Autonomous carrier landing control method for tilting quad-rotor unmanned aerial vehicle and related device

Abstract

The invention discloses an autonomous carrier landing control method and related device for a tilt quad-rotor unmanned aerial vehicle, and relates to the technical field of unmanned aerial vehicles, and the method comprises the steps: obtaining carrier landing task information and carrier landing surface environment information; determining a return track and a ship entering track; when the unmanned aerial vehicle flies to a ship entering position beside the ship, whether the ship entering condition is met or not is judged, if not, the unmanned aerial vehicle is set to be in an accompanying flying state beside the ship, relative hovering flying with the ship is achieved, the ship landing surface environment information is updated every preset time, and the step of judging whether the ship entering condition is met or not is returned; if yes, a trajectory tracking instruction is sent to the unmanned aerial vehicle, and the ship entering trajectory is tracked; when the unmanned aerial vehicle flies to a preset distance right above the landing point, whether the sea condition is stable or not is judged; if yes, carrying out carrier landing control by adopting a conventional helicopter mode control strategy; and if not, carrying out carrier landing control by adopting a five-channel control strategy. According to the invention, the landing safety and accuracy of the tilting quad-rotor unmanned aerial vehicle can be improved.

Description

Technical Field

[0001] The present application relates to the field of UAV technology, and in particular to an autonomous landing control method and related devices for a tilt-rotating quad-rotor UAV. Background Art

[0002] In order to achieve safe and autonomous landing of rotorcraft, scholars have conducted a lot of research. For safe landing, most landing plans are to estimate the deck movement and accurately capture the "quiet period". The quiet period refers to: the ship is affected by wind and waves on the sea, and there are six degrees of freedom movement: pitch, roll, bow pitch, sway, sway and vertical swing. The quiet period refers to the time period when the ship deck movement is relatively stable and suitable for aircraft landing. Usually, the deck pitch and roll are not higher than 2° and 4°~5° respectively. When the ship is in the "quiet period", that is, when the deck shakes relatively steadily, the aircraft descends rapidly to avoid accidents caused by the large difference between the aircraft attitude angle and the deck shaking angle when touching the ship, thereby completing a safe landing.

[0003] Although the deck motion prediction technology can accurately capture the static period of deck motion and reduce the risk of accidents during landing, it is difficult to capture the static period when performing rapid landing in high sea conditions, and it is necessary to hover on the ship for a long time to wait; if the landing is not performed during the static period and the conventional control strategy is adopted, the roll angle of the tilt-rotor aircraft and the roll angle of the ship may differ slightly during landing, which may easily cause accidents such as rotor touchdown; and when the left and right rotors shake on the deck, the ground effects of the rotors on both sides may be asymmetric, which will also increase the difficulty of controlling the rapid landing stage. Therefore, it is necessary to design a special landing control strategy for tilt-rotor aircraft for landing control in high sea conditions.

[0004] The control system of conventional aircraft adopts velocity-attitude cascade control due to under-actuation, which means that when tracking the position of the landing point on the deck, its attitude angle cannot track the shaking of the deck. Some scholars disconnect the outer loop position control when the aircraft approaches the deck, so that the attitude tracks the shaking of the deck for landing. In this way, the attitude of the aircraft can match the angle of the deck when the deck shakes violently, improving the safety of landing, but it will sacrifice the landing position accuracy to a certain extent.

[0005] Therefore, how to design an autonomous landing control scheme for a tilt-rotating quad-rotor UAV that can improve the safety and accuracy of landing has become a technical problem that urgently needs to be solved in this field. Summary of the invention

[0006] The purpose of this application is to provide a tilt-quadrotor UAV autonomous landing control method and related devices, which can improve the safety and accuracy of the tilt-quadrotor UAV landing.

[0007] To achieve the above objectives, this application provides the following solutions:

[0008] In a first aspect, the present application provides a tilt-quad-rotor UAV autonomous landing control method, the tilt-quad-rotor UAV autonomous landing control method comprising:

[0009] Acquire landing mission information and landing surface environment information; the landing mission information includes: landing point location, ship model, ship size and current location of the UAV; the landing surface environment information includes: surface flow field conditions and other aircraft retention conditions.

[0010] According to the landing mission information, a return trajectory and a ship approach trajectory are determined; the return trajectory is the return trajectory of the UAV flying to the side of the ship; the ship approach trajectory is the ship approach trajectory from flying next to the ship to a preset distance directly above the landing point.

[0011] When the UAV flies to the ship approach point next to the ship according to the return trajectory, it is determined whether the ship approach condition is currently met according to the landing surface environment information to obtain a first judgment result.

[0012] When the first judgment result is no, the UAV is set to fly alongside the ship to achieve relative hovering flight with the ship, update the landing surface environment information at preset intervals, and return to the step of "determining whether the conditions for entering the ship are currently met based on the landing surface environment information to obtain the first judgment result".

[0013] When the first judgment result is yes, a trajectory tracking instruction is sent to the UAV to track the trajectory of approaching the ship.

[0014] When the UAV flies to a preset distance directly above the landing point, it determines whether the sea condition is stable and obtains a second judgment result.

[0015] When the second judgment result is yes, a conventional helicopter mode control strategy is adopted to perform landing control; the conventional helicopter mode control strategy is a strategy established based on vertical control, longitudinal channel, lateral channel and heading channel.

[0016] When the second judgment result is no, a five-channel control strategy is adopted for landing control; the five-channel control strategy is a control strategy based on the conventional helicopter mode, which adds lateral periodic pitch linkage to the lateral channel and releases the cascade control structure of the lateral speed and roll angle.

[0017] Optionally, the adopting a conventional helicopter mode maneuvering strategy to perform landing control specifically includes:

[0018] The ship deck motion information is obtained; the ship deck motion information includes: deck heave motion, deck roll motion and deck pitch motion.

[0019] According to the ship deck motion information, the deck motion prediction technology is adopted to obtain the future deck motion information.

[0020] A rest period is determined according to the future deck motion information; the rest period is a time period when the ship deck motion is relatively stable and suitable for aircraft landing.

[0021] When the quiet period arrives, the horizontal displacement of the landing point is used as the tracking displacement of the UAV in the X and Y directions, and the deck's sinking and floating movement and the superimposed signal of the uniform descent at a preset speed are tracked in the height direction.

[0022] Optionally, the adopting a five-channel maneuvering strategy to perform landing control specifically includes:

[0023] The ship deck motion information is obtained; the ship deck motion information includes: deck heave motion, deck roll motion and deck pitch motion.

[0024] According to the ship deck motion information, the deck motion prediction technology is adopted to obtain the future deck motion information.

[0025] The deck roll motion is used as the target that the UAV roll angle needs to track; the roll angle is controlled by the differential of the left and right rotor collective pitches to track the deck roll angle.

[0026] The horizontal displacement of the landing point is used as the tracking displacement of the UAV in the X and Y directions; the Y direction displacement is controlled by the lateral periodic pitch linkage, and the height direction tracks the deck's sinking and floating motion and the superimposed signal of the uniform descent at a preset speed.

[0027] Optionally, the flight dynamics model under the conventional helicopter mode control strategy is:

[0028]

[0029] Among them, X is the state quantity, U is the control quantity, Y is the output quantity, u is the first speed of the body axis system, v is the second speed of the body axis system, w is the third speed of the body axis system, p is the first angular velocity of the body axis system, q is the second angular velocity of the body axis system, r is the third acceleration of the body axis system, φ is the first attitude angle, θ is the second attitude angle, ψ is the third attitude angle, is the derivative of the state quantity, f() is the UAV flight mechanics model, δ ver_c is the rotor collective pitch linkage, δ lat_cc is the total pitch difference of the left and right rotors, δ lon_cc is the front and rear rotor collective pitch differential, δ yaw_cyc It is the reverse differential of the longitudinal cyclic pitch change of the left and right rotors.

[0030] Optionally, the flight dynamics model under the five-channel control strategy is:

[0031]

[0032] Among them, X is the state quantity, U is the control quantity, Y is the output quantity, u is the first speed of the body axis system, v is the second speed of the body axis system, w is the third speed of the body axis system, p is the first angular velocity of the body axis system, q is the second angular velocity of the body axis system, r is the third acceleration of the body axis system, φ is the first attitude angle, θ is the second attitude angle, ψ is the third attitude angle, is the derivative of the state quantity, f() is the UAV flight mechanics model, δ ver_c is the rotor collective pitch linkage, δ lat_cc is the total pitch difference of the left and right rotors, δ lon_cc is the front and rear rotor collective pitch differential, δ yaw_cyc is the reverse differential of the longitudinal periodic pitch change of the left and right rotors, δ lat_cyc It is a lateral periodic pitch-changing linkage.

[0033] Optionally, the conditions for approaching the ship include: there are no obstacles on the approach path and at the landing point, the ship deck mooring device is ready, the current wind disturbance on the deck is lower than a preset wind disturbance value, and there is no danger in approaching the ship at this time.

[0034] In a second aspect, the present application provides a tilt-rotating quad-rotor UAV autonomous landing control device, the tilt-rotating quad-rotor UAV autonomous landing control device comprising:

[0035] The information acquisition module is used to obtain landing mission information and landing surface environment information; the landing mission information includes: landing point location, ship model, ship size and current location of the UAV; the landing surface environment information includes: surface flow field conditions and other aircraft retention conditions.

[0036] The trajectory determination module is used to determine the return trajectory and the ship approach trajectory according to the landing mission information; the return trajectory is the return trajectory of the UAV flying to the side of the ship; the ship approach trajectory is the ship approach trajectory from flying next to the ship to a preset distance directly above the landing point.

[0037] The first judgment module is used to determine whether the conditions for entering the ship are currently met based on the landing surface environment information when the UAV flies to the entry point next to the ship according to the return trajectory, and obtain a first judgment result.

[0038] The update and return module is used to set the UAV to fly alongside the ship to achieve relative hovering flight with the ship when the first judgment result is no, update the landing surface environment information at preset time intervals, and return to the step of "judging whether the conditions for entering the ship are currently met based on the landing surface environment information to obtain the first judgment result".

[0039] The tracking module is used to send a trajectory tracking instruction to the UAV to track the trajectory of approaching the ship when the first judgment result is yes.

[0040] The second judgment module is used to judge whether the sea condition is stable when the UAV flies to a preset distance directly above the landing point, and obtain a second judgment result.

[0041] The conventional helicopter mode manipulation strategy control module is used to adopt the conventional helicopter mode manipulation strategy for landing control when the second judgment result is yes; the conventional helicopter mode manipulation strategy is a strategy established based on vertical manipulation, longitudinal channel, lateral channel and heading channel.

[0042] A five-channel manipulation strategy control module is used to adopt a five-channel manipulation strategy for landing control when the second judgment result is no; the five-channel manipulation strategy is a manipulation strategy based on a conventional helicopter mode, adding a lateral periodic pitch linkage to the lateral channel to release the cascade control structure of the lateral speed and the roll angle.

[0043] In a third aspect, the present application provides a computer device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the above-described tilt-quadrotor UAV autonomous landing control methods.

[0044] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described methods for autonomous landing control of a tilt-quadrotor UAV.

[0045] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-mentioned tilt-quadrotor drone autonomous landing control methods.

[0046] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0047] The present application provides a tilt-quadrotor UAV autonomous landing control method and related devices, firstly, obtaining landing mission information and landing surface environment information; the landing mission information includes: landing point location, ship model, ship size and current location of the UAV; the landing surface environment information includes: ship surface flow field conditions and other aircraft retention conditions; according to the landing mission information, a return trajectory and a ship approach trajectory are determined; the return trajectory is the return trajectory of the UAV flying to the side of the ship; the ship approach trajectory is the ship approach trajectory from the side of the ship to a preset distance directly above the landing point; secondly, when the UAV flies to the ship approach point next to the ship according to the return trajectory, it is determined whether the ship approach conditions are currently met according to the landing surface environment information, and a first judgment result is obtained; when the first judgment result is no, the UAV is set to be in a companion flight state beside the ship to achieve relative hovering flight with the ship, and every preset The landing surface environment information is updated at the same time, and the step of "according to the landing surface environment information, judging whether the conditions for entering the ship are currently met to obtain the first judgment result" is returned; when the first judgment result is yes, a trajectory tracking instruction is sent to the UAV to track the entry trajectory; then, when the UAV flies to a preset distance directly above the landing point, it is judged whether the sea conditions are stable to obtain a second judgment result; when the second judgment result is yes, a conventional helicopter mode control strategy is adopted for landing control; the conventional helicopter mode control strategy is a strategy established based on vertical control, longitudinal channel, lateral channel and heading channel; when the second judgment result is no, a five-channel control strategy is adopted for landing control; the five-channel control strategy is a control strategy based on the conventional helicopter mode, adding lateral periodic pitch linkage to the lateral channel, and releasing the cascade control structure of the lateral speed and roll angle. This application provides two landing control strategies for tilt-rotating quad-rotor UAVs under two conditions: stable sea conditions and high sea conditions. For different landing environments and sea conditions, the UAV can autonomously select different control strategies to complete rapid landing. At the same time, based on the control redundancy of the tilt-quadrotor UAV, this application designs a five-channel control strategy for its helicopter mode. This control strategy can achieve the same-level control of the UAV's lateral speed and roll angle, so that the UAV can simultaneously track the lateral position and roll angle of the deck, thereby improving the accuracy and safety of landing. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1This is an application environment diagram of an autonomous landing control method for a tilt-quadrotor UAV in one embodiment of the present application.

[0050] Figure 2 A flowchart of an autonomous landing control method for a tilt-quadrotor UAV provided in one embodiment of the present application.

[0051] Figure 3 A schematic diagram of the control structure under a conventional helicopter mode control strategy provided in one embodiment of the present application.

[0052] Figure 4 A schematic diagram of the control structure under the five-channel control strategy of helicopter mode provided in one embodiment of the present application.

[0053] Figure 5 A schematic diagram of the autonomous landing process of a tilt-quadrotor UAV provided in one embodiment of the present application.

[0054] Figure 6 A schematic diagram of the functional modules of an autonomous landing control device for a tilt-quadrotor UAV provided in one embodiment of the present application.

[0055] Figure 7 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0058] When landing, tilt-rotor drones usually use helicopter mode for vertical landing, and the conventional helicopter mode has a four-channel control strategy, which can meet the landing requirements when the sea conditions are relatively stable. However, when the sea conditions are high and the deck movement is more intense, the rotors and wings of the tilt-rotor quadcopter are prone to accidents such as touching the ground. The present application discloses a method for automatically switching control strategies of a tilt-rotor UAV when landing: when the sea condition is stable, the flight control system of the tilt-rotor quad-rotor UAV maintains a conventional four-channel helicopter mode control strategy, that is, adopts four control variables, namely, collective pitch linkage, front and rear rotor collective pitch differential, left and right rotor collective pitch differential, and left and right rotor longitudinal cyclic pitch differential; according to the deck motion information, the position of the UAV in three directions tracks and compensates for the horizontal displacement and height swell of the deck, and when the "quiescent period" is captured, it descends in time to achieve rapid landing; in high sea conditions, the deck moves violently and it is difficult to wait for the "quiescent period". After the tilt-rotor quad-rotor UAV completes its mission, it flies back to just above the landing point, and its flight control system automatically switches to a five-channel control strategy and control structure, that is, the lateral cyclic pitch linkage control variable is added in the lateral direction to achieve decoupling of the lateral speed and the roll angle, and while the position channel tracks the horizontal displacement and height swell, the roll angle tracks the roll angle of the deck to match the roll motion of the ship, and then completes the rapid landing. Therefore, in order to achieve tracking and compensation of the roll motion of the deck while maintaining position control during landing, it is necessary to make use of the tilt-quadrotor UAV's own control redundancy and improve its control strategy, which is very meaningful for further improving the safety and accuracy of landing.

[0059] The autonomous landing control method of the tilt-rotating quad-rotor UAV provided in the embodiment of the present application can be applied to Figure 1In the application environment shown, the terminal 102 communicates with the server 104 through a network. The data storage system can store data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 may send the acquired landing mission information and landing surface environment information to the server 104, wherein the landing mission information includes: the landing point location, the ship model, the ship size and the current location of the UAV; the landing surface environment information includes: the ship surface flow field conditions and the retention conditions of other aircraft; after receiving the landing mission information and the landing surface environment information, the server 104 determines the return trajectory and the ship approach trajectory according to the landing mission information and the landing surface environment information; the return trajectory is the return trajectory of the UAV flying to the side of the ship; the ship approach trajectory is the ship approach trajectory from the side of the ship to a preset distance directly above the landing point; when the UAV flies to the ship approach point next to the ship according to the return trajectory, it is determined whether the ship approach condition is currently met according to the landing surface environment information to obtain a first judgment result; when the first judgment result is no, the UAV is set to be in a companion flight state beside the ship, Realize relative hovering flight with the ship, update the landing surface environment information at preset intervals, and return to the step of "determine whether the conditions for entering the ship are met according to the landing surface environment information, and obtain the first judgment result"; when the first judgment result is yes, send a trajectory tracking instruction to the drone to track the entry trajectory; when the drone flies to a preset distance directly above the landing point, determine whether the sea conditions are stable and obtain a second judgment result; when the second judgment result is yes, adopt the conventional helicopter mode control strategy for landing control; the conventional helicopter mode control strategy is a strategy based on vertical control, longitudinal channel, lateral channel and heading channel; when the second judgment result is no, adopt the five-channel control strategy for landing control; the five-channel control strategy is a control strategy based on the conventional helicopter mode, adding lateral periodic pitch linkage to the lateral channel, and releasing the cascade control structure of lateral speed and roll angle. The server 104 can feedback the obtained control strategy to the terminal 102. In addition, in some embodiments, the autonomous landing control method of the tilt-quadrotor UAV can also be implemented independently by the server 104 or the terminal 102. For example, the terminal 102 can directly perform autonomous landing control of the UAV based on the landing mission information and the landing surface environment information, or the server 104 can obtain the landing mission information and the landing surface environment information from the data storage system, and perform autonomous landing control of the UAV based on the landing mission information and the landing surface environment information.

[0060] The terminal 102 may be, but is not limited to, various desktop computers, laptop computers, smart phones and tablet computers, IoT devices and portable wearable devices. The server 104 may be implemented as an independent server or a server cluster consisting of multiple servers, or may be a cloud server.

[0061] In an exemplary embodiment, Figure 2 As shown, a tilt-rotating quad-rotor UAV autonomous landing control method is provided. The method is executed by a computer device, and can be executed by a computer device such as a terminal or a server alone, or can be executed by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The server 104 in the example is used as an example to illustrate the method, which includes the following steps S1 to S8. Among them:

[0062] S1: Acquire landing mission information and landing surface environment information; the landing mission information includes: landing point location, ship model, ship size and current location of the UAV; the landing surface environment information includes: surface flow field conditions and other aircraft retention conditions.

[0063] S2: Determine a return trajectory and a ship approach trajectory according to the landing mission information; the return trajectory is the return trajectory of the UAV flying to the side of the ship; the ship approach trajectory is the ship approach trajectory from flying beside the ship to a preset distance directly above the landing point.

[0064] S3: When the UAV flies to the ship approach point next to the ship according to the return trajectory, it is determined whether the ship approach conditions are currently met according to the landing surface environment information to obtain a first judgment result; the ship approach conditions include: there are no obstacles on the ship approach path and at the landing point, the ship mooring device is ready, the current wind disturbance on the deck is lower than the preset wind disturbance value, and there is no danger in entering the ship at this time.

[0065] S4: When the first judgment result is no, the UAV is set to be in a state of accompanying the ship to achieve relative hovering flight with the ship, update the landing surface environment information at preset intervals, and return to the step of "determining whether the conditions for entering the ship are currently met based on the landing surface environment information to obtain the first judgment result".

[0066] S5: When the first judgment result is yes, a trajectory tracking instruction is sent to the UAV to track the trajectory of approaching the ship.

[0067] S6: When the UAV flies to a preset distance directly above the landing point, it is determined whether the sea condition is stable to obtain a second determination result.

[0068] S7: When the second judgment result is yes, a conventional helicopter mode control strategy is adopted to perform landing control; the conventional helicopter mode control strategy is a strategy established based on vertical control, longitudinal channel, lateral channel and heading channel.

[0069] S8: When the second judgment result is no, a five-channel control strategy is adopted for landing control; the five-channel control strategy is a control strategy based on the conventional helicopter mode, which adds lateral periodic pitch linkage to the lateral channel and releases the cascade control structure of the lateral speed and the roll angle.

[0070] By implementing the above steps S1 to S8, two landing control strategies for the tilt-quadrotor UAV are respectively given under the two conditions of stable sea conditions and high sea conditions. For different landing environments and sea conditions, the UAV can autonomously select different control strategies to complete rapid landing. At the same time, according to the control redundancy of the tilt-quadrotor UAV, this application designs a five-channel control strategy for its helicopter mode. This control strategy can achieve the same-level control of the UAV's lateral speed and roll angle, so that the UAV can simultaneously track the lateral position and roll angle of the deck, thereby improving the accuracy and safety of landing.

[0071] In another exemplary embodiment of the present application, in step S7, the conventional helicopter mode maneuvering strategy is used to perform landing control, specifically including:

[0072] S71: Acquire the ship deck motion information; the ship deck motion information includes: deck heave motion, deck roll motion and deck pitch motion.

[0073] S72: Based on the ship deck motion information, a deck motion prediction technology is used to obtain future deck motion information.

[0074] S73: Determine a rest period according to the future deck motion information; the rest period is a time period when the ship deck motion is relatively stable and suitable for aircraft landing.

[0075] S74: When the quiet period arrives, the horizontal displacement of the landing point is used as the tracking displacement of the UAV in the X and Y directions, and the deck's floating movement and the superimposed signal of the uniform descent at a preset speed are tracked in the height direction.

[0076] The flight dynamics model under the conventional helicopter mode control strategy is:

[0077]

[0078] Among them, X is the state quantity, U is the control quantity, Y is the output quantity, u is the first speed of the body axis system, v is the second speed of the body axis system, w is the third speed of the body axis system, p is the first angular velocity of the body axis system, q is the second angular velocity of the body axis system, r is the third acceleration of the body axis system, φ is the first attitude angle, θ is the second attitude angle, ψ is the third attitude angle, is the derivative of the state quantity, f() is the UAV flight mechanics model, δ ver_c is the rotor collective pitch linkage, δ lat_cc is the total pitch difference of the left and right rotors, δ lon_cc is the front and rear rotor collective pitch differential, δ yaw_cyc It is the reverse differential of the longitudinal cyclic pitch change of the left and right rotors.

[0079] In another exemplary embodiment of the present application, in step S8, the five-channel maneuvering strategy is used to perform landing control, specifically including:

[0080] S81: Acquire the ship deck motion information; the ship deck motion information includes: deck heave motion, deck roll motion and deck pitch motion.

[0081] S82: Based on the ship deck motion information, a deck motion prediction technology is used to obtain future deck motion information.

[0082] S83: The deck roll motion is used as the target to be tracked by the roll angle of the UAV; the roll angle is controlled by the collective pitch differential of the left and right rotors to track the deck roll angle.

[0083] S84: The horizontal displacement of the landing point is used as the tracking displacement of the UAV in the X and Y directions; the Y direction displacement is controlled by the lateral periodic pitch linkage, and the height direction tracks the deck's buoyancy and uniform descent at a preset speed.

[0084] The flight dynamics model under the five-channel control strategy is:

[0085]

[0086]

[0087] Among them, X is the state quantity, U is the control quantity, Y is the output quantity, u is the first speed of the body axis system, v is the second speed of the body axis system, w is the third speed of the body axis system, p is the first angular velocity of the body axis system, q is the second angular velocity of the body axis system, r is the third acceleration of the body axis system, φ is the first attitude angle, θ is the second attitude angle, ψ is the third attitude angle, is the derivative of the state quantity, f() is the UAV flight mechanics model, δ ver_c is the rotor collective pitch linkage, δ lat_ccis the total pitch difference of the left and right rotors, δ lon_cc is the front and rear rotor collective pitch differential, δ yaw_cyc is the reverse differential of the longitudinal periodic pitch change of the left and right rotors, δ lat_cyc It is a lateral periodic pitch-changing linkage.

[0088] As an optional implementation method, step 1: the deck personnel enter the landing mission information (landing point location, ship model and size, and current position of the drone, etc.) into the drone flight control system, and the flight control system autonomously plans the return trajectory. The specific method is: according to the specific model and size of the ship, choose to enter the ship from the rear or side of the ship. According to the current position of the drone, the position of the ship, and the position of the entry point, the return trajectory of the drone flying to the side of the ship and the entry trajectory from the side of the ship to 5m directly above the landing point are automatically planned.

[0089] Step 2: After completing step 1, the tilt-rotor UAV will fly to the ship's entry point according to the planned return trajectory. The flight control system determines whether the current conditions for entering the ship are met based on the ship's surface environment (ship surface flow field conditions, whether there are other aircraft stranded, etc.); when the ship's surface environment conditions do not meet the requirements for entering the ship, the flight control system sets the UAV to accompany the ship by default, achieving relative hovering flight with the ship, and updates the ship's surface environment information every 20 seconds; when the ship's surface environment meets the conditions for entering the ship, the flight control system sends a trajectory tracking command to the UAV to track the automatically generated ship entry trajectory.

[0090] Step 3: After completing step 2, the tilt-quadrotor UAV flies to 5m above the landing point, achieves relative hovering flight with the ship, and begins to track the rising and falling movement of the deck in the height direction to ensure that the relative distance between the aircraft and the deck remains unchanged. At this time, the landing mission enters the final stage: the rapid landing stage. In this stage, the sea conditions and ship environment are first judged: based on the deck motion information and the estimated future deck motion, if it is in low or medium sea conditions and the ship has an obvious rest period, a landing controller with a conventional helicopter mode control strategy is used to perform a rapid landing during the rest period; if it is in a higher sea condition, the ship shakes violently and there is no obvious rest period, a controller with a five-channel landing control strategy specially designed for tilt-quadrotor UAVs is used for a rapid landing. The specific situations are as follows:

[0091] If the sea conditions are stable during landing, the tilt-rotor UAV will be controlled according to the conventional helicopter mode control strategy, that is, the rotor collective pitch is linked in the same direction δ ver_c As a vertical control, the longitudinal channel selects the front and rear rotor collective pitch differential δ lon_cc , the lateral channel selects the total pitch differential of the left and right rotors δ lat_cc , the heading channel selects the left and right rotor longitudinal periodic pitch reverse differential δ yaw_cycThe specific process is as follows: collect and process the ship deck motion information, and estimate the deck motion in 3 to 5 seconds, including deck lifting, rolling, and pitching; according to the deck motion prediction technology (the deck motion is driven by waves. Although it can be regarded as a pure random process at a certain moment, it can be regarded as a stable random process from a long-term statistical point of view, that is, it can be predicted. Currently commonly used methods: time series, Kalman filter prediction method, particle filter prediction method, etc. Estimate the deck motion information in the next few seconds and judge the quiet period.) The future motion information is obtained to capture the "quiet period", that is, the pitch and roll angles are not higher than 2° and 4°~5° respectively; when the quiet period arrives, the displacement of the drone in the X and Y directions continues to track the horizontal displacement of the landing point, and tracks the deck's sinking and floating motion and the superimposed signal of a uniform descent at a speed of 1m / s in the height direction to ensure that the relative speed between the drone and the deck remains constant and achieves safe touchdown; the specific structure is as follows Figure 3 shown.

[0092] If the sea conditions are high during landing, it is difficult to capture a suitable rest period. A five-channel control strategy designed for landing of tilt-rotating quad-rotor UAV is adopted. That is, on the basis of the control strategy of conventional helicopter mode, a lateral periodic variable pitch linkage δ is added to the lateral channel. lat_cyc , release the cascade control structure of lateral speed and roll angle; the specific process is as follows: collect and process the ship deck motion information, and estimate the deck motion in 3 to 5 seconds, including deck lifting, rolling and pitching; according to the future deck motion information obtained by the deck motion prediction technology, the deck roll motion is used as the target to be tracked by the UAV roll angle, and the roll angle is controlled by the total pitch differential of the left and right rotors to track the deck roll angle; at the same time, the horizontal displacement of the landing point is used as the tracking instruction of the UAV's position in the X and Y directions, among which the Y direction displacement is controlled by the lateral periodic pitch linkage; in the height direction, track the deck's sinking and floating motion and the superimposed signal of the uniform descent at a speed of 1m / s to ensure that the relative speed between the UAV and the deck remains constant; realize the real-time matching of the UAV roll angle with the deck roll angle during the landing and descent process to complete the safe touchdown; the specific control structure is as follows Figure 4 shown.

[0093] The above landing steps are shown in the figure below: Figure 5 shown.

[0094] In summary, the landing control strategy under high sea conditions proposed in this application is simple and effective. Since the control redundancy of the tilt-quad-rotor UAV in helicopter mode is fully utilized, the same-level control of lateral speed and roll angle is achieved, and the accuracy and safety of landing under high sea conditions are improved. At the same time, the autonomous landing control method of the tilt-quad-rotor UAV proposed in this application can be switched according to the specific landing sea conditions, so that the UAV can choose a more appropriate landing strategy in both stable sea conditions and high sea conditions.

[0095] The present application also provides an application scenario, which applies the above-mentioned tilt-quadrotor UAV autonomous landing control method. Specifically: The tilt-quadrotor UAV autonomous landing control method provided in this embodiment can be applied in the UAV autonomous landing scenario. The UAV autonomous landing scenario includes: return trajectory planning and tracking links, ship-side escort and ship entry links, and rapid landing links; in the return trajectory planning and tracking link, the return path is generated and the ship is flown back according to the position of the aircraft and the ship; in the ship-side escort and ship entry links, the timing of entering the ship is determined according to the ship surface environment; finally, in the rapid landing link, the control strategy of the control system during landing is selected according to the sea conditions.

[0096] Based on the same inventive concept, the embodiment of the present application also provides a tilt-quad-rotor drone autonomous landing control device for implementing the above-mentioned tilt-quad-rotor drone autonomous landing control method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in one or more tilt-quad-rotor drone autonomous landing control device embodiments provided below can refer to the limitations of the tilt-quad-rotor drone autonomous landing control method above, and will not be repeated here.

[0097] In an exemplary embodiment, Figure 6 As shown, a tilt-rotating quad-rotor UAV autonomous landing control device is provided, and the tilt-rotating quad-rotor UAV autonomous landing control device comprises:

[0098] The information acquisition module M1 is used to acquire the landing mission information and the landing surface environment information; the landing mission information includes: the landing point location, the ship model, the ship size and the current location of the UAV; the landing surface environment information includes: the ship surface flow field and other aircraft retention conditions;

[0099] The trajectory determination module M2 is used to determine a return trajectory and a ship approach trajectory according to the landing mission information; the return trajectory is the return trajectory of the UAV flying to the side of the ship; the ship approach trajectory is the ship approach trajectory from the side of the ship to a preset distance directly above the landing point;

[0100] The first judgment module M3 is used to determine whether the ship entry condition is currently met according to the landing surface environment information when the UAV flies to the ship entry point next to the ship according to the return trajectory, and obtain a first judgment result;

[0101] The updating and returning module M4 is used for setting the UAV to be in a state of accompanying the ship to achieve relative hovering flight with the ship when the first judgment result is no, updating the landing surface environment information at a preset time interval, and returning to the step of "judging whether the conditions for entering the ship are currently met according to the landing surface environment information to obtain the first judgment result";

[0102] A tracking module M5 is used to send a trajectory tracking instruction to the UAV to track the trajectory of approaching the ship when the first judgment result is yes;

[0103] The second judgment module M6 is used to judge whether the sea condition is stable when the UAV flies to a preset distance directly above the landing point, and obtain a second judgment result;

[0104] A conventional helicopter mode manipulation strategy control module M7, configured to, when the second judgment result is yes, adopt a conventional helicopter mode manipulation strategy for landing control; the conventional helicopter mode manipulation strategy is a strategy established based on vertical manipulation, longitudinal channel, lateral channel and heading channel;

[0105] The five-channel manipulation strategy control module M8 is used to adopt a five-channel manipulation strategy for landing control when the second judgment result is no; the five-channel manipulation strategy is a manipulation strategy based on the conventional helicopter mode, which adds lateral periodic pitch linkage to the lateral channel and releases the cascade control structure of the lateral speed and the roll angle.

[0106] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 7 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store landing mission information and landing surface environment information. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for autonomous landing control of a tilt-rotating quad-rotor unmanned aerial vehicle is implemented.

[0107] Those skilled in the art will understand that Figure 7The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0108] In an exemplary embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the above-mentioned method embodiments are implemented when the processor executes the computer program.

[0109] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the above-mentioned method embodiments are implemented.

[0110] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the above-mentioned method embodiments are implemented.

[0111] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0112] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0113] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0114] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for autonomous landing control of a tilt-quadrotor UAV, characterized in that: The autonomous landing control method of the tilt-quadrotor UAV comprises: Acquire landing mission information and landing surface environment information; the landing mission information includes: landing point location, ship model, ship size and current location of the UAV; the landing surface environment information includes: surface flow field conditions and other aircraft retention conditions; According to the landing mission information, a return trajectory and a ship approach trajectory are determined; the return trajectory is the return trajectory of the UAV flying to the side of the ship; the ship approach trajectory is the ship approach trajectory from the side of the ship to a preset distance directly above the landing point; When the UAV flies to the ship approach point next to the ship according to the return trajectory, it is determined whether the ship approach condition is currently met according to the landing surface environment information to obtain a first determination result; When the first judgment result is no, the UAV is set to be in a state of accompanying the ship to achieve relative hovering flight with the ship, the landing surface environment information is updated at a preset time, and the process returns to the step of "determining whether the conditions for entering the ship are met according to the landing surface environment information, and obtaining the first judgment result"; When the first judgment result is yes, sending a trajectory tracking instruction to the UAV to track the approaching trajectory; When the UAV flies to a preset distance directly above the landing point, it is determined whether the sea condition is stable, and a second determination result is obtained; When the second judgment result is yes, a conventional helicopter mode control strategy is adopted to perform landing control; the conventional helicopter mode control strategy is a strategy established based on vertical control, longitudinal channel, lateral channel and heading channel; When the second judgment result is no, a five-channel control strategy is adopted for landing control; the five-channel control strategy is a control strategy based on the conventional helicopter mode, which adds lateral periodic pitch linkage to the lateral channel and releases the cascade control structure of the lateral speed and roll angle.

2. The autonomous landing control method for a tilt-quadrotor UAV according to claim 1, characterized in that: The conventional helicopter mode control strategy is used to perform landing control, specifically including: Acquire ship deck motion information; the ship deck motion information includes: deck heave motion, deck roll motion and deck pitch motion; According to the ship deck motion information, the future deck motion information is obtained by using a deck motion prediction technology; Determining a rest period according to the future deck motion information; the rest period is a time period when the ship deck motion is relatively stable and suitable for aircraft landing; When the quiet period arrives, the horizontal displacement of the landing point is used as the tracking displacement of the UAV in the X and Y directions, and the deck's sinking and floating movement and the superimposed signal of the uniform descent at a preset speed are tracked in the height direction.

3. The autonomous landing control method for a tilt-quadrotor UAV according to claim 1, characterized in that: The five-channel control strategy is used to perform landing control, specifically including: Acquire ship deck motion information; the ship deck motion information includes: deck heave motion, deck roll motion and deck pitch motion; According to the ship deck motion information, the future deck motion information is obtained by using a deck motion prediction technology; The deck roll motion is used as the target to be tracked by the roll angle of the UAV; the roll angle is controlled by the differential of the left and right rotor collective pitches to track the deck roll angle; The horizontal displacement of the landing point is used as the tracking displacement of the UAV in the X and Y directions; the Y direction displacement is controlled by the lateral periodic pitch linkage, and the height direction tracks the deck's sinking and floating motion and the superimposed signal of the uniform descent at a preset speed.

4. The autonomous landing control method for a tilt-quadrotor UAV according to claim 1, characterized in that: The flight dynamics model under the conventional helicopter mode control strategy is: Among them, X is the state quantity, U is the control quantity, Y is the output quantity, u is the first speed of the body axis system, v is the second speed of the body axis system, w is the third speed of the body axis system, p is the first angular velocity of the body axis system, q is the second angular velocity of the body axis system, r is the third acceleration of the body axis system, φ is the first attitude angle, θ is the second attitude angle, ψ is the third attitude angle, is the derivative of the state quantity, f() is the UAV flight mechanics model, δ ver_c is the rotor collective pitch linkage, δ lat_cc is the total pitch difference of the left and right rotors, δ lon_cc is the front and rear rotor collective pitch differential, δ yaw_cyc It is the reverse differential of the longitudinal cyclic pitch change of the left and right rotors.

5. The autonomous landing control method for a tilt-quadrotor UAV according to claim 1, characterized in that: The flight dynamics model under the five-channel control strategy is: Among them, X is the state quantity, U is the control quantity, Y is the output quantity, u is the first speed of the body axis system, v is the second speed of the body axis system, w is the third speed of the body axis system, p is the first angular velocity of the body axis system, q is the second angular velocity of the body axis system, r is the third acceleration of the body axis system, φ is the first attitude angle, θ is the second attitude angle, ψ is the third attitude angle, is the derivative of the state quantity, f() is the UAV flight mechanics model, δ ver_c is the rotor collective pitch linkage, δ lat_cc is the total pitch difference of the left and right rotors, δ lon_cc is the front and rear rotor collective pitch differential, δ yaw_cyc is the reverse differential of the longitudinal periodic pitch change of the left and right rotors, δ lat_cyc It is a lateral periodic pitch-changing linkage.

6. The autonomous landing control method for a tilt-quadrotor UAV according to claim 1, characterized in that: The conditions for approaching the ship include: there are no obstacles on the approach path and at the landing point, the ship's deck mooring devices are ready, the current wind disturbance on the deck is lower than the preset wind disturbance value, and there is no danger in approaching the ship at this time.

7. A tilt-quadrotor UAV autonomous landing control device, characterized in that: The tilt-quadrotor UAV autonomous landing control device comprises: An information acquisition module is used to acquire landing mission information and landing surface environment information; the landing mission information includes: landing point location, ship model, ship size and current location of the UAV; the landing surface environment information includes: surface flow field conditions and other aircraft retention conditions; A trajectory determination module is used to determine a return trajectory and a ship approach trajectory according to the landing mission information; the return trajectory is a return trajectory of the UAV flying to the side of the ship; the ship approach trajectory is a ship approach trajectory from the side of the ship to a preset distance directly above the landing point; A first judgment module is used to determine whether the ship entry condition is currently met according to the landing surface environment information when the UAV flies to the ship entry position next to the ship according to the return trajectory, and obtain a first judgment result; An updating and returning module, for setting the UAV to be in a state of accompanying the ship to achieve relative hovering flight with the ship when the first judgment result is no, updating the landing surface environment information at preset intervals, and returning to the step of "judging whether the conditions for entering the ship are currently met according to the landing surface environment information to obtain the first judgment result"; A tracking module, configured to send a trajectory tracking instruction to the UAV to track the trajectory of approaching the ship when the first judgment result is yes; The second judgment module is used to judge whether the sea condition is stable when the UAV flies to a preset distance directly above the landing point, and obtain a second judgment result; A conventional helicopter mode manipulation strategy control module, configured to, when the second judgment result is yes, adopt a conventional helicopter mode manipulation strategy to perform landing control; the conventional helicopter mode manipulation strategy is a strategy established based on vertical manipulation, longitudinal channel, lateral channel and heading channel; A five-channel manipulation strategy control module is used to adopt a five-channel manipulation strategy for landing control when the second judgment result is no; the five-channel manipulation strategy is a manipulation strategy based on a conventional helicopter mode, adding a lateral periodic pitch linkage to the lateral channel to release the cascade control structure of the lateral speed and the roll angle.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the autonomous landing control method for a tilt-quadrotor UAV as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the autonomous landing control method of the tilt-quadrotor UAV described in any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the autonomous landing control method of the tilt-quadrotor UAV described in any one of claims 1 to 6 is implemented.

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