Centroid and distributed power high wind resistant fixed wing unmanned aerial vehicle and control method thereof

Abstract

The application belongs to the technical field of unmanned aerial vehicle research, and discloses a high-wind-resistance fixed-wing unmanned aerial vehicle with variable center of mass and distributed power and a control method thereof. The high-wind-resistance fixed-wing unmanned aerial vehicle comprises a fuselage, wings and a tail wing; a distributed power cabin is arranged on the upper surface of the wing along the wingspan direction; a power battery pack is arranged in the fuselage cabin of the fuselage, and the position of the power battery pack is changed through a variable center of mass assembly. The control method measures the flight attitude and sideslip angle information in real time through a flight control system control module, compares the information with the set attitude and wind speed threshold, and controls the heading through the differential compound of the distributed power arranged on the wing, so that the stability and maneuverability requirements of the aerial vehicle in the complex crosswind environment are met, and the high-wind-resistance purpose is achieved. The high-wind-resistance fixed-wing unmanned aerial vehicle and the control method thereof adopt the variable center of mass assembly which has simple structure and reliable action; the position of the power battery pack accounting for 20% to 30% of the total weight of the aircraft is adjusted to control the center of mass, and the application has engineering practical value.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle research technology, specifically relating to a high wind-resistant fixed-wing unmanned aerial vehicle with variable center of mass and distributed power, and its control method. Background Technology

[0002] The need to strike a balance between stability and maneuverability in aircraft design limits their usability in complex crosswind environments.

[0003] In recent years, electric fixed-wing drone technology has developed rapidly and has been widely used in both civilian and military fields. However, due to their small size and light weight, electric fixed-wing drones are highly susceptible to crosswinds when taking off, landing, or operating in low-altitude environments. This crosswinds can generate significant adverse sideslip angles, leading to large yaw moments that cause attitude instability, which in turn limits takeoff and landing or prevents the completion of missions.

[0004] To mitigate the degradation of flight quality caused by disturbances in unstable flow fields such as gusts when electric fixed-wing UAVs encounter gusts, a common approach is to achieve stability by designing an appropriate distance between the aerodynamic center and the center of mass, allowing the UAV to return to its original state after being disturbed. However, insufficient stability makes the flight attitude prone to change, hindering precise control; while excessively long distances between the aerodynamic center and the center of mass result in greater stability, reducing controllability and minimizing unfavorable sideslip angles.

[0005] The Chinese Patent Document Database discloses a hovering folding-wing lifting body aircraft based on variable center of mass technology (CN103963959A). This hovering folding-wing lifting body aircraft adjusts its center of mass position by moving a mass block embedded in a sliding track, thereby meeting the requirements for multi-attitude flight performance. However, the aforementioned sliding mass block is only for adjusting the center of mass position during the deformation process of the hovering folding-wing lifting body aircraft, and does not consider actively participating in wind resistance. Furthermore, the addition of the mass block not only increases the structural weight but also reduces flight performance.

[0006] Currently, there is an urgent need to develop a high wind-resistant fixed-wing UAV with a variable center of mass and distributed propulsion, as well as its control method. Summary of the Invention

[0007] One technical problem to be solved by the present invention is to provide a high wind-resistant fixed-wing UAV with a variable center of mass and distributed propulsion. Another technical problem to be solved by the present invention is to provide a control method for a high wind-resistant fixed-wing UAV with a variable center of mass and distributed propulsion, so as to overcome the defects of the prior art.

[0008] The high wind-resistant fixed-wing UAV with variable center of mass and distributed propulsion of the present invention includes a fuselage, wings, and a tail. A distributed propulsion nacelle is installed on the upper surface of the wings along the wingspan direction. Each wing's distributed propulsion nacelle includes 12 parallel ducted fans, with 6 ducted fans forming a group. The ducted fans are arranged in groups 1 to 4 from left to right on the wings, and are controlled according to the grouping. A power battery pack is installed in the fuselage compartment, and the power battery pack is installed in the variable center of mass assembly. The power battery pack includes several batteries arranged in an array. The variable center of mass assembly includes a first bulkhead, a second bulkhead, and a third bulkhead, which are fixed sequentially from front to back inside the fuselage compartment. Four parallel slide rails are fixed between the second and third bulkheads. The power battery pack is installed inside the power battery compartment, and the power battery compartment is mounted on the slide rails by a slider. A push rod is fixed to the front face of the power battery compartment, and the push rod is housed in a barrel-shaped cam; the barrel-shaped cam connects the servo motor and the brake; The servo motor and brake receive signals from the flight control system. When it is necessary to change the center of gravity of the high wind-resistant fixed-wing UAV, the brake is unlocked, the servo motor drives the barrel cam to rotate, and the push rod, driven by the barrel cam, drives the power battery compartment to reciprocate along the slide rail. When the center of gravity is adjusted to the required position, the servo motor stops, the brake is locked, and the process of changing the center of gravity of the high wind-resistant fixed-wing UAV is completed.

[0009] Furthermore, the rear end of the push rod is inserted into the front end face of the power battery compartment and fixed to the front end face of the power battery compartment with a nut.

[0010] Furthermore, a cylindrical key perpendicular to the central axis of the push rod is fixed at the front end of the push rod; the barrel-shaped cam includes an inner cylinder and an outer cylinder that are connected by an insertion joint, the cylindrical key of the push rod is installed in the spiral groove of the inner cylinder, and the outer cylinder is connected to a servo motor and a brake in sequence; the servo motor drives the outer cylinder to move the push rod in the spiral groove of the inner cylinder, and at the same time pulls the power battery compartment to reciprocate along the slide rail.

[0011] The control method for a high wind-resistant fixed-wing UAV with variable center of mass and distributed dynamics of the present invention includes the following processes: S10. When the high-wind-resistant fixed-wing UAV is in a stable flow field and its center of mass remains unchanged, the high-wind-resistant fixed-wing UAV maintains attitude stability through its own flight stability. At this time, the high-wind-resistant fixed-wing UAV uses the rudder and power differential to jointly control the heading angle. The rudder control law is: ; In the formula, For sideslip angle tracking error, This is the sideslip angle reference signal. Sideslip angle; Yaw angular velocity; For sideslip angle control parameters, The integral control parameter for the sideslip angle error is... These are the yaw rate control parameters; This refers to the rudder deflection angle; S20. When in a crosswind environment with winds not exceeding level 6, the center of mass is in the initial position closest to the nose. At this time, the high wind-resistant fixed-wing UAV uses the rudder to control the heading angle. S30. When in a crosswind environment exceeding level 6, the position of the power battery compartment of the variable center of mass component is determined by the crosswind speed, and the stability of the high wind-resistant fixed-wing UAV changes with the position of the power battery compartment; when the power battery compartment reaches its maximum stroke, the stability of the high wind-resistant fixed-wing UAV is at its minimum, and the power differential control efficiency is at its maximum; the control process is as follows: For right-side winds, the control laws for the power differential and the position of the power battery compartment are as follows: ; In the formula, For the first i Input power of ducted fans, For the incoming flow velocity, The angle between the incoming flow and the longitudinal axis of the aircraft is defined as the direction of the incoming flow being to the right of the longitudinal axis. In this configuration, Mode 1 is without differential operation; Mode 2 uses 100% power for the first and second ducted fans H1 and H2, and 70% power for the third and fourth ducted fans H3 and H4; Mode 3 uses 100% power for the first and second ducted fans H1 and H2, and 50% power for the third and fourth ducted fans H4; X represents the position of the battery compartment, where X=X0 indicates the battery compartment is closest to the nose, and X=X... max This indicates that the battery compartment is located furthest from the nose of the aircraft. For left-side winds, the power distribution of the duct fans in groups 1 through 4 is opposite, while the position control law of the power battery compartment is the same.

[0012] The variable center of mass and distributed power high wind-resistant fixed-wing UAV and its control method of the present invention adopt a simple variable center of mass component structure and reliable operation; the center of mass is controlled by adjusting the position of the power battery pack, which accounts for 20% to 30% of the total weight of the aircraft, resulting in high control efficiency.

[0013] The variable center of mass and distributed power high wind-resistant fixed-wing UAV and its control method of the present invention measure the flight attitude and sideslip angle information in real time through the flight control system control module and compare it with the set attitude and wind speed thresholds. The distributed power differential compound arranged on the wing is used for heading control. The relationship between the ducted fan power, the position of the variable center of mass mechanism and the rudder angle under different crosswind magnitudes is given. When the above relationship is satisfied, a good wind resistance effect is achieved, realizing strong wind resistance capability during flight.

[0014] In summary, the variable center of mass and distributed power high wind-resistant fixed-wing UAV and its control method of the present invention meet the stability and maneuverability requirements of the aircraft in complex crosswind environments through variable center of mass and power differential composite control, and achieve the purpose of high wind resistance, which has practical engineering value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the high wind-resistant fixed-wing UAV with variable center of mass and distributed power according to the present invention. Figure 2 This is a schematic diagram of the variable center of mass component in the high wind-resistant fixed-wing UAV with variable center of mass and distributed power according to the present invention. Figure 3 This is a schematic diagram of the barrel cam-push rod structure in the high wind-resistant fixed-wing UAV with variable center of mass and distributed dynamics of the present invention. Figure 4 This is a schematic diagram illustrating the principle of the variable center of mass and distributed power high wind-resistant fixed-wing UAV and its control method of the present invention.

[0016] In the image, 1. fuselage; 2. wing; 3. tail; 4. distributed power nacelle; 5. battery pack; 6. variable center of mass assembly; 601. First partition frame; 602. Second partition frame; 603. Third partition frame; 604. Slide rail; 605. Power battery compartment; 606. Slider; 607. Servo motor; 608. Brake; 609. Battery; 610. Nut; 611. Outer cylinder; 612. Push rod; 613. Cylindrical key; 614. Inner cylinder. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] Example: Figures 1-3As shown, the high wind-resistant fixed-wing UAV with variable center of mass and distributed power in this embodiment includes a fuselage 1, wings 2, and a tail 3; a distributed power nacelle 4 is installed on the upper surface of the wingspan, and each distributed power nacelle 4 of the wings 2 includes 12 parallel ducted fans, with 6 ducted fans forming a group; the ducted fans on the wings 2 are arranged from left to right as group 1 to group 4, and the ducted fans are controlled according to the group; a power battery pack 5 is installed in the fuselage compartment of the fuselage 1, and the power battery pack 5 is installed in the variable center of mass assembly 6; the power battery pack 5 includes several batteries 609 arranged in an array; The variable center of mass assembly 6 includes a first bulkhead 601, a second bulkhead 602, and a third bulkhead 603, which are fixed sequentially from front to back inside the fuselage compartment of the fuselage 1; four parallel slide rails 604 are fixed between the second bulkhead 602 and the third bulkhead 603; the power battery pack 5 is installed in the inner cavity of the power battery compartment 605; the power battery compartment 605 is mounted on the slide rails 604 by a slider 606. A push rod 612 is fixed to the front end of the power battery compartment 605, and the push rod 612 is housed in a barrel-shaped cam; the barrel-shaped cam connects the servo motor 607 and the brake 608; Servo motor 607 and brake 608 receive signals from the flight control system. When it is necessary to change the center of gravity of the high wind-resistant fixed-wing UAV, brake 608 is unlocked, servo motor 607 drives barrel cam to rotate, and push rod 612, driven by barrel cam, drives power battery compartment 605 to reciprocate along slide rail 604. When the center of gravity is adjusted to the required position, servo motor 607 stops rotating, brake 608 is locked, and the process of changing the center of gravity of the high wind-resistant fixed-wing UAV is completed.

[0019] Furthermore, the rear end of the push rod 612 is inserted into the front end face of the power battery compartment 605 and fixed to the front end face of the power battery compartment 605 by a nut 610.

[0020] Furthermore, a cylindrical key 613 perpendicular to the central axis of the push rod 612 is fixed at the front end of the push rod 612; the barrel-shaped cam includes an inner cylinder 614 and an outer cylinder 611 that are connected by an insertion joint, the cylindrical key 613 of the push rod 612 is installed in the spiral groove of the inner cylinder 614, and the outer cylinder 611 is connected in sequence to a servo motor 607 and a brake 608; the servo motor 607 drives the outer cylinder 611 to drive the push rod 612 to move in the spiral groove of the inner cylinder 614, and at the same time pulls the power battery compartment 605 to reciprocate along the slide rail 604.

[0021] The control method for a high wind-resistant fixed-wing UAV with a variable center of mass and distributed dynamics in this embodiment includes the following processes: S10. When the high-wind-resistant fixed-wing UAV is in a stable flow field and its center of mass remains unchanged, the high-wind-resistant fixed-wing UAV maintains attitude stability through its own flight stability. At this time, the high-wind-resistant fixed-wing UAV uses the rudder and power differential to jointly control the heading angle. The rudder control law is: ; In the formula, For sideslip angle tracking error, This is the sideslip angle reference signal. Sideslip angle; Yaw angular velocity; For sideslip angle control parameters, The integral control parameter for the sideslip angle error is... These are the yaw rate control parameters; This refers to the rudder deflection angle; S20. When in a crosswind environment with winds not exceeding level 6, the center of mass is in the initial position closest to the nose. At this time, the high wind-resistant fixed-wing UAV uses the rudder to control the heading angle. S30. When in a crosswind environment exceeding level 6, the position of the power battery compartment 605 of the variable center of mass component 6 is determined by the crosswind speed, and the stability of the high wind-resistant fixed-wing UAV changes with the position of the power battery compartment 605; when the power battery compartment 605 reaches its maximum stroke, the stability of the high wind-resistant fixed-wing UAV is at its minimum, and the power differential control efficiency is at its maximum; the control process is as follows: For right-side winds, the control laws for the power differential and the 605 position of the power battery compartment are as follows: ; In the formula, For the first i Input power of ducted fans, For the incoming flow velocity, The angle between the incoming flow and the longitudinal axis of the aircraft is defined as the direction of the incoming flow being to the right of the longitudinal axis. like Figure 4 As shown, Mode 1 is without differential operation; Mode 2 uses 100% power for the first group of ducted fans H1 and the second group of ducted fans H2, and 70% power for the third group of ducted fans H3 and the fourth group of ducted fans H4; Mode 3 uses 100% power for the first group of ducted fans H1 and the second group of ducted fans H2, and 50% power for the third group of ducted fans H3 and the fourth group of ducted fans H4; X represents the position of the power battery compartment 605, X=X0 indicates that the power battery compartment 605 is closest to the nose, X=X max This indicates that the power battery compartment 605 is located furthest from the nose of the engine; For left-side winds, the power distribution of the duct fans in groups 1 to 4 is opposite, while the position control law of the power battery compartment 605 is the same.

[0022] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. For those skilled in the art, all features disclosed in the present invention, or all steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way without departing from the principles of the present invention. The present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A control method for a high-wind-resistant fixed-wing UAV with variable center of mass and distributed propulsion, characterized in that, The aforementioned high wind-resistant fixed-wing UAV with variable center of mass and distributed power includes a fuselage (1), wings (2) and tail (3); a distributed power pod (4) is installed on the upper surface of the wings (2) along the wingspan direction, and each wing (2)'s distributed power pod (4) includes 12 parallel ducted fans, with 6 ducted fans forming a group; the wing (2) is arranged from left to right as the 1st to the 4th group, and the ducted fans are controlled according to the group; a power battery pack (5) is installed in the fuselage compartment of the fuselage (1), and the power battery pack (5) is installed in the variable center of mass assembly (6); the power battery pack (5) includes several batteries (609) arranged in an array. The variable center of mass assembly (6) includes a first bulkhead (601), a second bulkhead (602) and a third bulkhead (603) that are fixed in sequence from front to back inside the fuselage compartment of the fuselage (1); four parallel slide rails (604) are fixed between the second bulkhead (602) and the third bulkhead (603); the power battery pack (5) is installed in the inner cavity of the power battery compartment (605); the power battery compartment (605) is mounted on the slide rails (604) by a slider (606); A push rod (612) is fixed to the front end of the power battery compartment (605), and the push rod (612) is housed in a barrel-shaped cam; the barrel-shaped cam connects the servo motor (607) and the brake (608). The servo motor (607) and brake (608) receive signals from the flight control system. When it is necessary to change the center of gravity of the high wind-resistant fixed-wing UAV, the brake (608) is unlocked, the servo motor (607) drives the barrel cam to rotate, and the push rod (612) drives the power battery compartment (605) to reciprocate along the slide rail (604) under the push of the barrel cam. When the center of gravity is adjusted to the required position, the servo motor (607) stops rotating, the brake (608) locks, and the process of changing the center of gravity of the high wind-resistant fixed-wing UAV is completed. The control method includes the following processes: S10. When the high-wind-resistant fixed-wing UAV is in a stable flow field and its center of mass remains unchanged, the high-wind-resistant fixed-wing UAV maintains attitude stability through its own flight stability. At this time, the high-wind-resistant fixed-wing UAV uses the rudder and power differential to jointly control the heading angle. The rudder control law is: ； In the formula, For sideslip angle tracking error, This is the sideslip angle reference signal. Sideslip angle; Yaw angular velocity; For sideslip angle control parameters, The integral control parameter for the sideslip angle error is... These are the yaw rate control parameters; This refers to the rudder deflection angle; S20. When in a crosswind environment with winds not exceeding level 6, the center of mass is in the initial position closest to the nose. At this time, the high wind-resistant fixed-wing UAV uses the rudder to control the heading angle. S30. When in a crosswind environment exceeding level 6, the position of the power battery compartment (605) of the variable center of mass component (6) is determined by the crosswind speed, and the stability of the high wind-resistant fixed-wing UAV changes with the position of the power battery compartment (605); when the power battery compartment (605) reaches its maximum stroke, the stability of the high wind-resistant fixed-wing UAV is at its minimum, and the power differential control efficiency is at its maximum; the control process is as follows: For right-side winds, the position control laws for the power differential and the power battery compartment (605) are as follows: ； In the formula, For the first i Input power of ducted fans, For the incoming flow velocity, The angle between the incoming flow and the longitudinal axis of the aircraft is defined as the direction of the incoming flow being to the right of the longitudinal axis. Among them, mode 1 is no differential; mode 2 is that the first group of ducted fans H1 and the second group of ducted fans H2 use 100% power, and the third group of ducted fans H3 and the fourth group of ducted fans H4 use 70% power; mode 3 is that the first group of ducted fans H1 and the second group of ducted fans H2 use 100% power, and the third group of ducted fans H3 and the fourth group of ducted fans H4 use 50% power; X is the position of the power battery compartment (605), X=X0 indicates that the power battery compartment (605) is closest to the nose, X=X max This indicates that the power battery compartment (605) is located furthest from the nose of the engine; For left-side winds, the power distribution of the duct fans in groups 1 to 4 is opposite, while the position control law of the power battery compartment (605) is the same.

2. The control method for a high-wind-resistant fixed-wing UAV with variable center of mass and distributed dynamics according to claim 1, characterized in that, The rear end of the push rod (612) is inserted into the front end face of the power battery compartment (605) and fixed to the front end face of the power battery compartment (605) by a nut (610).

3. The control method for a high-wind-resistant fixed-wing UAV with variable center of mass and distributed dynamics according to claim 2, characterized in that, The front end of the push rod (612) is fixed with a cylindrical key (613) perpendicular to the central axis of the push rod (612); the barrel cam includes an inner cylinder (614) and an outer cylinder (611) that are connected by an insertion. The cylindrical key (613) of the push rod (612) is installed in the spiral groove of the inner cylinder (614). The outer cylinder (611) is connected to a servo motor (607) and a brake (608) in sequence. The servo motor (607) drives the outer cylinder (611) to drive the push rod (612) to move in the spiral groove of the inner cylinder (614), and at the same time pulls the power battery compartment (605) to reciprocate along the slide rail (604).

Images