A method and system for controlling take-off and landing of a drone

Abstract

The application discloses a kind of unmanned plane take-off and landing control method and system, belong to unmanned plane autonomous take-off and landing control technical field, this system includes vibration suppression mode library construction module, vibration suppression mode library activation module, comparison analysis module, comparison judging module and unmanned plane landing execution module, by constructing vibration suppression mode library and the condition trigger of configuration vibration suppression mode library, based on vibration suppression mode under vibration suppression mode library, real-time receiving and analyzing vertical acceleration data output by inertial measurement unit, and with vibration suppression mode library in invalid vibration characteristic mode in real time comparison, when meeting preset matching degree threshold, it is determined as the vertical vibration of mobile platform, unmanned plane is instructed as not to execute the vertical vibration of this mobile platform corresponding instruction, the method is by identifying and inhibiting invalid vibration, while maintaining stable landing form when visual information is unreliable, effectively improve the take-off and landing stability of unmanned plane in complex environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicle autonomous take-off and landing control, and particularly relates to an unmanned aerial vehicle take-off and landing control method and system. BACKGROUND

[0002] As a flexible and efficient aerial operation platform, the unmanned aerial vehicle shows a broad application prospect in industrial environments such as automatic logistics and intelligent warehousing, especially when performing precise cargo transfer and inspection tasks.

[0003] In actual application, the mobile platform used for providing landing support in contrast to the unmanned aerial vehicle may encounter uneven ground, joints or obstacles during movement, resulting in instantaneous and high-frequency mechanical vibration of the mobile platform itself. For example, when the ground transfer vehicle rolls over the floor joint or metal cover plate in the warehouse center, the vehicle body and the landing platform on the top thereof will produce vertical vibration with a short duration but a large amplitude and instantaneous attitude tilt. The inertial measurement unit (IMU) on the unmanned aerial vehicle will accurately perceive and record these vertical vibrations as sharp changes in acceleration. If the unmanned aerial vehicle control system completely responds according to the data of the inertial measurement unit, attempts to offset these vibrations by quickly adjusting the rotor speed, and causes the unmanned aerial vehicle to perform a series of unnecessary and violent up-and-down shaking.

[0004] In addition, the visual markers on which the unmanned aerial vehicle relies for positioning will vibrate when the mobile platform rolls over the floor joint or metal cover plate, resulting in difficulty in identification, intermittent loss of information or position jumping, and a significant decrease in confidence, which cannot provide stable and reliable positioning and attitude reference for the unmanned aerial vehicle.

[0005] Therefore, there is an urgent need for an improved solution to the above problems. SUMMARY

[0006] The purpose of the present application is to provide an unmanned aerial vehicle take-off and landing control method and system, which can identify and suppress high-frequency invalid vibration of the mobile platform and maintain stable landing posture of the unmanned aerial vehicle when visual positioning information is unreliable, thereby improving the take-off and landing stability of the unmanned aerial vehicle on the complex mobile platform.

[0007] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0008] As an aspect of the present application, an unmanned aerial vehicle take-off and landing control method is provided, comprising:

[0009] S1, providing an unmanned aerial vehicle and a mobile platform configured with an inertial measurement unit and a vision system;

[0010] S2, constructing a vibration suppression mode library including a plurality of invalid vibration characteristic patterns indicating that inertial measurement unit detects acceleration change characteristics inconsistent with the low-speed motion trend of the mobile platform as a whole in the obtained inertial measurement unit data, and configuring a condition trigger for applying the vibration suppression mode library;

[0011] S3, when it is judged that the distance between the UAV and the mobile platform is lower than a preset distance threshold, and the visual positioning information about the mobile platform obtained by the visual system is lower than a preset reliability threshold, a vibration suppression mode is enabled, which indicates that the UAV and the mobile platform trigger the condition trigger to apply the vibration suppression mode library under the current running state;

[0012] S4, in the vibration suppression mode, real-time receiving and analyzing the vertical acceleration data output by the inertial measurement unit, and real-time comparing the current vertical acceleration data output by the inertial measurement unit with the invalid vibration characteristic patterns in the vibration suppression mode library;

[0013] S5, when it is judged that the current vertical acceleration data output by the inertial measurement unit and the invalid vibration characteristic pattern satisfy a preset matching degree threshold, it is judged that the current vertical acceleration data output by the inertial measurement unit indicates the vertical vibration of the mobile platform;

[0014] S6, when it is judged that the vertical vibration of the mobile platform, the UAV is instructed not to execute the vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform, and the UAV maintains a preset landing form.

[0015] Compared with the prior art, the UAV take-off and landing control method of the application, by constructing a vibration suppression mode library and configuring a condition trigger for applying the vibration suppression mode library, when it is judged that the distance between the UAV and the mobile platform is lower than a preset distance threshold, and the visual positioning information about the mobile platform obtained by the visual system is lower than a preset reliability threshold, a vibration suppression mode is enabled, in which mode real-time receiving and analyzing the vertical acceleration data output by the inertial measurement unit, and real-time comparing the current vertical acceleration data output by the inertial measurement unit with the invalid vibration characteristic patterns in the vibration suppression mode library, when it is judged that the current vertical acceleration data output by the inertial measurement unit and the invalid vibration characteristic pattern satisfy a preset matching degree threshold, it is judged that the current vertical acceleration data output by the inertial measurement unit indicates the vertical vibration of the mobile platform, the UAV is instructed not to execute the vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform, and the UAV maintains a preset landing form, the method identifies and suppresses invalid vibration, while maintaining a stable landing form when visual information is unreliable, effectively improving the take-off and landing stability of the UAV in complex environments.

[0016] Further, the step of constructing the vibration suppression mode library and configuring a conditional trigger applying the vibration suppression mode library, wherein the vibration suppression mode library comprises a plurality of invalid vibration feature modes, the invalid vibration feature mode indicates that the inertial measurement unit detects an acceleration change feature in the inertial measurement unit data that is inconsistent with the overall low-speed motion trend of the mobile platform, comprises:

[0017] S21, before receiving the landing request information sent by the UAV to the mobile platform and when the mobile platform passes through the joint, comparing the vertical acceleration data output by the inertial measurement unit with the vertical motion image data output by the visual system, and obtaining a comparison result;

[0018] S22, according to the comparison result, judging whether an acceleration change feature that is inconsistent with the overall low-speed motion trend of the mobile platform appears in the inertial measurement unit data detected by the inertial measurement unit, and the displacement direction of the mobile platform indicated by the acceleration change feature is inconsistent with the vertical motion image data output by the visual system, and marking the acceleration change feature as an invalid vibration feature mode;

[0019] S23, storing the identified one or more invalid vibration feature modes to constitute a vibration suppression mode library.

[0020] Further, the step of constructing the vibration suppression mode library and configuring a conditional trigger applying the vibration suppression mode library, wherein the vibration suppression mode library comprises a plurality of invalid vibration feature modes, the invalid vibration feature mode indicates that the inertial measurement unit detects an acceleration change feature in the inertial measurement unit data that is inconsistent with the overall low-speed motion trend of the mobile platform, comprises:

[0021] S221, periodically acquiring the vertical acceleration data output by the inertial measurement unit of the UAV and the vertical motion image data output by the visual system of the UAV;

[0022] S222, according to the vertical acceleration data output by the inertial measurement unit, performing frequency analysis to obtain the frequency component and energy distribution of the vertical acceleration data output by the inertial measurement unit; according to the vertical motion image data output by the visual system, performing motion trend analysis to obtain the low-frequency motion trend of the mobile platform;

[0023] S223, according to the frequency component and energy distribution of the inertial measurement unit data and the low-frequency motion trend of the mobile platform, judging whether there is an extreme value exceeding a preset energy threshold in the energy distribution of the vertical acceleration data and the vertical motion of the visual system does not show the corresponding vertical motion;

[0024] S224, if the extreme value exists, extracting the feature of the extreme value in the vertical acceleration data as the current identified acceleration change feature, and marking the acceleration change feature as an invalid vibration feature mode.

[0025] Further, the confidence threshold is set based on a visual marker completeness obtained by the visual system.

[0026] The visual marker completeness indicates one or more of a percentage of the number of visual feature points detected by the visual system to the total number of feature points of the mobile platform, and a number of frames in which the visual system continuously identifies a set number of feature points on the mobile platform.

[0027] Further, the step of instructing the UAV not to execute the vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform when the vertical vibration of the mobile platform is determined, and maintaining the preset landing posture of the UAV, comprises:

[0028] S61, when the vertical vibration of the mobile platform is determined, reducing the weight of the vertical acceleration data output by the current inertial measurement unit in the attitude and height control calculation of the UAV;

[0029] S62, instructing the UAV not to execute the rapid vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform, and maintaining the preset landing posture of the UAV.

[0030] Further, the step of instructing the UAV not to execute the rapid vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform when the vertical vibration of the mobile platform is determined, and maintaining the preset landing posture of the UAV, further comprises:

[0031] S7, when the visual positioning information about the mobile platform obtained by the visual system recovers to the preset confidence threshold, calibrating the current estimated position and attitude of the UAV using the visual positioning information output by the recovered visual system.

[0032] Further, the step of calibrating the current estimated position and attitude of the UAV using the visual positioning information output by the recovered visual system when the visual positioning information about the mobile platform obtained by the visual system recovers to the preset confidence threshold, comprises:

[0033] S71, when the visual positioning information about the mobile platform obtained by the visual system recovers to the preset confidence threshold, obtaining the recovered visual positioning information;

[0034] S72, calculating the deviation between the recovered visual positioning information and the estimated relative position and attitude of the UAV relative to the mobile platform according to the recovered visual positioning information and the estimated relative position and attitude.

[0035] S73, determining calibration parameters according to the deviation and the confidence of the recovered visual positioning information;

[0036] S74, gradually adjusting the estimated position and attitude of the UAV according to the calibration parameters within a preset time window.

[0037] Further, the step of determining calibration parameters according to the deviation and the confidence of the recovered visual positioning information comprises:

[0038] S731, determining an initial adjustment weight according to the magnitude of the deviation;

[0039] S732, correcting the initial adjustment weight according to the confidence of the recovered visual positioning information to obtain final calibration parameters.

[0040] Further, the step of gradually adjusting the estimated position and attitude of the UAV according to the calibration parameters within a preset time window comprises:

[0041] S741, generating an intermediate target point according to the current estimated relative position and attitude of the UAV relative to the mobile platform, the recovered visual positioning information and the calibration parameters within the preset time window;

[0042] S742, causing the UAV to sequentially follow the intermediate target point, so that the relative position and attitude of the UAV relative to the mobile platform smoothly transition from the estimated relative position and attitude to the position and attitude consistent with the recovered visual positioning information.

[0043] As a second aspect of the present application, a UAV take-off and landing control system is provided for realizing stable following of a UAV to a target platform and precise landing, and the system is applied to a UAV and a mobile platform configured with an inertial measurement unit and a visual system, and the system comprises:

[0044] A vibration suppression mode library construction module is configured to construct a vibration suppression mode library and a condition trigger for applying the vibration suppression mode library, wherein the vibration suppression mode library comprises a plurality of invalid vibration feature modes, and the invalid vibration feature modes indicate that the acceleration change feature in the inertial measurement unit data obtained by the inertial measurement unit of the mobile platform is inconsistent with the overall low-speed motion trend of the mobile platform.

[0045] a vibration suppression mode library activation module configured to activate a vibration suppression mode when it is determined that the distance between the UAV and the mobile platform is lower than a preset distance threshold and the visual positioning information about the mobile platform obtained by the visual system is lower than a preset reliability threshold, the vibration suppression mode indicating that the UAV is instructed not to execute the corresponding generated rapid vertical attitude or height adjustment instruction triggered by the vertical vibration of the mobile platform in the current operating state and the UAV maintains a preset landing form;

[0046] a comparison analysis module configured to, in the vibration suppression mode, receive and analyze the vertical acceleration data output by the inertial measurement unit in real time, and compare the current vertical acceleration data output by the inertial measurement unit with the invalid vibration characteristic mode in the vibration suppression mode library in real time;

[0047] a comparison judgment module configured to determine that the current vertical acceleration data output by the inertial measurement unit indicates the vertical vibration of the mobile platform when it is determined that the current vertical acceleration data output by the inertial measurement unit meets a preset matching degree threshold;

[0048] a UAV landing execution module configured to, in the case of determining the vertical vibration of the mobile platform, instruct the UAV not to execute the corresponding generated rapid vertical attitude or height adjustment instruction triggered by the vertical vibration of the mobile platform and maintain a preset landing form.

[0049] The UAV landing control system of the present application comprises a vibration suppression mode library construction module, a vibration suppression mode library activation module, a comparison analysis module, a comparison judgment module and a UAV landing execution module. By constructing the vibration suppression mode library and configuring the condition trigger for applying the vibration suppression mode library, the vibration suppression mode is activated when it is determined that the distance between the UAV and the mobile platform is lower than a preset distance threshold and the visual positioning information about the mobile platform obtained by the visual system is lower than a preset reliability threshold. In this mode, the vertical acceleration data output by the inertial measurement unit is received and analyzed in real time, and the current vertical acceleration data output by the inertial measurement unit is compared with the invalid vibration characteristic mode in the vibration suppression mode library in real time. When a preset matching degree threshold is met, it is determined that the mobile platform is vertically vibrated. The UAV is instructed not to execute the corresponding generated rapid vertical attitude or height adjustment instruction triggered by the vertical vibration of the mobile platform, and the UAV maintains a preset landing form. This method identifies and suppresses invalid vibration, maintains a stable landing form when visual information is unreliable, and effectively improves the landing stability of the UAV in a complex environment.

[0050] For better understanding and implementation, the present application is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a flowchart of a UAV take-off and landing control method in the embodiment;

[0052] Figure 2 is a flowchart of step S2 in the UAV take-off and landing control method in the embodiment;

[0053] Figure 3 is a flowchart of step S6 in the UAV take-off and landing control method in the embodiment;

[0054] Figure 4 is a flowchart of the UAV take-off and landing control method in the embodiment, which includes step S7;

[0055] Figure 5 is a flowchart of step S7 in the UAV take-off and landing control method in the embodiment;

[0056] Figure 6 is a system structure block diagram of a UAV take-off and landing control system in the embodiment.

[0057] BRIEF DESCRIPTION OF DRAWINGS: 101, vibration suppression mode library construction module; 102, vibration suppression mode library activation module; 103, comparison analysis module; 104, comparison judgment module; 105, UAV landing execution module. DETAILED DESCRIPTION

[0058] In order to better illustrate the present application, the present application will be further described in detail below with reference to the accompanying drawings.

[0059] It should be clear that, in order to make the purposes, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all the embodiments. The components of the embodiments of the present disclosure described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the claimed present disclosure, but only represents selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present disclosure.

[0060] The following is described with one specific embodiment, in which:

[0061] First, as shown in Figure 1 , a UAV take-off and landing control method is provided, comprising:

[0062] S1, providing a UAV and a mobile platform configured with an inertial measurement unit and a vision system;

[0063] S2, constructing a vibration suppression mode library including a plurality of invalid vibration characteristic patterns indicating that the inertial measurement unit detects an acceleration change characteristic in the obtained inertial measurement unit data that does not match a low-speed motion trend of the mobile platform as a whole;

[0064] S3, when it is determined that the distance between the UAV and the mobile platform is lower than a preset distance threshold, and the visual positioning information about the mobile platform obtained by the vision system is lower than a preset confidence threshold, a vibration suppression mode is enabled, which indicates that the UAV and the mobile platform in the current running state trigger the condition trigger to apply the vibration suppression mode library;

[0065] S4, in the vibration suppression mode, real-time receiving and analyzing the vertical acceleration data output by the inertial measurement unit, and comparing the current vertical acceleration data output by the inertial measurement unit with the invalid vibration characteristic patterns in the vibration suppression mode library in real time;

[0066] S5, when it is determined that the current vertical acceleration data output by the inertial measurement unit and the invalid vibration characteristic pattern satisfy a preset matching degree threshold, it is determined that the current vertical acceleration data output by the inertial measurement unit indicates the vertical vibration of the mobile platform;

[0067] S6, when it is determined that the vertical vibration of the mobile platform, the UAV is instructed not to execute the vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform, and the UAV maintains a preset landing form.

[0068] Firstly, the present application provides a UAV take-off and landing control method, which aims to solve the control problem caused by platform vibration and visual information uncertainty when the UAV takes off and lands on the mobile platform. By constructing a vibration suppression mode library and dynamically adjusting the control strategy combined with the visual information confidence, the stability of take-off and landing is improved.

[0069] In the present method, the inertial measurement unit refers to a sensor capable of measuring the acceleration and angular velocity of an object, which can be realized by a micro-electro-mechanical system inertial sensor, a fiber-optic gyroscope or a laser gyroscope. It is mainly used to obtain the motion state information of the mobile platform, including its vertical acceleration change. The vision system refers to a system that obtains image information through an optical sensor and processes it to realize positioning and recognition functions. It is mainly used to obtain the visual positioning information of the UAV relative to the mobile platform.

[0070] By combining the pre-constructed vibration suppression mode library with the condition trigger mechanism based on the distance between the UAV and the mobile platform and the confidence of the visual system, the vertical vibration of the mobile platform can be effectively identified and suppressed when the UAV approaches the mobile platform and the visual positioning information is unreliable during the critical landing stage, thereby improving the stability of the UAV landing on the complex mobile platform.

[0071] Firstly, a mobile platform configured with an inertial measurement unit and a UAV configured with a visual system are provided to lay the foundation for subsequent data collection and control. Before the UAV begins to land, the system pre-constructs a vibration suppression mode library and stores a plurality of invalid vibration feature modes therein. These modes are pre-identified acceleration change characteristics that do not match the overall low-speed motion trend of the mobile platform, which represent the vertical vibration that the mobile platform may generate during operation. At the same time, the system configures a condition trigger for applying the vibration suppression mode library, so that the vibration suppression function can be activated under certain conditions. When the distance between the UAV and the mobile platform is below a preset distance threshold, and the visual positioning information about the mobile platform obtained by the visual system is below a preset confidence threshold, it is determined that the current environment poses a challenge to the accurate landing of the UAV, at which time the vibration suppression mode is enabled. In the vibration suppression mode, the UAV receives and analyzes the vertical acceleration data output by the inertial measurement unit of the mobile platform in real time. These real-time data are compared with the invalid vibration feature modes in the vibration suppression mode library in real time, and the system can determine whether the current vertical acceleration data output by the inertial measurement unit meets a preset matching degree threshold. Once the matching degree threshold is met, the system determines that the current vertical acceleration data output by the inertial measurement unit indicates the vertical vibration of the mobile platform. Once the vertical vibration of the mobile platform is determined, suppression measures are immediately taken, and the UAV is instructed not to execute the rapid vertical attitude or height adjustment instructions corresponding to the vertical vibration. This means that even if the inertial measurement unit reports a severe vertical acceleration change, the UAV will not blindly make compensatory adjustments.

[0072] Through the above technical solutions, the present application can effectively solve the challenges faced by the UAV during take-off and landing on the mobile platform. Firstly, by constructing the vibration suppression mode library and combining the condition trigger mechanism, the present application can intelligently identify and suppress invalid inertial measurement unit data caused by the vertical vibration of the mobile platform, avoiding unnecessary rapid vertical attitude or height adjustments of the UAV to these interference signals. Secondly, during the critical landing stage when the confidence of the visual positioning information is low, the present application can switch to the vibration suppression mode to effectively deal with the problem of intermittent loss or jump of visual information, ensuring that the UAV can maintain a stable landing trajectory when the visual information is unreliable. Finally, the UAV can more accurately follow the mobile platform and achieve smooth landing.

[0073] In this embodiment, as shown in Figure 2 The step of constructing the vibration suppression mode library and configuring the condition trigger of applying the vibration suppression mode library, wherein the vibration suppression mode library comprises a plurality of invalid vibration feature modes, includes:

[0074] S21, before receiving the landing request information sent by the UAV to the mobile platform and when the mobile platform passes through the joint, comparing the vertical acceleration data output by the inertial measurement unit with the vertical motion image data output by the visual system, and obtaining a comparison result;

[0075] S22, according to the comparison result, judging whether an acceleration change feature inconsistent with the overall low-speed motion trend of the mobile platform appears in the inertial measurement unit data detected and obtained by the inertial measurement unit, and the displacement direction of the mobile platform indicated by the acceleration change feature is inconsistent with the vertical motion image data output by the visual system, and marking the acceleration change feature as an invalid vibration feature mode;

[0076] S23, storing the identified one or more invalid vibration feature modes to form a vibration suppression mode library.

[0077] Before the UAV sends the landing request information to the mobile platform and when the mobile platform passes through the joint, the vertical acceleration data output by the inertial measurement unit is compared with the vertical motion image data output by the visual system, so as to obtain a comparison result. This comparison process takes advantage of the complementarity of two different types of sensor data: the inertial measurement unit is sensitive to instantaneous acceleration change, while the visual system can provide relatively stable image information reflecting the overall low-speed motion of the platform. Based on this comparison result, it can be judged whether there is an acceleration change feature inconsistent with the overall low-speed motion trend of the mobile platform in the inertial measurement unit data, and the displacement direction of the mobile platform indicated by the feature is inconsistent with the vertical motion image data output by the visual system. This inconsistency is the key criterion for identifying invalid vibration feature modes, indicating that the vertical vibration change detected by the inertial measurement unit is not caused by the real displacement of the platform as a whole, but by local vibration or jolt. Once such a feature is identified, it will be marked as an invalid vibration feature mode and stored, thereby forming a vibration suppression mode library.

[0078] In this way, the vibration suppression mode library is constructed, so that in the subsequent landing process of the unmanned aerial vehicle, when it is judged that the distance between the unmanned aerial vehicle and the mobile platform is lower than the preset distance threshold and the visual positioning information is lower than the preset reliability threshold, the vibration suppression mode can be enabled. In the vibration suppression mode, the unmanned aerial vehicle can receive and analyze the vertical acceleration data output by the inertial measurement unit in real time, and compare it with the invalid vibration feature mode in the vibration suppression mode library in real time. When the current vertical acceleration data output by the inertial measurement unit meets the preset matching degree threshold with the invalid vibration feature mode, the system can accurately judge that the current vertical acceleration data output by the inertial measurement unit indicates the vertical vibration of the mobile platform. Based on this judgment, the unmanned aerial vehicle is instructed not to execute the rapid vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform, and the unmanned aerial vehicle maintains the preset landing mode.

[0079] In this scheme, by using the data of two different types of sensors, i.e. the inertial measurement unit and the visual system, at a specific time when the mobile platform passes through the joint or other places where vertical vibration may occur, the high-frequency acceleration change characteristics caused by local vibration rather than overall motion can be accurately identified in the inertial measurement unit data. This identification method based on multi-source data comparison avoids the misjudgment that may exist in single sensor data, and improves the accuracy of invalid vibration feature mode identification. These identified invalid vibration feature modes are stored to construct a vibration suppression mode library, which can be used by the unmanned aerial vehicle in the subsequent landing process based on reliable mode library data.

[0080] In this embodiment, the step of judging, according to the comparison result, that the acceleration change characteristics in the inertial measurement unit data detected by the inertial measurement unit of the mobile platform do not match the overall low-speed motion trend of the mobile platform, and that the displacement direction of the mobile platform indicated by the acceleration change characteristics is inconsistent with the vertical motion image data output by the visual system, and marking the acceleration change characteristics as an invalid vibration feature mode, specifically includes:

[0081] S221, periodically acquiring the vertical acceleration data output by the inertial measurement unit of the unmanned aerial vehicle and the vertical motion image data output by the visual system of the unmanned aerial vehicle;

[0082] S222, performing frequency analysis on the vertical acceleration data output by the inertial measurement unit to obtain the frequency components and energy distribution of the vertical acceleration data output by the inertial measurement unit; performing motion trend analysis on the vertical motion image data output by the visual system to obtain the low-frequency motion trend of the mobile platform;

[0083] S223, judging whether there is an extreme value in the energy distribution of the vertical acceleration data exceeding a preset energy threshold and the vertical motion image data of the vision system does not show corresponding vertical motion according to the frequency component and energy distribution of the inertial measurement unit data and the low-frequency motion trend of the mobile platform;

[0084] S224, if so, extracting the feature of the extreme value in the vertical acceleration data as the current identified acceleration change feature and marking the acceleration change feature as an invalid vibration feature mode.

[0085] By periodically acquiring the vertical acceleration data output by the inertial measurement unit of the mobile platform and the vertical motion image data output by the vision system of the unmanned aerial vehicle, the real-time and synchronization of data acquisition are ensured, which lays a foundation for subsequent refined analysis. Further, by frequency analysis on the vertical acceleration data of the inertial measurement unit, the frequency component and energy distribution thereof can be accurately obtained, so as to effectively separate the vertical vibration from the low-frequency motion. By motion trend analysis on the vertical motion image data output by the vision system, the real low-frequency motion trend of the mobile platform can be obtained, which provides a key external reference for judging whether the high-frequency component in the inertial measurement unit data is invalid vibration. Thus, by comprehensively comparing the high-frequency energy of the inertial measurement unit data and whether the corresponding vertical motion is shown in the vision system data, whether there is a case that the high-frequency energy in the vertical acceleration data exceeds a preset energy threshold and the vision system does not show corresponding vertical motion can be accurately judged. This double-source data cross-validation mechanism enables the system to effectively distinguish between the actual low-speed motion of the mobile platform and the instantaneous vertical vibration caused by factors such as uneven ground. If it is judged that such a case exists, the high-frequency feature is extracted and marked as an invalid vibration feature mode, so as to avoid the unmanned aerial vehicle making false attitude or height adjustment for these vibrations that should not be followed, and ensure the stability of the unmanned aerial vehicle taking off and landing on the mobile platform.

[0086] In one specific example, the vertical acceleration data outputted by the inertial measurement unit of the mobile platform can be periodically acquired at a frequency of 100 Hz, while the vertical motion video data outputted by the vision system of the UAV can be acquired at a frame rate of 30 frames per second. According to the vertical acceleration data outputted by the inertial measurement unit, a fast Fourier transform (FFT) can be used to perform frequency analysis, thereby obtaining the frequency components and corresponding energy distribution in the range of 0-50 Hz. At the same time, according to the vertical motion video data outputted by the vision system, the low-frequency motion trend of the mobile platform in the range of 0-5 Hz can be obtained. According to the energy distribution of the components with a frequency higher than 10 Hz in the inertial measurement unit (IMU) data, and comparing it with a preset energy threshold, which can be an empirical value determined by experimental calibration or based on historical data statistical analysis. At the same time, it is judged whether the vertical motion video data of the vision system shows significant vertical motion with a frequency higher than 10 Hz in the corresponding time period. If the inertial measurement unit data shows that the frequency energy exceeds the threshold, while the vision system does not show the corresponding vertical motion, the characteristics of the inertial measurement unit vertical acceleration data with a frequency higher than 10 Hz and energy exceeding the threshold are extracted as the current identified acceleration change characteristics, and are marked as invalid vibration characteristic patterns, so that the subsequent vibration suppression module can identify and ignore these characteristics.

[0087] In some of the foregoing embodiments, it is mentioned that when the distance between the UAV and the mobile platform is lower than a preset distance threshold, and the visual positioning information obtained by the vision system is lower than a preset confidence threshold, the vibration suppression mode is enabled. The preset confidence threshold can be a fixed empirical value, for example, 0.7, so that the reliability of the visual positioning information can be used to determine whether to enable the vibration suppression mode.

[0088] In the present embodiment, the confidence threshold is preferably set based on the visual marker completeness obtained by the vision system.

[0089] The visual marker completeness indicates one or more of the percentage of the number of visual feature points detected by the vision system to the total number of feature points of the mobile platform, and the number of frames in which the vision system continuously identifies a set number of feature points on the mobile platform.

[0090] The confidence threshold refers to a criterion for judging the reliability of the visual positioning information, and its purpose is to provide a basis for the system to judge whether the visual data is usable.

[0091] The visual marker completeness is a quantitative indicator indicating the clarity and completeness of the visual marker identified by the vision system, and its purpose is to reflect the quality of the visual positioning information.

[0092] In the scheme, the confidence threshold is dynamically adjusted, so that the UAV can more intelligently evaluate the reliability of the visual positioning information.

[0093] In some specific examples, the vision system on the UAV can configure an image processor that is capable of analyzing the mobile platform images acquired from the on-board camera in real time. During the image processing, the feature points on the visual marker can be first identified by a feature extraction algorithm, such as the Scale-Invariant Feature Transform (SIFT) or Speeded Up Robust Features (SURF) algorithm. In advance, the total number of feature points that the mobile platform visual marker should contain in the ideal state can be determined. One way to measure the completeness of the visual marker can be to calculate the percentage of the number of currently detected visual feature points to the total number of mobile platform feature points. For example, if the total number of mobile platform feature points is 100, and 85 are currently detected, the percentage is 85%. At the same time, the vision system can continuously track these feature points and record the number of frames in which a set number of feature points (e.g., at least 80% of the feature points) on the mobile platform are continuously identified. When the completeness of the visual marker (e.g., the percentage of feature points) is high and the number of continuously identified frames is long, the confidence threshold can be dynamically set to a higher value, such as 0.8. Conversely, when the completeness of the visual marker is low or the number of continuously identified frames is short, the confidence threshold can be set to a lower value, such as 0.6. In this way, when the UAV judges whether the visual positioning information is reliable, it will adaptively adjust according to the actual status of the visual marker, so as to more accurately determine whether to enable the vibration suppression mode.

[0094] In the embodiment, as shown in Figure 3 The step of judging that, under the vertical vibration of the mobile platform, the UAV is instructed not to execute the vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform, and the UAV maintains the preset landing posture, includes:

[0095] S61, under the vertical vibration of the mobile platform, reducing the weight of the vertical acceleration data output by the inertial measurement unit in the attitude and height control calculation of the UAV;

[0096] S62, instructing the UAV not to execute the rapid vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform, and the UAV maintains the preset landing posture.

[0097] By fine processing of the inertial measurement unit data and optimization of the UAV control strategy, stable landing under the vertical vibration of the mobile platform is realized.

[0098] Specifically, when the system determines that the mobile platform is experiencing vertical vibration, which is usually based on the result of comparing the vertical acceleration data output by the inertial measurement unit with the pre-constructed invalid vibration feature pattern, it indicates that the current inertial measurement unit data contains a large amount of noise components that should not be followed by the UAV. In this case, the weight of the vertical acceleration data output by the current inertial measurement unit in the attitude and height control calculation of the UAV is reduced. This means that the influence of the inertial measurement unit data on the decision of the UAV control system is weakened, effectively filtering out the instantaneous, violent and useless acceleration change information caused by vertical vibration.

[0099] In a specific example, when the UAV control system determines that the mobile platform is experiencing vertical vibration through comparison analysis, for example, when the vertical acceleration data output by the inertial measurement unit matches the invalid vibration feature pattern in the vibration suppression pattern library to reach a preset threshold, the control system can dynamically adjust the parameters of its state estimation and control loop. Specifically, for reducing the weight of the vertical acceleration data output by the current inertial measurement unit in the attitude and height control calculation of the UAV, an adaptive Kalman filtering algorithm can be used. In this algorithm, when vertical vibration is detected, the gain related to the inertial measurement unit vertical acceleration measurement noise covariance matrix in the Kalman filter can be reduced in real time, or the terms related to vertical position and velocity in the state estimation covariance matrix can be increased, thereby reducing the contribution of inertial measurement unit data to the state estimation of the UAV.

[0100] Through the above technical solutions, the problem that the UAV is difficult to land stably under the vertical vibration of the mobile platform can be effectively solved. Specifically, by reducing the weight of the vertical acceleration data output by the inertial measurement unit in the attitude and height control calculation of the UAV, the interference of noise caused by vertical vibration on the UAV control system can be effectively suppressed, and unnecessary violent attitude or height adjustment of the UAV due to false response to invalid vibration can be avoided. At the same time, by instructing the UAV not to execute the rapid adjustment instruction generated by the vertical vibration and maintaining the preset landing shape, it is ensured that the UAV can still maintain a smooth and controllable descent trajectory when disturbed by vibration, thereby significantly improving the stability of the UAV landing in a complex dynamic environment and reducing the risk of landing failure.

[0101] In the embodiment, as shown in Figure 4 After the step of determining that the mobile platform is experiencing vertical vibration, the UAV is instructed not to execute the rapid vertical attitude or height adjustment instruction generated by the vertical vibration of the mobile platform, and the UAV maintains the preset landing shape, the method further includes:

[0102] S7, when the visual positioning information obtained by the vision system about the mobile platform recovers to a preset confidence threshold, calibrating the estimated position and attitude of the current UAV using the recovered visual positioning information output by the vision system.

[0103] By further introducing the mechanism of position and attitude calibration based on the positioning information recovered by the vision system on the basis of the unmanned aerial vehicle suppressing the vertical vibration of the mobile platform, the problem of accumulated error generated by long-term reliance of the unmanned aerial vehicle on the inertial measurement unit for estimation is solved. Specifically, in the process of the unmanned aerial vehicle maintaining the preset landing posture without following the vertical vibration of the mobile platform, although the attitude instability caused by the vibration is avoided, the position and attitude estimation of the inertial measurement unit inside the unmanned aerial vehicle will inevitably drift and accumulate error after a long time of estimation. When the external environmental conditions improve, the vision system of the unmanned aerial vehicle can re-identify the mobile platform stably, and the confidence of the visual positioning information output by the vision system reaches a preset confidence threshold. At this time, the system will use these recovered visual positioning information with high confidence to compare with the position and attitude of the unmanned aerial vehicle estimated by the inertial measurement unit. Through this comparison, the deviation between the estimated value and the true value can be accurately calculated. Subsequently, the system will correct the estimated position and attitude of the unmanned aerial vehicle according to this deviation.

[0104] Specifically, step S7 is further explained as follows. In the embodiment, as shown in Figure 5 the step of calibrating the estimated position and attitude of the current unmanned aerial vehicle using the recovered visual positioning information output by the vision system when the visual positioning information obtained by the vision system about the mobile platform recovers to a preset confidence threshold, comprises:

[0105] S71, when the visual positioning information obtained by the vision system about the mobile platform recovers to a preset confidence threshold, obtaining the recovered visual positioning information;

[0106] S72, calculating the deviation between the recovered visual positioning information and the estimated relative position and attitude of the unmanned aerial vehicle relative to the mobile platform according to the recovered visual positioning information and the estimated relative position and attitude;

[0107] S73, determining the calibration parameter according to the deviation and the confidence of the recovered visual positioning information;

[0108] S74, gradually adjusting the estimated position and attitude of the unmanned aerial vehicle according to the calibration parameter within a preset time window.

[0109] Through the refined calibration strategy, the calibration problem that may occur after the visual positioning information recovers is solved, thereby improving the flight stability.

[0110] Specifically, when the vision system obtains the visual positioning information about the mobile platform and recovers to a pre-set confidence threshold, the system first acquires these recovered visual positioning information. This step ensures that the calibration process will only be triggered when the visual information is reliable enough, avoiding introducing new errors due to the use of low-quality data. Subsequently, the system calculates the deviation between the recovered visual positioning information and the current estimated relative position and attitude of the UAV with respect to the mobile platform. This deviation quantifies the positioning error that the UAV can accumulate during the period when visual information is unavailable. Further, the core of the scheme lies in intelligently determining the calibration parameters according to the deviation and the confidence of the recovered visual positioning information. This means that the strength and manner of calibration are no longer fixed, but dynamically adjusted according to the error size and the reliability of the visual information. On this basis, in order to ensure the smoothness of the calibration process, the present scheme gradually adjusts the estimated position and attitude of the UAV within a pre-set time window according to the determined calibration parameters. This gradual adjustment avoids the instantaneous jump of the position and attitude of the UAV, enabling the UAV to smoothly transition from its estimated state to the accurate state indicated by the recovered visual information.

[0111] In one specific example, the system obtains the recovered visual positioning information when the visual system of the UAV regains the visual positioning information about the mobile platform and the confidence of the information reaches a pre-set confidence threshold, e.g., when the visual system successfully identifies and stably tracks more than a certain number of visual feature points on the mobile platform, or the positioning error of consecutive multiple frames is lower than a pre-set value. Subsequently, the UAV control system calculates the deviation between the current estimated relative position and attitude of the UAV with respect to the mobile platform and the recovered visual positioning information, which can be a six-degree-of-freedom (position deviation in X, Y, Z directions and attitude deviation in roll, pitch, yaw angles) vector obtained by directly comparing the two sets of pose data. On this basis, the system dynamically determines the calibration parameter according to the calculated deviation and the confidence of the recovered visual positioning information. For example, a non-linear function or lookup table mechanism can be designed to take the absolute value of the deviation and the confidence of the visual positioning information as input and output a calibration gain between 0 and 1. When the deviation is large and the confidence is high, the calibration gain can be set relatively large to achieve faster calibration; when the confidence is low, even if the deviation is large, the calibration gain will be limited to a small value to avoid excessive calibration due to unreliable information. Finally, in order to ensure the smoothness of the calibration process, the system gradually adjusts the estimated position and attitude of the UAV within a pre-set time window according to the determined calibration parameter. For example, the calibration amount can be decomposed into multiple small steps, and within the pre-set time window, a step of calibration amount is applied every control cycle, or a smooth trajectory is generated to gradually transition the position and attitude of the UAV from the current estimated value to the target value indicated by the recovered visual information. This approach can effectively avoid sudden displacement or attitude change of the UAV during calibration, thereby ensuring flight stability.

[0112] In the present embodiment, the step of determining the calibration parameter according to the deviation and the confidence of the recovered visual positioning information comprises:

[0113] S731, determining an initial adjustment weight according to the magnitude of the deviation;

[0114] S732, correcting the initial adjustment weight according to the confidence of the recovered visual positioning information to obtain the final calibration parameter.

[0115] The magnitude of the deviation refers to a quantitative representation of the difference between the estimated position and attitude of the UAV and the recovered visual positioning information, which aims to quantify the degree of deviation between the current state and the target state of the UAV;

[0116] The initial adjustment weight refers to the calibration intensity factor preliminarily set according to the magnitude of the deviation, which aims to reflect that the larger the deviation, the larger the amount of adjustment required in theory.

[0117] With a specific example, when the UAV needs to calibrate its estimated position and attitude relative to the mobile platform, first, the difference data between the current estimated position and attitude of the UAV and the recovered visual positioning information can be calculated and weighted to obtain a deviation amplitude value. Then, according to the deviation amplitude value, an initial adjustment weight can be determined. For example, a piecewise function can be preset, when the deviation amplitude is small, the initial adjustment weight can be set to a small value; when the deviation amplitude is moderate, it is set to a moderate value; when the deviation amplitude is large, it is set to a large value. Subsequently, in order to modify the initial adjustment weight, the system can obtain the confidence of the recovered visual positioning information. For example, the visual system can output a confidence score, which can be calculated based on the number of recognized visual feature points, the uniformity of the distribution of these feature points in the image, and the stability of feature point matching between consecutive frames. This confidence score can be a number between 0 and 1, where 1 represents high confidence and 0 represents low confidence. Then, the initial adjustment weight can be modified using the confidence score. Specifically, the initial adjustment weight can be multiplied by the confidence score, or a weighted average model can be used. For example, if the initial adjustment weight is 0.8 and the confidence of the visual positioning information is 0.5, then the final calibration parameter can be calculated as 0.8 multiplied by 0.5. In this way, when the visual positioning information is not highly reliable, even if the deviation amplitude is large, the final calibration parameter will be appropriately reduced, thereby avoiding excessive adjustment amplitude. Conversely, if the confidence is high, for example, 0.9, then the final calibration parameter will be 0.8 multiplied by 0.9, so that the calibration intensity is closer to the initial adjustment weight, in order to fully utilize reliable visual information. In this way, the determination process of the final calibration parameter can dynamically adapt to the quality of the visual positioning information, ensuring the smoothness of the calibration.

[0118] In the embodiment, the step of gradually adjusting the estimated position and attitude of the UAV according to the calibration parameter within the preset time window comprises:

[0119] S741, generating an intermediate target point according to the current estimated relative position and attitude of the UAV relative to the mobile platform, the recovered visual positioning information, and the calibration parameter within the preset time window;

[0120] S742, causing the UAV to follow the intermediate target point in sequence, so that the relative position and attitude of the UAV and the mobile platform smoothly transition from the estimated relative position and attitude to the position and attitude consistent with the recovered visual positioning information.

[0121] The intermediate target points are a series of discrete or continuous transition points generated between the current estimated position and attitude of the UAV and the position and attitude indicated by the recovered visual positioning information, and these points constitute a series of trajectory nodes that the UAV needs to reach in sequence during the calibration process. The purpose is to divide the large-scale position and attitude adjustment into multiple small-scale and controllable adjustment steps, so as to avoid the sudden change of the UAV motion.

[0122] By generating a series of intermediate target points within a preset time window according to the current estimated relative position and attitude of the UAV relative to the mobile platform, the recovered visual positioning information and the calibration parameters, the position and attitude calibration process of the UAV is divided into multiple controllable and small-scale adjustment stages. It is because of the introduction of these intermediate target points and the UAV following these target points in sequence that the relative position and attitude of the UAV and the mobile platform can be smoothly transitioned from the estimated relative position and attitude to the position and attitude consistent with the recovered visual positioning information.

[0123] In a specific example, when the visual positioning information obtained by the visual system about the mobile platform is recovered to a preset confidence threshold, the position and attitude calibration process of the UAV control system is started. Specifically, within a preset time window, for example, set to 2 seconds, the control system generates a series of intermediate target points according to the current estimated relative position and attitude of the UAV relative to the mobile platform calculated by the inertial navigation, and the visual positioning information recovered at this moment, and combines the previously determined calibration parameters. For example, assuming that N intermediate target points need to be generated within the preset time window, the position and attitude of the kth intermediate target point can be calculated as: P_k = P_imu + (P_vis - P_imu) * (k / N) * α. Where P_imu represents the estimated position and attitude, P_vis represents the visual positioning information, and k increases from 1 to N. In this way, as k increases, the intermediate target points gradually approach the position and attitude indicated by the visual positioning information from the estimated position and attitude, and the speed and degree of approximation are controlled by the calibration parameter α. Subsequently, the UAV flight control system follows these generated intermediate target points in sequence. This means that the UAV will not directly jump to the final position and attitude indicated by the visual positioning information, but will adjust the current position and attitude to the next intermediate target point at each time step. For example, the flight controller will calculate the attitude and thrust command required to reach the next intermediate target point from the current position, and execute it smoothly. In this way, the relative position and attitude of the UAV and the mobile platform can gradually transition from the estimated relative position and attitude to the position and attitude consistent with the recovered visual positioning information in a controlled and smooth manner, thereby avoiding the body shaking or attitude instability caused by sudden calibration.

[0124] Secondly, asFigure 6 As shown, a UAV landing control system 100 is provided for realizing stable following of a UAV to a target platform and realizing precise landing, and the system is applied to a UAV and a mobile platform configured with an inertial measurement unit and a vision system, and the system comprises:

[0125] a vibration suppression mode library construction module 101 configured to construct a vibration suppression mode library and a condition trigger applying vibration suppression mode library, wherein the vibration suppression mode library comprises a plurality of invalid vibration characteristic modes indicating that acceleration change characteristics inconsistent with the overall low-speed motion trend of the mobile platform appear in the obtained inertial measurement unit data detected by the inertial measurement unit of the mobile platform;

[0126] a vibration suppression mode library activation module 102 configured to activate a vibration suppression mode when it is determined that the distance between the UAV and the mobile platform is lower than a preset distance threshold, and the vision positioning information about the mobile platform obtained by the vision system is lower than a preset confidence threshold, wherein the vibration suppression mode indicates that the vibration suppression mode library is applied to the condition trigger in the current running state of the UAV and the mobile platform;

[0127] a comparison analysis module 103 configured to receive and analyze the vertical acceleration data output by the inertial measurement unit in real time in the vibration suppression mode, and compare the current vertical acceleration data output by the inertial measurement unit with the invalid vibration characteristic modes in the vibration suppression mode library in real time;

[0128] a comparison judgment module 104 configured to determine that the current vertical acceleration data output by the inertial measurement unit indicates the vertical vibration of the mobile platform when the current vertical acceleration data output by the inertial measurement unit and the invalid vibration characteristic modes satisfy a preset matching degree threshold;

[0129] a UAV landing execution module 105 configured to instruct the UAV not to execute the rapid vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform when it is determined that the vertical vibration of the mobile platform, and the UAV maintains a preset landing form.

[0130] The unmanned aerial vehicle landing control system 100 in the embodiment includes a vibration suppression mode library construction module 101, a vibration suppression mode library activation module 102, a comparison analysis module 103, a comparison judgment module 104, and an unmanned aerial vehicle landing execution module 105. By constructing the vibration suppression mode library and configuring the condition trigger for applying the vibration suppression mode library, when it is determined that the distance between the unmanned aerial vehicle and the mobile platform is lower than a preset distance threshold, and the visual positioning information about the mobile platform obtained by the visual system is lower than a preset reliability threshold, the vibration suppression mode is activated. In this mode, the vertical acceleration data output by the inertial measurement unit is received and analyzed in real time, the current vertical acceleration data output by the inertial measurement unit is compared with the invalid vibration feature mode in the vibration suppression mode library in real time, and when a preset matching threshold is met, it is determined that the mobile platform is vertically vibrated. The unmanned aerial vehicle is instructed not to execute the vertical attitude or height adjustment instruction corresponding to the vertical vibration of the mobile platform, and the unmanned aerial vehicle maintains a preset landing shape. The method recognizes and suppresses invalid vibration, maintains a stable landing shape when visual information is unreliable, and effectively improves the landing stability of the unmanned aerial vehicle in a complex environment.

[0131] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present disclosure, and are used to illustrate the technical solutions of the present disclosure, rather than limit the same. The protection scope of the present disclosure is not limited thereto. Although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can make modifications or easy changes to the technical solutions recorded in the foregoing embodiments, or easily think of changes or equivalent replacements for some technical features thereof, without departing from the technical scope disclosed by the present disclosure. Such modifications, changes or replacements do not cause the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure, and should be covered within the protection scope of the present disclosure.

Claims

1. A method for controlling the takeoff and landing of an unmanned aerial vehicle (UAV), characterized in that, include: S1. Provides drones and mobile platforms equipped with inertial measurement units and vision systems; S2. Construct a vibration suppression mode library and configure a condition trigger for applying the vibration suppression mode library. The vibration suppression mode library includes multiple invalid vibration feature modes. The invalid vibration feature modes indicate that there are acceleration change features in the inertial measurement unit data obtained by the inertial measurement unit that are inconsistent with the overall low-speed motion trend of the mobile platform. S3. When it is determined that the distance between the UAV and the mobile platform is lower than a preset distance threshold, and the visual positioning information about the mobile platform obtained by the vision system is lower than a preset confidence threshold, the vibration suppression mode is enabled. The vibration suppression mode indicates that the UAV and the mobile platform trigger a condition trigger in the current operating state and apply the vibration suppression mode library. S4. In vibration suppression mode, the vertical acceleration data output by the inertial measurement unit is received and analyzed in real time, and a real-time comparison is performed between the current vertical acceleration data output by the inertial measurement unit and the invalid vibration feature patterns in the vibration suppression mode library; S5. If the vertical acceleration data output by the current inertial measurement unit and the invalid vibration feature patterns meet the preset matching threshold, then the vertical acceleration data output by the current inertial measurement unit is determined to indicate vertical vibration of the mobile platform; S6. Under the condition that the vertical vibration of the mobile platform is determined, the UAV is instructed not to execute the vertical attitude or altitude adjustment commands corresponding to the vertical vibration of the mobile platform, and the UAV maintains the preset landing posture.

2. The unmanned aerial vehicle (UAV) takeoff and landing control method according to claim 1, characterized in that, The steps of constructing a vibration suppression mode library and configuring condition triggers for applying the vibration suppression mode library, wherein the vibration suppression mode library includes multiple invalid vibration feature modes, and the invalid vibration feature mode indicates that the inertial measurement unit data detected by the inertial measurement unit of the mobile platform shows an acceleration change feature that is inconsistent with the overall low-speed motion trend of the mobile platform, include: S21, before receiving the landing request information sent by the UAV to the mobile platform and when the mobile platform passes through the seam, comparing the vertical acceleration data output by the inertial measurement unit with the vertical motion image data output by the vision system, and obtaining the comparison result; S22, based on the comparison result, determining whether the inertial measurement unit data detected by the current inertial measurement unit shows an acceleration change feature that is inconsistent with the overall low-speed motion trend of the mobile platform, and when the displacement direction of the mobile platform indicated by the acceleration change feature is inconsistent with the vertical motion image data output by the vision system, marking the acceleration change feature as an invalid vibration feature mode; S23, storing one or more identified invalid vibration feature modes to form a vibration suppression mode library.

3. The unmanned aerial vehicle (UAV) takeoff and landing control method according to claim 2, characterized in that, The steps of constructing a vibration suppression mode library and configuring condition triggers for applying the vibration suppression mode library, wherein the vibration suppression mode library includes multiple invalid vibration feature modes, and the invalid vibration feature modes indicate acceleration change characteristics in the inertial measurement unit data detected by the inertial measurement unit that are inconsistent with the overall low-speed motion trend of the mobile platform, specifically include: S221, periodically acquiring vertical acceleration data output by the UAV's inertial measurement unit and vertical motion image data output by the UAV's vision system; S222, performing frequency analysis on the vertical acceleration data output by the inertial measurement unit to obtain the vertical acceleration number output by the inertial measurement unit. Based on the frequency components and energy distribution of the data from the inertial measurement unit and the low-frequency motion trend of the mobile platform, the motion trend analysis is performed to obtain the low-frequency motion trend of the mobile platform. S223: Based on the frequency components and energy distribution of the data from the inertial measurement unit and the low-frequency motion trend of the mobile platform, it is determined whether there are extreme values ​​in the energy distribution of the vertical acceleration data that exceed a preset energy threshold and the vertical motion image data of the vision system does not display the corresponding vertical motion. S224: If so, the feature of the extreme value in the vertical acceleration data is extracted as the currently identified acceleration change feature, and the acceleration change feature is marked as an invalid vibration feature mode.

4. The unmanned aerial vehicle (UAV) takeoff and landing control method according to claim 1, characterized in that: The confidence threshold is set based on the visual marker integrity obtained by the vision system; the visual marker integrity indicator is one or more of the following: the percentage of visual feature points detected by the vision system relative to the total number of feature points on the mobile platform and the number of frames in which the vision system continuously identifies a set number of feature points on the mobile platform.

5. The unmanned aerial vehicle (UAV) takeoff and landing control method according to claim 1, characterized in that, The step of instructing the UAV not to execute the vertical attitude or altitude adjustment commands corresponding to the vertical vibration of the mobile platform when it is determined to be vertical vibration of the mobile platform, and maintaining the preset landing posture, includes: S61, reducing the weight of the vertical acceleration data output by the current inertial measurement unit in the attitude and altitude control calculation of the UAV when it is determined to be vertical vibration of the mobile platform; S62, instructing the UAV not to execute the rapid vertical attitude or altitude adjustment commands corresponding to the vertical vibration of the mobile platform, and maintaining the preset landing posture.

6. The unmanned aerial vehicle (UAV) takeoff and landing control method according to claim 1, characterized in that, After the step of determining that the mobile platform is under vertical vibration, the UAV is instructed not to execute the rapid vertical attitude or altitude adjustment command corresponding to the vertical vibration of the mobile platform, and the UAV maintains the preset landing pattern, the method further includes: S7, when the visual positioning information about the mobile platform obtained by the vision system is restored to the preset confidence threshold, the estimated position and attitude of the current UAV are calibrated using the restored visual positioning information output by the vision system.

7. The unmanned aerial vehicle (UAV) takeoff and landing control method according to claim 6, characterized in that, The step of calibrating the estimated position and attitude of the current UAV using the visual positioning information output by the visual system when the visual positioning information about the mobile platform obtained by the visual system is restored to a preset confidence threshold includes: S71, acquiring the restored visual positioning information when the visual positioning information about the mobile platform obtained by the visual system is restored to a preset confidence threshold; S72, calculating the deviation between the restored visual positioning information and the estimated relative position and attitude of the UAV relative to the mobile platform based on the restored visual positioning information and the estimated relative position and attitude of the UAV; S73, determining calibration parameters based on the deviation and the confidence level of the restored visual positioning information; S74, gradually adjusting the estimated position and attitude of the UAV according to the calibration parameters within a preset time window.

8. The unmanned aerial vehicle (UAV) takeoff and landing control method according to claim 7, characterized in that, The step of determining calibration parameters based on the deviation and the confidence level of the recovered visual positioning information includes: S731, determining initial adjustment weights based on the magnitude of the deviation; S732, correcting the initial adjustment weights based on the confidence level of the recovered visual positioning information to obtain the final calibration parameters.

9. The unmanned aerial vehicle (UAV) takeoff and landing control method according to claim 7, characterized in that, The step of gradually adjusting the calculated position and attitude of the UAV according to the calibration parameters within a preset time window includes: S741, generating an intermediate target point within the preset time window based on the currently calculated relative position and attitude of the UAV relative to the mobile platform, the recovered visual positioning information, and the calibration parameters; S742, causing the UAV to follow the intermediate target point in sequence, so that the relative position and attitude of the UAV and the mobile platform smoothly transitions from the calculated relative position and attitude to a position and attitude consistent with the recovered visual positioning information.

10. A drone takeoff and landing control system for achieving stable tracking and precise landing of a drone on a target platform, wherein the system is applied to drones and mobile platforms equipped with inertial measurement units and vision systems, characterized in that... The system includes: a vibration suppression mode library construction module, which is used to construct a vibration suppression mode library and configure conditional triggers for applying the vibration suppression mode library. The vibration suppression mode library includes multiple invalid vibration feature modes, which indicate acceleration changes in the inertial measurement unit data obtained by the inertial measurement unit of the mobile platform that are inconsistent with the overall low-speed motion trend of the mobile platform; and a vibration suppression mode library activation module, which is used to activate a vibration suppression mode when it is determined that the distance between the UAV and the mobile platform is lower than a preset distance threshold, and the visual positioning information about the mobile platform obtained by the vision system is lower than a preset confidence threshold. The vibration suppression mode indicates that the UAV and the mobile platform trigger a conditional trigger to apply vibration suppression in the current operating state. The system includes: a vibration suppression mode library; a comparison and analysis module, which receives and analyzes vertical acceleration data output by the inertial measurement unit in real time under vibration suppression mode, and compares the current vertical acceleration data output by the inertial measurement unit with invalid vibration feature modes in the vibration suppression mode library in real time; a comparison and judgment module, which determines that the vertical acceleration data output by the current inertial measurement unit indicates vertical vibration of the mobile platform when the vertical acceleration data and invalid vibration feature modes meet a preset matching threshold; and a UAV landing execution module, which, when determined to be vertical vibration of the mobile platform, instructs the UAV not to execute the rapid vertical attitude or altitude adjustment commands corresponding to the vertical vibration of the mobile platform, and the UAV maintains a preset landing posture.

Images