the position control value of the No. 4 rudder surface, is the position control value of the No. 5 rudder surface, It is the position control value of the No. 6 control surface.

15. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 12, characterized in that: Tail-seat UAV rudder layout form C: The UAV has 8 rudders, which are evenly distributed radially around the center of the duct. That is, the angle between the rotation axes of any two adjacent rudders is 45°, and the rotation axes of two of the rudders are in the body coordinate system. In the plane, and The rudder surface on the negative axis is marked as C1. Looking from the tail to the nose, the remaining rudder surfaces are marked in counterclockwise order as C2, C3, C4, C5, C6, C7, and C8. Symbols of the control surfaces in layout C: When looking from the tail to the nose, the C1 control surface is When the axis deflects in the negative direction, the rudder sign is positive, otherwise it is negative; the C5 rudder sign is When the axis deflects in the negative direction, the sign of the rudder is positive, otherwise it is negative; the sign of the C3 rudder is positive. When the axis deflects in the positive direction, the sign of the rudder is positive, otherwise it is negative; the C7 rudder When the axis deflects in the positive direction, the sign of the rudder surface is positive, otherwise it is negative; when the C2 rudder surface deflects towards the C1 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the C4 rudder surface deflects towards the C3 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the C8 rudder surface deflects towards the C1 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; when the C6 rudder surface deflects towards the C7 rudder surface, the sign of the rudder surface is positive, otherwise it is negative; For the UAV control surface layout C, the method of allocating the total control amount of the control surface to each control surface of the UAV is: in, is the position control value of the No. 1 rudder surface, is the position control value of the No. 2 rudder surface, is the position control value of the No. 3 rudder surface, is the position control value of the No. 4 rudder surface, is the position control value of the No. 5 rudder surface, is the position control value of the No. 6 rudder surface, is the position control value of the No. 7 rudder surface, It is the position control value of the No. 8 rudder surface.

16. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 15, characterized in that: In step S31, the UAV altitude control loop adopts a proportional control structure of altitude difference, specifically: in, is the height control proportional term control parameter, is the current altitude of the drone, is the target height for fixed-point hovering, It is the target for celestial speed control.

17. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 16, characterized in that: In step S32, the UAV tachometer speed control loop adopts a proportional control plus integral control structure of the tachometer speed and the tachometer speed control target error, specifically: in, is the control parameter of the celestial velocity proportional term, is the control parameter of the integral term of the celestial velocity control, is the celestial speed of the UAV, It is the engine throttle control command.

18. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 17, characterized in that: In step S41, the UAV direction controller adopts a proportional control plus integral control structure of the difference between the yaw angle and the yaw angle target, specifically: in, is the proportional control parameter for the yaw angle target control, is the integral control parameter for yaw angle target control, is the yaw angle, is the yaw angle target, is the total directional control quantity of the rudder surface.

19. The method for controlling a tail-mounted UAV fixed-point hovering based on rudder vector allocation according to claim 18, characterized in that: In step S42, if the drone's control surfaces are in layout A, the method for allocating the total control amount of the control surfaces to each control surface of the drone is as follows: in, is the directional control value of the No. 1 control surface, is the direction control value of the No. 2 rudder surface, is the directional control value of the No. 3 rudder surface, It is the directional control value of the No. 4 control surface.

20. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 18, characterized in that: In step S42, if the drone's control surfaces are in layout B, the method for allocating the total control amount of the control surfaces to each control surface of the drone is as follows: in, is the directional control value of the No. 1 control surface, is the directional control value of the No. 2 rudder surface, is the directional control value of the No. 3 rudder surface, is the directional control value of the No. 4 rudder surface, is the directional control value of the No. 5 rudder surface, It is the directional control value of the No. 6 control surface.

21. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 18, characterized in that: In step S42, if the drone's control surfaces are in layout form C, the method for allocating the total control amount of the control surfaces to each control surface of the drone is as follows: in, is the directional control value of the No. 1 control surface, is the directional control value of the No. 2 rudder surface, is the directional control value of the No. 3 rudder surface, is the directional control value of the No. 4 rudder surface, is the directional control value of the No. 5 rudder surface, is the directional control value of the No. 6 rudder surface, is the direction control value of the No. 7 rudder surface, It is the directional control value of the No. 8 control surface.

22. The method for controlling a tail-mounted UAV fixed-point hovering based on rudder vector allocation according to claim 19, characterized in that: The step five is specifically as follows: The control surfaces of the UAV are in layout A. The calculation method of the control amount of each control surface is: in, is the control amount of the No. 1 rudder surface, is the control amount of the No. 2 rudder surface, is the control amount of the No. 3 rudder surface, It is the control amount of the No. 4 rudder surface.

23. The method for controlling a tail-mounted UAV fixed-point hovering based on rudder vector allocation according to claim 20, characterized in that: The step five is specifically as follows: The control surface of the UAV is in layout B, and the calculation method of the control amount of each control surface is: in, is the control amount of the No. 1 rudder surface, is the control amount of the No. 2 rudder surface, is the control amount of the No. 3 rudder surface, is the control amount of the No. 4 rudder surface, is the control amount of the No. 5 rudder surface, It is the control amount of the No. 6 rudder surface.

24. The method for controlling a tail-seat UAV fixed-point hovering based on rudder vector allocation according to claim 21, characterized in that: The step five is specifically as follows: The control surfaces of the UAV are in layout form C, and the calculation method of the control amount of each control surface is: in, is the control amount of the No. 1 rudder surface, is the control amount of the No. 2 rudder surface, is the control amount of the No. 3 rudder surface, is the control amount of the No. 4 rudder surface, is the control amount of the No. 5 rudder surface, is the control amount of the No. 6 rudder surface, is the control amount of the No. 7 rudder surface, It is the control amount of the No. 8 rudder surface.

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