A method and system for inclined take-off and landing of a tilt-rotating quadrotor land-to-air drone

Abstract

The present invention relates to the technical field of vehicle-mounted unmanned aerial vehicle (UAV) platforms, and in particular to a method and system for inclined take-off and landing of a tilt-quadrotor land-to-air UAV, comprising: tilting the UAV; obtaining the current pitch attitude through an attitude sensor of the UAV, adjusting the tilt mechanism of the tilt-quadrotor UAV so that the rotor motor shaft is perpendicular to the horizontal plane; planning a take-off path based on position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a take-off trajectory; tracking the take-off trajectory to complete inclined take-off; determining the terminal position and tilt attitude of landing; planning a landing path based on observation constraints, position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a landing trajectory; replanning the path if the UAV observes the UAV; and completing landing after reaching the landing endpoint. The present invention can improve the safety and stability of UAVs taking off and landing on inclined surfaces.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle-mounted unmanned aerial vehicle (UAV) platforms, and in particular to a method and system for inclined plane take-off and landing of a tilt-rotating quad-rotor land-to-air UAV. Background Art

[0002] Currently, collaborative systems between drones and unmanned vehicles are very popular. Unmanned vehicles can serve as support platforms for drones, improving their overall endurance. Drones can also utilize their high-altitude vision to assist unmanned vehicle operations. Collaborative systems that allow drones to land on unmanned vehicles involve the entire process of taking off and landing the drone on the vehicle.

[0003] For vehicle-mounted drone platforms, the terrain can cause the vehicle to tilt during driving, and mainstream quadcopters exhibit coupled pitch and roll attitudes, limiting their ability to take off and land stably on a horizontal surface. This requires platform mechanisms or control methods to achieve inclined takeoff and landing. Currently, there are two main types of inclined takeoff and landing technologies. One involves installing an inclined servo plane on the unmanned vehicle, which is then leveled to a horizontal plane, enabling the drone to take off and land on the servo plane. However, this method requires the installation of a servo mechanism and support rods to ensure the servo plane's angle adjustment and stability, significantly increasing the weight and size of the unmanned vehicle and reducing its overall efficiency. Another approach involves the quadcopter executing rapid maneuvering trajectories while maintaining its attitude coordinated with the vehicle's motion during flight to achieve precise landings. However, due to the coupled attitude of the quadcopter, this method generates trajectories requiring high peak angular velocities or positional accelerations, placing high demands on the drone's maneuverability and tracking control performance. Furthermore, the drone may cause minor impacts with the vehicle during landing, reducing the system's service life. Therefore, existing unmanned vehicle-drone collaborative systems have yet to effectively address the issue of inclined takeoff and landing for drones on unmanned vehicles. Summary of the Invention

[0004] In view of the above problems, the present invention provides a tilting quad-rotor land-to-air UAV take-off and landing method and system, which solves the technical problem in the prior art that quad-rotor UAVs have difficulty taking off and landing on tilted unmanned vehicles.

[0005] On the one hand, the present invention provides a slope take-off and landing system for a tilt-quadrotor land-air drone, comprising a tilt-quadrotor drone and a ground unmanned vehicle. The tilt-quadrotor drone is provided with an attitude sensor, a perception and positioning module, and a wireless transmission module. The ground unmanned vehicle is provided with a perception and positioning module identification code at the center of the top plane, and is also provided with a wireless transmission module.

[0006] In one aspect, the present invention provides a takeoff method for a tilt-quadrotor land-to-air drone using a slope takeoff and landing system, which is used for the tilt-quadrotor drone to take off from the roof of an unmanned vehicle that is tilted to the ground, comprising the following steps:

[0007] Step S11: The unmanned vehicle adjusts its roll angle so that the roll angle is less than a preset threshold, thereby forming a tilted roof.

[0008] Step S12: The attitude sensor of the tilt-quadrotor UAV obtains the current pitch attitude, and adjusts the tilt mechanism of the tilt-quadrotor UAV based on the pitch attitude so that the rotor motor shaft is perpendicular to the horizontal plane;

[0009] Step S13: The tilt-quadrotor UAV performs takeoff path planning based on position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a takeoff trajectory;

[0010] Step S14: After receiving the take-off command, the tilt-quadrotor UAV tracks the take-off trajectory and completes the slope take-off.

[0011] Preferably, the tilt-quadrotor UAV includes four tiltable rotor mechanisms and a tilt mechanism, which can control the rotor structure to tilt around a set rotation axis and change the direction of the rotor motor shaft in the rotor mechanism; the tilt-quadrotor UAV is integrated with an attitude sensor for obtaining the pitch attitude of the tilt-quadrotor UAV in real time.

[0012] Preferably, step S13 specifically includes:

[0013] Step S13-1, setting the current position and attitude of the tilt-quadrotor UAV as the take-off starting point, and setting the designated target position and attitude as the take-off end point;

[0014] Step S13-2: Based on the takeoff starting point and takeoff end point, an initial feasible takeoff path is generated using a path planning method;

[0015] Step S13-3: Optimize the initial feasible takeoff path according to the continuity constraints of position and velocity, dynamic constraints, and safety constraints to obtain a takeoff trajectory.

[0016] Preferably, in step S13-3, the continuity constraint of the position and speed refers to setting the optimization result of the initial feasible takeoff path to a polynomial trajectory of order 5 or above;

[0017] The dynamic constraints are used to limit the range of the fuselage pitch angle, the range of the fuselage pitch angle change rate, the range of the fuselage speed, and the range of the fuselage acceleration;

[0018] The safety constraints are used to limit the distance between the fuselage position and the top plane of the unmanned vehicle and obstacles.

[0019] On the one hand, the present invention provides a landing method for a tilt-quadrotor land-to-air drone using a slope take-off and landing system, which is characterized in that the tilt-quadrotor drone is used to land on the roof of an unmanned vehicle inclined to the ground, comprising the following steps:

[0020] Step S21: The tilt-quadrotor UAV receives the position and attitude of the UAV sent by the UAV, and determines the landing end position and tilt attitude;

[0021] Step S22: The tilt-rotor quadrotor UAV performs landing path planning based on the current position and attitude, landing endpoint position and tilt attitude, observation constraints, position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a landing trajectory;

[0022] Step S23: After receiving the landing command, the tilt-quadrotor UAV tracks the landing trajectory; if the perception and positioning module onboard the tilt-quadrotor UAV observes the unmanned vehicle during the tracking process, the landing end position and tilt attitude are updated with the observed position and attitude of the unmanned vehicle, and the process returns to step S22; the landing is completed until the position and attitude of the tilt-quadrotor UAV are consistent with the end position and tilt attitude.

[0023] Preferably, step S22 specifically includes:

[0024] Step S22-1, setting the current position and attitude of the tilt-quadrotor UAV as the landing starting point, and setting the landing end position and tilt attitude as the landing end point;

[0025] Step S22-2: Based on the landing start point and landing end point, an initial feasible landing path is generated using a path planning method;

[0026] Step S22-3: Optimize the initial feasible landing path according to observation constraints, position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a landing trajectory.

[0027] Preferably, the tilt-quadrotor UAV is provided with a perception and positioning module for observing the unmanned vehicle below, and an identification code of the perception and positioning module is provided at the center position of the top plane of the unmanned vehicle.

[0028] Preferably, in step S22-3, the continuity constraint of the position and velocity refers to setting the optimization result of the initial feasible landing path to a polynomial trajectory of order 5 or above;

[0029] The observation constraint is used to limit the center of the top plane of the unmanned vehicle to be within the visual range of the perception and positioning module;

[0030] The dynamic constraints are used to limit the range of the fuselage pitch angle, the range of the fuselage pitch angle change rate, the range of the fuselage speed, and the range of the fuselage acceleration;

[0031] The safety constraints are used to limit the distance between the drone position and the top plane of the unmanned vehicle and obstacles.

[0032] Preferably, the step S23 specifically includes:

[0033] The perception and positioning module is used for real-time perception during the flight of the UAV. When the perception and positioning module recognizes the perception and positioning module identification code, it is confirmed that the unmanned vehicle is observed, the center position of the unmanned vehicle on the top plane in the observation constraint is updated, and the process returns to step S2 until the position and attitude error between the unmanned vehicle and the tilt-rotating quadrotor UAV is less than the preset threshold, and the landing is completed.

[0034] Compared with the prior art, the present invention has at least the following beneficial effects:

[0035] (1) The present invention utilizes the characteristics of decoupling control of the tilt-quadrotor UAV's posture, and can independently adjust the position and attitude, so that the UAV's blade plane is level during the slope takeoff process, and the attitude can be adjusted without affecting the position, thereby improving the safety and reliability during the slope takeoff process.

[0036] (2) During the landing process, the tilt-rotor quadcopter UAV receives the position and attitude information of the unmanned vehicle in real time and, in combination with the feedback from the onboard sensing and positioning module, replans the landing trajectory during flight. When the UAV detects a deviation in its trajectory or a change in the position of the unmanned vehicle, it replans the path until the final position and attitude are consistent with the target, thereby improving the landing accuracy and reliability and ensuring that the UAV can land safely on the tilted roof.

[0037] (3) Compared with the prior art, the present invention does not require the installation of additional servo mechanisms or support rods on the unmanned vehicle, thereby reducing the structural complexity of the unmanned vehicle and the additional energy consumption, and improving the overall efficiency of the UAV-UAV collaborative system. At the same time, the present invention utilizes the decoupling planning and control of the tilt-quadrotor UAV to enable it to execute a smoother trajectory, reducing the requirements for high-frequency response and high-precision control of the controller, improving the reliability and landing safety of the system, and enabling the UAV to complete take-off and landing tasks more efficiently and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings are only for purposes of illustrating particular embodiments and are not to be considered limiting of the invention.

[0039] Figure 1 This is a flow chart of the method for the tilt-quadrotor land-to-air drone to take off from the inclined surface of the roof of an unmanned vehicle provided by the present invention.

[0040] Figure 2 This is a flow chart of the method for the tilt-quadrotor land-to-air drone provided by the present invention to land on the inclined surface of the roof of an unmanned vehicle.

[0041] Figure 3 This is a detailed flow chart of the method for taking off and landing a tilt-quadrotor land-to-air drone on the slope of an unmanned vehicle provided by the present invention.

[0042] Figure 4 Schematic diagram of the UAV and unmanned vehicle collaborative system provided by the present invention.

[0043] Figure 5 This is a schematic diagram of the take-off trajectory of the UAV provided by the present invention.

[0044] Figure 6 This is a schematic diagram of the landing trajectory of the drone provided by the present invention.

[0045] Figure 7 This is a schematic diagram of the UAV and unmanned vehicle collaborative system example provided by the present invention and the slope takeoff trajectory and slope landing trajectory of the UAV example.

[0046] Figure 1: 1-tilt quadrotor drone, 2-perception and positioning module, 3-perception and positioning module identification code, 4-unmanned vehicle, 5-wireless transmission module, 6-drone example slope landing trajectory, 7-drone example slope takeoff trajectory. DETAILED DESCRIPTION

[0047] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. In addition, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0048] Aiming at the problem of slope takeoff and landing of UAVs on unmanned vehicles, in order to overcome the shortcomings of the existing technology, the present invention utilizes the posture decoupling characteristics of tilt-quadrotor UAVs, and aims to propose a method and system for air-to-ground slope takeoff and landing based on tilt-quadrotor UAVs, so as to improve the stability and robustness of UAVs taking off and landing on slopes on unmanned vehicles.

[0049] In order to illustrate the effectiveness of the method proposed in the present invention, the above technical solution of the present invention is described in detail below through a specific embodiment.

[0050] like Figure 4 、 Figure 7As shown, the present invention discloses a tilt-rotor quadrotor land-air UAV slope take-off and landing system, comprising a tilt-rotor quadrotor UAV and a ground unmanned vehicle, wherein the tilt-rotor quadrotor UAV is provided with an attitude sensor, a perception and positioning module 2 and a wireless transmission module 5, and the ground unmanned vehicle is provided with a perception and positioning module identification code 3 at the center position of the top plane thereof, and is also provided with a wireless transmission module 5.

[0051] The attitude sensor is used to obtain the aerial motion attitude information of the unmanned vehicle, and the sensing and positioning module 2 is used to locate the sensing and positioning module identification code 3 on the unmanned vehicle. The wireless transmission module 5 is used on the unmanned vehicle to continuously communicate and exchange information such as the position and attitude of the unmanned vehicle and the unmanned vehicle.

[0052] Figure 7 The specific example of the tilt-rotor land-air UAV and unmanned vehicle collaborative system, the typical slope landing trajectory 6 and the typical slope take-off trajectory 7 are demonstrated.

[0053] like Figure 1 As shown, the present invention also discloses a tilt-quadrotor UAV takeoff method for land-to-air slope, which is used for the tilt-quadrotor UAV to take off from the roof of an unmanned vehicle inclined to the ground. The specific implementation steps are as follows:

[0054] Step S11: The unmanned vehicle adjusts its roll angle so that the roll angle is less than a preset threshold;

[0055] The technical solution of the present invention is applied to the scenario where a UAV takes off and lands on an inclined surface on an unmanned vehicle. Before taking off, the tilt-rotating quad-rotor UAV is parked on the roof of the unmanned vehicle.

[0056] As the unmanned vehicle moves along the terrain, it adjusts its roll angle to keep it below a preset threshold. This way, the impact of the rugged terrain on the drone's attitude is concentrated on the tilt-quadcopter's pitch channel, facilitating stable takeoff.

[0057] Step S12: The attitude sensor of the tilt-quadrotor UAV obtains the current pitch attitude, and adjusts the tilt mechanism of the tilt-quadrotor UAV based on the pitch attitude so that the rotor motor shaft is perpendicular to the horizontal plane;

[0058] The tilt-quadrotor drone of the present invention includes at least four tiltable rotor mechanisms, each equipped with a rotor motor and propeller blades. The rotor mechanisms can tilt around a predetermined axis to change the orientation of the rotor motor shafts and adjust to different flight attitudes. The drone of the present invention incorporates an attitude sensor that can acquire real-time pitch attitude data.

[0059] In this step, first, the attitude sensor obtains the current pitch attitude of the drone, and then calculates the adjustment amount of the tilt mechanism based on the pitch attitude. The adjustment amount of the tilt mechanism is used to drive the tilt mechanism of the wing to make corresponding adjustments, so that the rotor motor shaft tilts to be perpendicular to the horizontal plane.

[0060] Through the above adjustments, the propeller plane of the drone can be made parallel to the horizontal plane, making the drone more stable when taking off from an inclined plane on the drone.

[0061] Step S13: The tilt-quadrotor UAV performs takeoff path planning based on position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a takeoff trajectory;

[0062] In this step, the starting point and end point of the takeoff trajectory are first determined, the current position and attitude of the drone are set as the starting point, and the specified target position and attitude are set as the end point.

[0063] Based on the start and end points of the takeoff trajectory, an initial feasible path is generated using a path planning method such as A* or RRT*. This initial feasible path is then optimized based on position and velocity continuity constraints, dynamic constraints, and safety constraints, as described below.

[0064] The polynomial trajectory of order 5 or above satisfies the continuity constraints of the drone's position and velocity, so the optimization result is set to a polynomial trajectory of order 5 or above;

[0065] The dynamic constraints include velocity limit and acceleration limit, which are expressed as:

[0066]

[0067] in for The fuselage pitch angle at the moment, represents the magnitude of a vector, Indicates any choice, is the trajectory duration, To limit the pitch angle of the tiltrotor fuselage, for The speed of the UAV in the ground coordinate system at the moment, is the speed limit of the UAV in the ground coordinate system, for The rate of change of the fuselage pitch angle at time t, is the limit of the pitch angle change rate of the tiltrotor fuselage, for The acceleration of the drone in the ground coordinate system at the moment, is the acceleration limit of the UAV in the ground coordinate system.

[0068] The safety constraint is used to avoid collision with the top plane of the unmanned vehicle and obstacles. The expression of the safety constraint is:

[0069]

[0070] Among them, the superscript In the ground coordinate system, is the normal direction of the top plane of the unmanned vehicle, represents the transpose operation, Indicates the position of the UAV in the ground coordinate system, Indicates the center position of the unmanned vehicle on the top plane, is the matrix determined by the shape of the i-th ellipsoid obstacle, is the geometric center position of the i-th ellipsoid obstacle in the ground coordinate system, is the total number of obstacles.

[0071] By optimizing the initial feasible path, the takeoff trajectory is finally obtained. Figure 5 The figure shows the take-off trajectory of the present invention. Figure 5 The takeoff target, that is, the pitch angle of the top plane of the unmanned vehicle is 45 degrees

[0072] Step S14: After receiving the take-off command, the tilt-quadrotor UAV tracks the take-off trajectory and completes the slope take-off.

[0073] In this step, the tilt-rotor quadcopter UAV unlocks and takes off after receiving the take-off command. The UAV adjusts the trajectory variables in real time by controlling To complete the tracking of the takeoff trajectory and finally complete the slope takeoff. is the three-dimensional position of the UAV in the ground coordinate system, is the yaw angle, is the pitch angle.

[0074] like Figure 2 As shown, the present invention discloses a slope landing method for a tilt-rotating quad-rotor land-to-air UAV, which is used for the tilt-rotating quad-rotor UAV to land on the roof of an unmanned vehicle inclined to the ground. The specific implementation steps are as follows:

[0075] Step S21: The tilt-quadrotor UAV receives the position and attitude of the UAV sent by the UAV, and determines the landing end position and tilt attitude;

[0076] In this step, the drone receives the position and posture of the unmanned vehicle sent by the unmanned vehicle. Based on the position and posture of the unmanned vehicle, the drone can obtain the final landing position and tilt posture of the drone through coordinate transformation and other processing as the final landing target of the drone.

[0077] Step S22: The tilt-rotor quadrotor UAV performs landing path planning based on the current position and attitude, landing endpoint position and tilt attitude, observation constraints, position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a landing trajectory;

[0078] In this step, the starting point and end point of the landing trajectory are first determined, where the starting point of the landing trajectory is the current position and attitude of the drone, and the end point is the position and attitude of the drone when it lands on the top plane of the unmanned vehicle, that is, the end point position and tilt attitude in step S1.

[0079] Based on the starting and ending points of the landing trajectory, an initial feasible path is generated using a path planning method such as A* or RRT*. Landing path planning is performed based on observation constraints, position and velocity continuity constraints, dynamic constraints, and safety constraints. The position and velocity continuity constraints, dynamic constraints, and safety constraints are identical to those in the technical solution for takeoff and are not repeated here.

[0080] like Figure 4 As shown, a tilt-quadrotor drone 1 carries a downward-looking sensing and positioning module 2 for observing an unmanned vehicle 4. A sensing and positioning module identification code 3 is provided at the center of the top plane of the unmanned vehicle. The tilt-quadrotor drone 1 can determine the three-dimensional position of the center of the top plane of the unmanned vehicle based on the sensing and positioning module identification code 3 captured by the sensing and positioning module 2.

[0081] In some embodiments, the observation constraint is based on the fact that the onboard perception and positioning module carried by the tilt-quadrotor land-air drone is a downward-looking observation camera, and the identification code of the perception and positioning module carried by the unmanned vehicle is an Apriltag identification code.

[0082] In this observation mode, the observation constraint is used to constrain the top plane of the unmanned vehicle to be within the image of the perception and positioning module. The expression is:

[0083]

[0084] in, are the three-dimensional positions of the center position on the top plane of the unmanned vehicle in the ground coordinate system, They are respectively represented as the three-dimensional position of the UAV in the ground coordinate system, In order to adjust the amount, the present invention is set to be less than half of the viewing angle of the observation camera.

[0085] By optimizing the initial feasible path, the landing trajectory is finally obtained. Figure 6 The figure shows the landing trajectory of the present invention. Figure 6 The landing target, that is, the pitch angle of the top plane of the unmanned vehicle is 35°.

[0086] Step S23: After receiving the landing command, the tilt-quadrotor UAV tracks the landing trajectory; if the onboard perception and positioning module of the tilt-quadrotor UAV observes the unmanned vehicle during the tracking process, the process returns to step S22; the landing is completed until the position and attitude of the UAV are consistent with the end position and tilt attitude.

[0087] In this step, after receiving the landing command, the tilt-quadrotor UAV tracks the landing trajectory and uses the perception and positioning module 2 to capture images in real time. When the captured image contains the perception and positioning module identification code 3, it is confirmed that the unmanned vehicle is observed. At this time, the three-dimensional position of the center position on the top plane of the unmanned vehicle currently detected is used to update the observation constraint, and the landing end position and tilt attitude are updated with the observed unmanned vehicle position and attitude, and then return to step S2, and re-plan the landing trajectory with the current position and attitude of the UAV as the landing starting point, update the landing trajectory and track until the position and attitude error between the unmanned vehicle and the UAV is less than the preset threshold. At this time, it is considered that the UAV has completed the landing process, and the UAV propeller is stopped and locked.

[0088] During the above-mentioned UAV take-off and landing process, the wireless transmission modules 5 of the UAV and the unmanned vehicle can continuously communicate to exchange information such as the position and posture of the UAV and the unmanned vehicle.

[0089] Figure 3 The detailed process of the inclined take-off and landing method of the tilt-quadrotor land-to-air drone provided by the present invention is demonstrated.

[0090] The present invention uses the above method to perform multiple trajectory replanning when an unmanned vehicle is observed during the landing process, which can improve the safety and stability of the landing.

[0091] Although the specific embodiments of the present invention have been described in a particular order, it should be understood that such actions or steps are required to be performed in the particular order shown or in a sequential order, or that all illustrated actions or steps are required to be performed to obtain the desired result. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details have been included in the above discussion, these should not be construed as limiting the scope of the present disclosure. Some features described in the context of a separate embodiment can also be implemented in a single implementation in combination. On the contrary, the various features described in the context of a single implementation can also be implemented in multiple implementations individually or in any suitable sub-combination.

[0092] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A landing method for a tilt-quadrotor land-to-air unmanned aerial vehicle (UAV) with an inclined take-off and landing system, the tilt-quadrotor land-to-air UAV with an inclined take-off and landing system comprising a tilt-quadrotor UAV and a ground unmanned vehicle, the tilt-quadrotor UAV being provided with an attitude sensor, a sensing and positioning module (2), and a wireless transmission module (5), a sensing and positioning module identification code (3) being provided at the center position of the top plane of the ground unmanned vehicle, the pitch angle of the top plane of the unmanned vehicle being 35°, and a wireless transmission module (5) being provided; the rotor mechanism of the tilt-quadrotor UAV being tilted around a set rotation axis to change the orientation of the rotor motor shaft and adjust different flight attitudes; It is characterized in that The method for landing a tilting quadrotor drone on the roof of an unmanned vehicle tilted to the ground includes the following steps: Step S21: The tilt-quadrotor UAV receives the position and attitude of the UAV sent by the UAV, and determines the landing end position and tilt attitude; Step S22: The tilt-rotor quadrotor UAV performs landing path planning based on the current position and attitude, landing endpoint position and tilt attitude, observation constraints, position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a landing trajectory; The observation constraint expression is: in, are the three-dimensional positions of the center position on the top plane of the unmanned vehicle in the ground coordinate system, They are respectively represented as the three-dimensional position of the UAV in the ground coordinate system, For adjustable small amount, is the pitch angle; The expression of the security constraint is: Among them, the superscript In the ground coordinate system, is the normal direction of the top plane of the unmanned vehicle, represents the transpose operation, Indicates the position of the UAV in the ground coordinate system, Indicates the center position of the unmanned vehicle on the top plane, is the matrix determined by the shape of the i-th ellipsoid obstacle, is the geometric center position of the i-th ellipsoid obstacle in the ground coordinate system, is the total number of obstacles; Step S23: After receiving the landing command, the tilt-quadrotor UAV tracks the landing trajectory; if the sensing and positioning module (2) onboard the tilt-quadrotor UAV observes an unmanned vehicle during the tracking process, the landing end position and tilt attitude are updated with the observed position and attitude of the unmanned vehicle, and the process returns to step S22; the landing is completed until the position and attitude of the tilt-quadrotor UAV are consistent with the end position and tilt attitude.

2. The landing method of the slope take-off and landing system of the tilt-quadrotor land-to-air UAV according to claim 1, characterized in that: Step S22 specifically includes: Step S22-1, setting the current position and attitude of the tilt-quadrotor UAV as the landing starting point, and setting the landing end position and tilt attitude as the landing end point; Step S22-2: Based on the landing start point and landing end point, an initial feasible landing path is generated using a path planning method; Step S22-3: Optimize the initial feasible landing path according to observation constraints, position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a landing trajectory.

3. The landing method of the tilt-quadrotor land-to-air UAV slope take-off and landing system according to claim 2, characterized in that: The tilt-rotating quad-rotor UAV is provided with a sensing and positioning module (2) for observing the unmanned vehicle below, and a sensing and positioning module identification code (3) is provided at the center position of the top plane of the unmanned vehicle.

4. The landing method of the tilt-quadrotor land-to-air UAV slope take-off and landing system according to claim 3, characterized in that: In step S22-3, the continuity constraint of the position and velocity refers to setting the optimization result of the initial feasible landing path to a polynomial trajectory of order 5 or above; The observation constraint is used to limit the center of the top plane of the unmanned vehicle to be within the visual range of the perception and positioning module (2); The dynamic constraints are used to limit the range of the fuselage pitch angle, the range of the fuselage pitch angle change rate, the range of the fuselage speed, and the range of the fuselage acceleration; The safety constraints are used to limit the distance between the drone position and the top plane of the unmanned vehicle and obstacles.

5. The landing method of the tilt-quadrotor land-to-air UAV slope take-off and landing system according to claim 4, characterized in that: The step S23 specifically includes: The sensing and positioning module (2) is used to sense in real time during the flight of the UAV. When the sensing and positioning module recognizes the sensing and positioning module identification code (3), it is confirmed that the UAV is observed, and the center position of the UAV on the top plane in the observation constraint is updated. The landing end position and the tilt attitude are updated with the observed UAV position and attitude, and the process returns to step S22 until the position and attitude error between the UAV and the tilt-rotating quad-rotor UAV is less than a preset threshold, and the landing is completed.

6. A take-off method for the inclined take-off and landing system of the tilt-quadrotor land-to-air UAV according to claim 1, characterized in that: The method for enabling a tilt-rotating quad-rotor drone to take off from the roof of an unmanned vehicle tilted to the ground includes the following steps: Step S11: The unmanned vehicle adjusts its roll angle so that the roll angle is less than a preset threshold, thereby forming a tilted roof. Step S12: The attitude sensor of the tilt-quadrotor UAV obtains the current pitch attitude, and adjusts the tilt mechanism of the tilt-quadrotor UAV based on the pitch attitude so that the rotor motor shaft is perpendicular to the horizontal plane; Step S13: The tilt-quadrotor UAV performs takeoff path planning based on position and velocity continuity constraints, dynamic constraints, and safety constraints to obtain a takeoff trajectory; Step S14: After receiving the take-off command, the tilt-quadrotor UAV tracks the take-off trajectory and completes the slope take-off.

7. The takeoff method of the tilt-quadrotor land-to-air UAV slope take-off and landing system according to claim 6, characterized in that: The tilt-quadrotor drone includes four tiltable rotor mechanisms and a tilt mechanism. The tilt mechanism can control the rotor structure to tilt around a set rotation axis and change the orientation of the rotor motor shaft in the rotor mechanism. The tilt-quadrotor drone is integrated with an attitude sensor for obtaining the pitch attitude of the tilt-quadrotor drone in real time.

8. The takeoff method of the tilt-quadrotor land-to-air UAV slope take-off and landing system according to claim 7, characterized in that: Step S13 specifically includes: Step S13-1, setting the current position and attitude of the tilt-quadrotor UAV as the take-off starting point, and setting the designated target position and attitude as the take-off end point; Step S13-2: Based on the takeoff starting point and takeoff end point, an initial feasible takeoff path is generated using a path planning method; Step S13-3: Optimize the initial feasible takeoff path according to the continuity constraints of position and velocity, dynamic constraints, and safety constraints to obtain a takeoff trajectory.

9. The takeoff method of the tilt-quadrotor land-to-air UAV slope take-off and landing system according to claim 8, characterized in that: In step S13-3, the continuity constraint of the position and velocity refers to setting the optimization result of the initial feasible takeoff path to a polynomial trajectory of order 5 or above; The dynamic constraints are used to limit the range of the fuselage pitch angle, the range of the fuselage pitch angle change rate, the range of the fuselage speed, and the range of the fuselage acceleration; The safety constraints are used to limit the distance between the fuselage position and the top plane of the unmanned vehicle and obstacles.

Images