A deformable drone and method of controlling the same

Abstract

The application discloses a deformable unmanned aerial vehicle and a control method thereof, which comprises a body and four rotating wing mechanisms fixed on the body, one end of the rotating wing mechanism is hinged to the body, and the other end is provided with a propeller mechanism; the body is provided with a sliding block limiting mechanism for driving the four rotating wing mechanisms to rotate synchronously, and the sliding block limiting mechanism is used for driving the four rotating wing mechanisms to be folded inward synchronously. The control method steps S1-S5 are further included. The deformable unmanned aerial vehicle can adapt to various complex flight environment conditions, has good flexibility and maneuverability, adopts a mechanism principle similar to an umbrella, and designs rotors that can move up and down to adapt to different flight environments, so that various flight tasks can be better completed. The deformable unmanned aerial vehicle can automatically deform, autonomously plan a path and automatically navigate, and is a four-rotor variable mechanism unmanned aerial vehicle, so that efficient self-adaptive flight of the unmanned aerial vehicle in a complex environment is realized.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more particularly to a deformable unmanned aerial vehicle and its control method. Background Technology

[0002] Unmanned vehicles can be used for military or civilian applications such as surveillance, reconnaissance, and exploration. They can be equipped with functional payloads, such as sensors for collecting environmental data. For example, remotely controlled unmanned aerial vehicles, including fixed-wing and rotary-wing aircraft, can provide aerial imagery of environments otherwise inaccessible.

[0003] Traditional quadcopter drones mostly adopt the classic X-shaped quadcopter design, which rigidly connects the drone body to the motor and propeller mechanism through linkages. Traditional quadcopter drones can maintain good stability, but the drone rotor is in a fixed state, which makes the overall size of the drone too large. It cannot be well adapted to a variety of complex working environments. Often, the large size of its rotor makes it unable to work by overcoming obstacles, thus limiting its flight environment. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a deformable unmanned aerial vehicle (UAV) and its control method.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] A deformable unmanned aerial vehicle (UAV) and its control method are provided, including a body and four rotor mechanisms fixed on the body. One end of the rotor mechanism is hinged to the body, and the other end is provided with a propeller mechanism. A slider limiting mechanism is provided on the body to drive the four rotor mechanisms to rotate synchronously. The slider limiting mechanism is used to drive the four rotor mechanisms to retract inward synchronously.

[0007] Furthermore, each rotor mechanism includes two upper connecting rods, two lower connecting rods, and a linkage member. The two upper connecting rods are fixedly connected to form an upper support arm, and the two lower connecting rods are fixedly connected to form a lower support arm. One end of the upper support arm and the lower support arm are connected by a motor nacelle support frame, which is used to install the propeller mechanism. The other end of the upper support arm is hinged to the fuselage via a fourth pin, and the other end of the lower support arm is hinged to the fuselage via a second pin. One end of the linkage member is hinged to the lower support arm via a first pin, and the other end is hinged to the slider limiting mechanism via a third pin.

[0008] Furthermore, the two upper connecting rods are fixedly connected by two first reinforcing connecting plates, and the two lower connecting rods are fixedly connected by two second reinforcing connecting plates.

[0009] Furthermore, the propeller mechanism includes a motor, a propeller, and a barrel-shaped motor nacelle. The propeller is fixed to the output end of the motor, the motor is fixed inside the motor nacelle, and the motor nacelle is fixedly connected to the rotor mechanism by two first bolts and two second bolts.

[0010] Furthermore, the fuselage includes an upper top plate and a bottom support plate. The upper top plate and the bottom support plate are fixedly connected by four positioning columns. There are also eight structural support columns between the upper top plate and the bottom support plate. Every two structural support columns are used to rotatably connect the rotor mechanism. The structural support columns are hinged to the rotor mechanism. Two frame legs are fixed to the bottom of the bottom support plate.

[0011] Furthermore, a middle partition is fixed to the bottom of the four structural support columns, which is used to limit the slider limiting mechanism.

[0012] Furthermore, the slider limiting mechanism includes a cross-shaped central slider and a slider electric cylinder that drives the central slider to move vertically. The four ends of the central slider are all hinged to the rotor mechanism, and the four ends of the central slider are all provided with guide holes. The bottom of the slider electric cylinder is fixed to the body, and the telescopic end of the slider electric cylinder is fixedly connected to the central slider.

[0013] Furthermore, it also includes a control system, which includes a power module, a flight control module, a GPS module, a 3D depth recognition camera, a UAV dynamics module, and a motor drive module. The power module is electrically connected to the flight control module, and the GPS module, the 3D depth recognition camera, the UAV dynamics module, and the motor drive module are all electrically connected to the flight control module. The 3D depth recognition camera is located at the bottom of the fuselage.

[0014] A control method for a deformable unmanned aerial vehicle includes the following steps:

[0015] S1: Before the flight mission begins, set the initial position of the UAV and the initial position of the destination in the flight control module, and use the flight control module to set the flight path and flight altitude; the initial position includes longitude and latitude, upper and lower limits of flight altitude during the flight process, upper limit of flight speed, and longitude, latitude and altitude of the destination;

[0016] S2: After the flight mission begins, the motors start working, the drone ascends to the set flight altitude, and then flies to the location above the destination coordinates; during the flight, the 3D depth recognition camera identifies the area in front of the drone, and the flight control module controls whether the drone automatically avoids obstacles and passes through them;

[0017] S3: After reaching the destination coordinates, the UAV performs coordinate calibration. Once it confirms that its own position coordinates are consistent with the set destination coordinates, it hovers at the set target altitude to carry out the flight mission.

[0018] S4: After completing the mission at the destination, the drone returns to base; specifically:

[0019] S41: Swap the initial position coordinates of the UAV and the initial position coordinates of the destination set in step S1, and start the return mission, as in step S2.

[0020] S42: After returning to the initial position coordinates of the drone, the slider electric cylinder starts to work, putting the drone into the unfolded posture;

[0021] S43: The 3D depth recognition camera identifies obstacles during the descent. If no obstacle is detected below the drone, it descends slowly at the lowest speed. If no obstacle is detected below the drone, the landing position coordinates are changed to avoid obstacles.

[0022] S44: After landing, the motor stops working, the slider electric cylinder returns to its initial state, and the four rotor mechanisms return to their initial state;

[0023] S5: Repeat steps S1-S4 to complete the next flight mission.

[0024] Furthermore, in step S2, the UAV uses a 3D depth recognition camera in conjunction with the flight control module to achieve obstacle avoidance and detour as follows:

[0025] S21: Establish a three-dimensional spatial coordinate system with the centroid of the deformable UAV as the origin;

[0026] S22: The 3D depth recognition camera captures images of the front of the drone frame by frame, and the flight control module judges obstacles in the captured images;

[0027] S23: The flight control module selects between normal flight or proceeding to the next step based on the proportion of obstacles in the left and right anchor frames;

[0028] S24: The flight control module selects hovering mode or automatic obstacle avoidance based on the proportion of obstacles on the left and right sides to the area of ​​the anchor frame. If automatic obstacle avoidance is selected, proceed to the next step.

[0029] S25: The flight control module adjusts the thrust control constant of several propellers according to the proportion of the left and right anchor frames to achieve obstacle avoidance.

[0030] The beneficial effects of this invention are as follows:

[0031] The deformable drone of the present invention can change the horizontal position of the rotor and the overall size of the drone according to the working environment during the operation of the drone. While maintaining stability, it has good flexibility and maneuverability and is suitable for a variety of different working environments.

[0032] The deformable UAV of this invention can adapt to a variety of complex flight environments and has good maneuverability. It adopts a mechanism similar to an umbrella and is designed with rotors that can move up and down to adapt to different flight environments and better complete various flight missions.

[0033] Compared with traditional quadcopter drones, this invention features a simpler mechanical structure, lower production costs, and suitability for various flight environments. It is a highly mobile, flexible, and maneuverable quadcopter drone. Utilizing the mechanism principle of an umbrella, the rotor is modified into a movable form, and a central movable connecting plate is added, resembling the frame of an umbrella.

[0034] This invention relates to a quadcopter variable-mechanism unmanned robot capable of automatic transformation, autonomous path planning, and automatic navigation, enabling efficient adaptive flight in complex environments. Traditional quadcopter drones often employ the classic X-shaped quadcopter design, rigidly connecting the drone's fuselage to the motors and propellers via linkages. While this design maintains good stability, it also results in a relatively large overall size. It performs well in open areas but is limited in complex and changing environments. Therefore, based on this reason and drawing inspiration from traditional quadcopter design, this invention adopts an umbrella-like mechanism, designing the four rotors to be movable. The four rotors can move upwards and downwards according to the working environment, changing the overall size of the drone and improving its maneuverability and flexibility, allowing it to adapt to different flight environments and mission requirements. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of the deformable UAV of the present invention. Figure 1 ;

[0036] Figure 2 This is a schematic diagram of the overall structure of the deformable UAV of the present invention. Figure 2 ;

[0037] Figure 3 This is a schematic diagram of the deformable UAV of the present invention with the control system removed;

[0038] Figure 4 A schematic diagram of the rotor mechanism and propeller mechanism;

[0039] Figure 5 Schematic diagram of the slider limiting mechanism and the machine body Figure 1 ;

[0040] Figure 6 Schematic diagram of the slider limiting mechanism and the machine body Figure 2 ;

[0041] Figure 7This is a structural diagram of the rotor mechanism, propeller mechanism, slider limiting mechanism, and fuselage.

[0042] Figure 8 for Figure 7 A magnified view of a section at point A in the middle;

[0043] Figure 9 This is a schematic diagram showing the distribution of the four propellers;

[0044] Figure 10 A flowchart illustrating the propeller control process for drones to avoid obstacles.

[0045] The symbols for the main components in the diagram are explained below:

[0046] 1. Rotor mechanism; 11. Upper connecting rod; 12. Lower connecting rod; 13. Linkage rod; 14. Motor nacelle support frame; 15. First reinforcing connecting plate; 16. Second reinforcing connecting plate; 17. First pin; 18. Second pin; 19. Third pin; 10. Fourth pin;

[0047] 2. Propeller mechanism; 21. Propeller; 22. Engine compartment; 23. Motor; 24. First bolt; 25. Second bolt;

[0048] 3. Body; 31. Top plate; 32. Positioning column; 33. Bottom support plate; 34. Intermediate partition plate; 35. Structural support column; 36. Frame legs;

[0049] 4. Slider limiting mechanism; 41. Center slider; 42. Slider electric cylinder;

[0050] 5. Control system; 51. 3D depth recognition camera. Detailed Implementation

[0051] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0052] like Figure 1 , 2 As shown in Figure 3, the deformable drone includes a body 3 and four rotor mechanisms 1 fixed to the body 3. Each rotor mechanism 1 is hinged to the body 3 at one end and has a propeller mechanism 2 at the other end. The body 3 is provided with a slider limiting mechanism 4 that drives the four rotor mechanisms 1 to rotate synchronously. The slider limiting mechanism 4 is used to drive the four rotor mechanisms 1 to retract inward synchronously, making the drone's shape slender and easier to pass through narrow airspace with obstacles.

[0053] like Figure 4 As shown, the rotor mechanism 1 includes two parallel upper connecting rods 11, two parallel lower connecting rods 12, and a linkage rod 13. The two parallel upper connecting rods 11 are fixedly connected to form an upper support arm, and the two parallel lower connecting rods 12 are fixedly connected to form a lower support arm. One end of the upper and lower support arms is connected by a motor nacelle support frame 14, which is used to install the propeller mechanism 2. The other end of the upper support arm is hinged to the fuselage 3 by a fourth pin 10, and the other end of the lower support arm is hinged to the fuselage 3 by a second pin 18. One end of the linkage rod 13 is hinged to the lower support arm by a first pin 17, and the other end is hinged to the slider limiting mechanism 4 by a third pin 19. The two linkage rods 13 connect the movement of the rotor with the slider limiting mechanism 4. The movement of the linkage rods 13 is controlled by the slider limiting mechanism 4, thereby controlling the synchronous up and down movement of the four rotor mechanisms 1. In this embodiment, each rotor mechanism 1 is equipped with two linkage rods 13, each linkage rod 13 is hinged to a connecting rod 12, and the two linkage rods 13 forcefully connect the rotor mechanism 1 and the slider limiting mechanism 4. The rotor mechanism 1 adopts a double parallel linkage connection method to ensure the stability of the motor placement location, and the propeller direction is always vertically upward. The two pairs of parallel linkages are cleverly connected by a hollowed-out support plate, which reduces the overall weight of the UAV and allows the shaft part to evenly distribute the force when subjected to external force, thereby improving the structural strength and stability of the UAV. The two upper connecting rods 11 are fixedly connected by two first reinforcing connecting plates 15, and the two lower connecting rods 12 are fixedly connected by two second reinforcing connecting plates 6. The first reinforcing connecting plates 15 and 6 ensure the structural strength and motion stability of the rotor and improve the structural rigidity of the rotor. The specific working principle is as follows: one end of the upper connecting rod 11 and the lower connecting rod 12 is hinged to the body 3, and one end of the linkage rod 13 is hinged to the lower connecting rod 12. By controlling the slider limiting mechanism 4 to move up and down, the far end of the four rotor mechanisms 1 is driven to retract inward, thereby changing the shape of the UAV body, making the UAV body slender and easier to pass through narrow obstacle airspace.

[0054] The propeller mechanism 2 includes a motor 23, a propeller 21, and a barrel-shaped motor housing 22. The propeller 21 is fixed to the output end of the motor 23, and the motor 23 is fixed inside the motor housing 22. The motor housing 22 is fixedly connected to the rotor mechanism 1 by two first bolts 24 and two second bolts 25. The rotor mechanism 1 adopts a double parallel linkage connection method to ensure the stability of the motor placement, and the propeller direction is always vertically upward. The two pairs of parallel linkages are cleverly connected by a hollowed-out support plate, which reduces the overall weight of the UAV and allows the shaft part to evenly distribute the force when subjected to external forces, thereby improving the structural strength and stability of the UAV.

[0055] like Figure 5 and 6As shown, the fuselage 3 includes an upper top plate 31 and a bottom support plate 33. The upper top plate 31 and the bottom support plate 33 are fixedly connected by four positioning posts 32. Eight structural support columns 35 are also provided between the upper top plate 31 and the bottom support plate 33. Each pair of structural support columns 35 is used to rotatably connect the rotor mechanism 1. The structural support columns 35 are hinged to the rotor mechanism 1. The structural support columns 35 are provided with an upper hinge hole that mates with the fourth pin 10 and a lower hinge hole that mates with the second pin 18. Two frame legs 36 are fixed to the bottom of the bottom support plate 33. A middle partition 34 is fixed to the bottom of the four structural support columns 35. The middle partition 34 is used to limit the slider limiting mechanism 4. The fuselage 3 is divided into upper and lower layers. The upper layer houses key control components such as the flight control module, CNC board, and GPS module. The lower layer is the core area for structural deformation. In this core area, the slider limiting mechanism 4 can move up and down according to a specific constrained track, realizing rapid deformation and adjustment of the UAV structure.

[0056] like Figure 7 and 8 As shown, the slider limiting mechanism 4 includes a cross-shaped central slider 41 and a slider electric cylinder 42 that drives the central slider 41 to move vertically. All four ends of the central slider 41 are hinged to the rotor mechanism 1. Each of the four ends of the central slider 41 has a guide hole that mates with the positioning post 32. The bottom of the slider electric cylinder 42 is fixed to the body 1, and the telescopic end of the slider electric cylinder 42 is fixedly connected to the central slider 41. The specific working principle is as follows: the telescopic end of the slider electric cylinder 42 drives the central slider 41 to slide up and down. Under the guidance of the positioning post 32, the central slider 41 drives the linkage rods 13 on the four rotor mechanisms 1 to move up and down. This, in turn, uses the linkage rods 13 to rotate the lower support arm of the rotor mechanism 1, thereby achieving the inward retraction of the four rotor mechanisms 1. To ensure the quadcopters remain on the same horizontal plane throughout their movement and maintain the stability of the UAV, a slider limiting mechanism 4 is designed. The positioning pin 32 determines the trajectory of the central slider 41. It is connected to the four rotor mechanisms via pins, and the reciprocating motion of the four rotor mechanisms is controlled by the slider electric cylinder 42, allowing the four rotor mechanisms to move up and down within their stroke range. Simultaneously, the upper top plate 31 and the middle partition plate 34 restrict the upper and lower limits of the central slider 41's movement, ensuring it remains within the correct range of motion.

[0057] The system also includes a control system 5, which comprises a power supply module, a flight control module, a GPS module, a 3D depth recognition camera 51, a UAV dynamics module, and a motor drive module. The power supply module is electrically connected to the flight control module. The GPS module, the 3D depth recognition camera 51, the UAV dynamics module, and the motor drive module are all electrically connected to the flight control module. The 3D depth recognition camera 51 is located at the bottom of the fuselage 1. The flight control module preferably has a display screen, such as a Ledi OSD module. The UAV dynamics module is responsible for calculating and updating various key information of the UAV based on the input forces and torques, including position, velocity, attitude, and angular velocity. When the UAV is subjected to external forces, this module receives the data of the external forces and then combines it with the physical properties of the UAV to calculate the motion state of the UAV under these forces. In addition, the control system includes a position controller and an attitude controller. The main task of the position controller is to ensure that the UAV can move accurately and stably to the designated position. The attitude controller consists of two parts: an inner loop that controls angular velocity and an outer loop that controls angle. This strategy ensures that the UAV can respond stably and accurately to operational commands, whether hovering, cruising, or performing complex maneuvers. The GPS module provides the UAV's latitude and longitude information, the visual acquisition and analysis module is responsible for obstacle avoidance during flight, and the flight control module is the core of the UAV's control system. All information is collected here and fed back to the UAV to formulate a response plan.

[0058] The control method for deformable unmanned aerial vehicles includes the following steps:

[0059] S1: Before the flight mission begins, set the initial position of the UAV and the initial position of the destination in the flight control module, and use the flight control module to set the flight path and flight altitude; the initial position includes longitude and latitude, upper and lower limits of flight altitude during the flight process, upper limit of flight speed, and longitude, latitude and altitude of the destination;

[0060] S2: After the flight mission begins, motor 23 starts working, and the drone ascends to the set flight altitude, then flies above the destination coordinates. The flight control module displays the drone's flight coordinates, speed, altitude, and other flight parameters in real time on the map. During flight, the 3D depth recognition camera 51 identifies the area in front of the drone, and the flight control module controls whether the drone automatically avoids obstacles. The identification work specifically includes acquiring images, processing the images into a grid, and mapping them into a 3D space grid. This part is existing technology and will not be elaborated here. The specific principle of the drone's automatic obstacle avoidance is as follows: the location of obstacles in the anchor frame to be identified and the location of the obstacles in front are marked to obtain the relative position data between the drone and the obstacle. The position information is transmitted to the control system, and the side with fewer obstacles is selected to control motor 23 to move in the x or y axis direction. For example, if there are too many obstacles on the right, the power of the two motors 23 on the right is increased, the two propellers on the right gain more lift, and the drone moves to the left. Under normal circumstances, no movement in the z axis direction is performed to avoid obstacles. If there are too many obstacles in the anchor frame and autonomous obstacle avoidance is not possible, a hovering command is issued, and the drone waits for the operator to take over.

[0061] S3: After reaching the destination coordinates, the UAV performs coordinate calibration. Once it confirms that its own position coordinates are consistent with the set destination coordinates, it hovers at the set target altitude to carry out the flight mission.

[0062] S4: After completing the mission at the destination, the drone returns to base; specifically:

[0063] S41: Swap the coordinates of the initial position of the drone and the initial position of the destination set in step S1, and start the return mission. The process is the same as in step S2. Specifically, the drone rises to the set flight altitude corresponding to the initial position of the destination, and then flies to the set flight altitude corresponding to the initial position of the drone.

[0064] S42: After returning to the initial position coordinates of the drone, the slider cylinder 42 starts to work, controlling the four rotor mechanisms 1 to unfold, so that the drone is in an unfolded posture, forming a shape similar to an umbrella.

[0065] S43: The 3D depth recognition camera 51 detects whether there are obstacles during the descent. If no obstacle is detected below the drone, it will descend slowly at the lowest speed. If no obstacle is detected below the drone, it will change the landing position coordinates to avoid obstacles.

[0066] S44: After landing, motor 23 stops working, slider electric cylinder 42 returns to its initial state, and four-rotor mechanism 1 returns to its initial state;

[0067] S5: Repeat steps S1-S4 to complete the next flight mission;

[0068] The method for the UAV to achieve obstacle avoidance and detour in step S2 is as follows:

[0069] S21: Establish a three-dimensional coordinate system with the centroid of the deformable UAV as the origin; specifically, the direction facing the 3D recognition camera is the positive x-axis, the right side of the 3D recognition camera is the positive y-axis, and the top of the UAV is the positive z-axis.

[0070] S22: The 3D depth recognition camera 51 acquires images of the front of the drone frame by frame, and the flight control module judges obstacles from the acquired images; in this invention, the detection distance of the 3D depth recognition camera 51 is 15 meters.

[0071] S23: The flight control module selects between normal flight or proceeding to the next step based on the proportion of obstacles in the left and right anchor frames; specifically: during flight, the 3D depth recognition camera 51 detects obstacles directly in front (positive x-axis direction in the figure) frame by frame, dividing the left and right sides of the image recognition anchor frame into two regions, α and β, with obstacle area proportions A and B in regions α and β, respectively; the control flow is as follows: Figure 10 Specifically:

[0072] If A≥10%S or B≥10%S, where S is the area of ​​the entire image recognition anchor frame region, the flight control module determines that obstacle avoidance is required and controls the slider cylinder 42 to move, changing the drone to a folded state and proceeding to the next step.

[0073] If A < 10%S or B < 10%S, the UAV will continue to fly normally without changing its flight attitude.

[0074] S24: The flight control module selects between hovering mode and automatic obstacle avoidance based on the proportion of obstacles on the left and right sides to the anchor frame area. If automatic obstacle avoidance is selected, it proceeds to the next step. Specifically:

[0075] If A+B≥75%S, the UAV enters hover mode and sends a signal to the flight control system, waiting for the operator to take over. If there are obstacles only in the α or β region, obstacle avoidance is required. In this case, the values ​​of k2 and k3 are adjusted simultaneously to increase the thrust of the propeller 2 and propeller 3 motors, causing the UAV to move in the positive y-axis direction until the 3D depth recognition camera 51 recognizes that the area of ​​the obstacle in front meets A<10%S or B<10%S. At this time, the thrust of the propeller 2 and propeller 3 motors returns to normal flight speed, and normal flight is resumed.

[0076] If A+B<75%S, and obstacles are detected in both regions α and β, then compare the sizes of A and B and proceed to the next step.

[0077] S25: The flight control module adjusts the thrust control constants k1, k2, k3, and k4 of propeller 1, propeller 2, propeller 3, and propeller 4 based on the values ​​of A and B to achieve obstacle avoidance; specifically:

[0078] If A≥B, then k2 and k3 values ​​are adjusted synchronously to increase the thrust of propeller 2 and propeller 3 motors, so that the UAV moves a distance in the positive y-axis direction until the three-dimensional depth recognition camera 51 recognizes that the area ratio of the obstacle in front meets A<10%S or B<10%S. At this time, the thrust of propeller 2 and propeller 3 motors returns to normal flight speed, and normal flight is carried out.

[0079] If A < B, then k1 and k4 values ​​are adjusted synchronously to increase the thrust of propeller 1 and propeller 4 motors, causing the UAV to move a distance in the negative Y-axis direction until the 3D depth recognition camera 51 recognizes that the area ratio of the obstacle in front meets A < 10%S or B < 10%S. At this time, the thrust of propeller 1 and propeller 4 motors returns to normal flight speed, and normal flight is carried out.

[0080] In this control method, the thrust magnitude control constant k corresponding to the propeller is combined with the motor power value distribution model to perform power control distribution on the four motors: the deformable UAV adopts an X-shaped frame, such as... Figure 9 The motor power value allocation model adopted is as follows:

[0081]

[0082] Where F1 is the output thrust of the motor corresponding to propeller 1, F2 is the output thrust of the motor corresponding to propeller 2, F3 is the output thrust of the motor corresponding to propeller 3, and F4 is the output thrust of the motor corresponding to propeller 4; f d Input thrust value to the system base; θ and φ are both Euler angles. Let θ be the yaw angle on the x-axis, θ be the roll angle on the y-axis, and φ be the pitch angle on the z-axis, while θ pwm φ pwm , The analog signals representing yaw, roll, and pitch angles in the control system; k1, k2, k3, and k4 are the propeller thrust control constants, ranging from 0 to 1000; pwm baseThe baseline value for the analog signal is 1000. Therefore, in the control system, the output thrust of the four propellers is controlled by adjusting the k values ​​corresponding to the four propellers. For example, if the selected motor has a maximum speed of 10,000 RPM, and the drone starts at 0 RPM and gradually increases to 5,000 RPM, then k1, k2, k3, and k4 are all adjusted to 500, and the power of all four motors is at 50%, achieving a hovering state. During normal flight, k2 and k4 are 700, while k1 and k3 remain unchanged, and the drone flies forward. Move forward; when obstacle avoidance is needed, set the k value to 850 and the motor output power to 85%. If obstacle avoidance is needed on the α side, increase the k2 and k3 values ​​to 850 to increase the propeller output thrust, and adjust the k1 and k4 values ​​to 500 to reduce the propeller output thrust on that side. The drone moves to the β side. The drone's maximum k value is set to 950 and the motor output power to 95%, at which point it obtains maximum power. After reaching the target location, k1, k2, k3, and k4 are all adjusted to 500 to achieve a hovering state, and then gradually descend to 0, at which point the drone lands.

[0083] Specifically, the thrust and torque generated by the propeller rotation satisfy the following relationship with the propeller speed:

[0084]

[0085] Where f is the total thrust generated by the four propellers, τ x , τ y , τ z The propellers are respectively in

[0086] The torque generated on the x, y, and z axes; c T c is the propeller thrust coefficient. M d is the propeller torque coefficient; d is the distance from the fuselage to any motor, and the distances from the four motors to the fuselage are equal. These are the angular velocities corresponding to propellers 1, 2, 3, and 4, respectively.

[0087] The position and attitude changes of the UAV during flight are specifically controlled through a UAV position and attitude dynamics model. The rotation sequence of the UAV is defined as follows: first around the z-axis of the UAV, then around the y-axis, and finally around the x-axis. The specific UAV position and attitude dynamics model is as follows:

[0088]

[0089]

[0090] in, R is the overall rotation matrix of the UAV; R(φ) is the sub-rotation matrix for rotation φ around axis x; R(θ) is the sub-rotation matrix for rotation θ around axis y. Rotation about axis z Sub-rotation matrix.

Claims

1. A deformable drone, characterized in that, The utility model provides a kind of unmanned aerial vehicle, including body (3) and four rotors (1) fixed on body (3), each rotors (1) is hinged with body (3) at one end, and the other end is provided with propeller mechanism (2); The body (3) is provided with sliding block limiting mechanism (4) for driving four rotors (1) to rotate synchronously, and the sliding block limiting mechanism (4) is used to drive four rotors (1) to fold inward synchronously; The rotors (1) include two upper connecting rods (11), two lower connecting rods (12) and linkage rod (13), two upper connecting rods (11) are fixedly connected to form upper support arms, two lower connecting rods (12) are fixedly connected to form lower support arms, one end of the upper support arms and the lower support arms is connected by motor compartment support frame (14), the motor compartment support frame (14) is used to install propeller mechanism (2), the other end of the upper support arms is hinged with the body (3) by the fourth pin shaft (10), the other end of the lower support arms is hinged with the body (3) by the second pin shaft (18), one end of the linkage rod (13) is hinged with the lower support arms by the first pin shaft (17), and the other end is hinged with the sliding block limiting mechanism (4) by the third pin shaft (19); The body (3) includes upper top plate (31) and bottom support plate (33), the upper top plate (31) and the bottom support plate (33) are fixedly connected by four positioning columns (32), eight structural columns (35) are further arranged between the upper top plate (31) and the bottom support plate (33), each two structural columns (35) are used to rotatably connect the rotors (1), and the structural columns (35) are hinged with the rotors (1); two rack legs (36) are fixed to the bottom of the bottom support plate (33); The sliding block limiting mechanism (4) includes cross-shaped center sliding block (41) and sliding block electric cylinder (42) for driving the center sliding block (41) to move vertically, four side ends of the center sliding block (41) are hinged with the rotors (1), the four side ends of the center sliding block (41) are provided with guide holes, the bottom of the sliding block electric cylinder (42) is fixed on the body (3), and the telescopic end of the sliding block electric cylinder (42) is fixedly connected with the center sliding block (41); Further comprising a control system (5), the control system (5) includes a power module, a flight control module, a GPS module, a three-dimensional depth recognition camera (51), a UAV dynamics module and a motor drive module, the power module is electrically connected with the flight control module, the GPS module, the three-dimensional depth recognition camera (51), the UAV dynamics module and the motor drive module are all electrically connected with the flight control module, and the three-dimensional depth recognition camera (51) is arranged at the bottom of the body (3).

2. The morphing drone of claim 1, wherein, Two upper connecting rods (11) are fixedly connected by two first reinforcing connecting plates (15), and two lower connecting rods (12) are fixedly connected by two second reinforcing connecting plates (6).

3. The morphing drone of claim 1, wherein, The propeller mechanism (2) comprises a motor (23), a propeller (21) and a barrel-shaped motor cabin (22), the propeller (21) is fixed at the output end of the motor (23), the motor (23) is fixed in the motor cabin (22), and the motor cabin (22) is fixedly connected with the rotor mechanism (1) through two first bolts (24) and two second bolts (25).

4. The morphing drone of claim 1, wherein, The bottom of the eight structure support columns (35) is fixed with an intermediate partition plate (34), and the intermediate partition plate (34) is used for limiting the sliding block limiting mechanism (4).

5. A control method for the morphing drone of any one of claims 1-4, characterized in that, The method comprises the following steps: S1: before the flight task starts, the initial position of the unmanned aerial vehicle and the initial position of the destination are set in the flight control module, and the flight path and the flight height are set by using the flight control module; S2: after the flight task starts, the motor (23) starts to work, the unmanned aerial vehicle rises to the set flight height, and then flies to above the destination coordinate; in the flight process, the three-dimensional depth recognition camera (51) recognizes the front of the unmanned aerial vehicle, and the flight control module controls whether the unmanned aerial vehicle automatically avoids obstacles and rounds; S3: after reaching the destination coordinate, the unmanned aerial vehicle performs coordinate calibration, and after confirming that the self-position coordinate is consistent with the set destination coordinate, the unmanned aerial vehicle hovers at the set target height to perform the flight task; S4: after the unmanned aerial vehicle completes the task at the destination, the unmanned aerial vehicle returns; specifically: S41: the initial position of the unmanned aerial vehicle and the initial position of the destination set in step S1 are exchanged, and the return task starts, and the process is as shown in step S2; S42: after returning to the initial position of the unmanned aerial vehicle, the sliding block cylinder (42) starts to work, so that the unmanned aerial vehicle is in an unfolded posture; S43: the three-dimensional depth recognition camera (51) recognizes whether there is an obstacle in the landing process downward, if no obstacle is recognized below the unmanned aerial vehicle, the unmanned aerial vehicle slowly lands at the lowest speed; if an obstacle is recognized below the unmanned aerial vehicle, the landing position coordinate is changed to avoid the obstacle; S44: after landing, the motor (23) stops working, the sliding block cylinder (42) returns to the initial state, and the four rotor mechanisms (1) return to the initial state; S5: steps S1-S4 are repeated to complete the next flight task.

6. The method of claim 5, wherein, In step S2, the unmanned aerial vehicle realizes obstacle avoidance and rounding by the three-dimensional depth recognition camera (51) and the flight control module as follows: S21: taking the center of mass of the deformable unmanned aerial vehicle as a coordinate origin, a three-dimensional coordinate system is established; S22: the three-dimensional depth recognition camera (51) frame by frame collects images in front of the unmanned aerial vehicle, and the flight control module judges obstacles in the collected images; S23: the flight control module selects normal flight or the next step according to the proportion of obstacles in the left and right anchor frames; S24: the flight control module selects hovering mode or automatic obstacle avoidance and rounding according to the proportion of obstacles in the left and right anchor frames, and selects automatic obstacle avoidance and rounding to perform the next step; S25: the flight control module adjusts the thrust size control constant of a plurality of propellers according to the proportion of the left and right anchor frames, so as to realize obstacle avoidance and rounding.

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