Hovering method of aircraft, aircraft and storage medium

Abstract

A hovering method for an aircraft, an aircraft and a storage medium, the method comprising: obtaining a radar image of the aircraft's surrounding environment measured by a radar device, the radar image comprising a first distance angle image corresponding to the first receiving array and a second distance angle image corresponding to the second receiving array (S101); determining a change speed of the aircraft relative to the surrounding environment based on the first distance angle image and the second distance angle image (S102); and performing flight control on the aircraft based on the change speed to achieve hovering (S103).

Description

Technical Field

[0001] The present application relates to the field of flight control technology, and in particular to a hovering method for an aircraft, an aircraft, and a storage medium. Background Art

[0002] At present, in the process of controlling the flight of an aircraft, it is necessary to control the aircraft to hover. The hovering control of the aircraft is usually implemented based on GPS technology. For example, when determining the flight altitude of the aircraft, the coordinate position of the aircraft can be determined by the GPS module installed on the aircraft, and the aircraft can be controlled to hover at a specific position. However, this hovering control based on GPS is greatly affected by the signal. When the GPS signal is weak or unstable, such as when there is no GPS signal indoors, the accuracy of the hovering control is low, which reduces the user experience. Summary of the invention

[0003] The present application provides an aircraft hovering method, an aircraft, and a storage medium to improve the hovering accuracy of the aircraft.

[0004] In a first aspect, an embodiment of the present application provides a hovering method for an aircraft, which is applied to an aircraft, wherein the aircraft is equipped with a radar device, wherein the radar device includes a first receiving array and a second receiving array, and the first receiving array and the second receiving array are arranged at a preset angle; the hovering method includes:

[0005] Acquire a radar image of the aircraft surrounding environment measured by the radar device, wherein the radar image includes a first range angle image corresponding to the first receiving array and a second range angle image corresponding to the second receiving array;

[0006] Determining a changing speed of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image; and

[0007] The aircraft is controlled based on the changing speed to achieve hovering.

[0008] In a second aspect, an embodiment of the present application further provides an aircraft, the aircraft comprising:

[0009] frame;

[0010] A radar device, wherein the radar is mounted on the rack and comprises a first receiving array and a second receiving array, wherein the first receiving array and the second receiving array are arranged at a preset angle;

[0011] Processor and memory;

[0012] The memory is used to store a computer program; the processor is used to execute the computer program and implement the following steps when executing the computer program:

[0013] Acquire a radar image of the aircraft surrounding environment measured by the radar device, wherein the radar image includes a first range angle image corresponding to the first receiving array and a second range angle image corresponding to the second receiving array;

[0014] Determining a changing speed of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image; and

[0015] The aircraft is controlled based on the changing speed to achieve hovering.

[0016] In a third aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor implements the steps of any one of the hovering methods provided in the embodiments of the present application.

[0017] The hovering method, aircraft, and storage medium of the aircraft disclosed in the embodiments of the present application may not be affected by environmental factors, thereby improving the accuracy of hovering control, and further improving the safety of flight and customer experience.

[0018] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 is a structural schematic diagram of an aircraft provided in an embodiment of the present application;

[0021] Figure 2 is a schematic diagram of an antenna structure of a radar device provided in an embodiment of the present application;

[0022] Figure 3 is a schematic diagram of a target observed by a radar device provided in an embodiment of the present application;

[0023] Figure 4 is a schematic diagram of the position of a target in a radar coordinate system provided in an embodiment of the present application;

[0024] Figure 5 is a schematic flow chart of steps of a hovering method for an aircraft provided in an embodiment of the present application;

[0025] Figure 6 is a schematic flow chart of steps of another method for hovering an aircraft provided in an embodiment of the present application;

[0026] Figure 7 It is a schematic block diagram of an aircraft provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] 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 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.

[0028] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0029] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0030] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0031] At present, the hovering of aircraft is generally realized based on GPS technology. Specifically, when the flight altitude of the aircraft is determined, the coordinate position of the aircraft can be determined by the GPS module installed on the aircraft, and the aircraft can be controlled to fly and hover at a specific position corresponding to the coordinate position. Or it can be realized based on optical flow technology. The hovering of aircraft is realized based on optical flow technology. Specifically, the displacement and speed information of the aircraft are determined by collecting images through visual sensors (such as cameras), and the displacement and speed information of the aircraft is controlled based on the displacement and speed information to achieve hovering.

[0032] However, this hover control based on GPS is greatly affected by the signal. When the GPS signal is weak or unstable, such as when there is no GPS signal indoors, the hover control accuracy is low, resulting in poor hovering effect, which may even cause a crash and reduce the user experience. Optical flow technology is greatly affected by light intensity and surrounding textures, so the hover control accuracy is also relatively low.

[0033] To this end, an embodiment of the present application provides a hovering method for an aircraft, an aircraft and a storage medium. The radar device is installed on the aircraft, and the speed of the aircraft is determined by the radar device to achieve hovering. Since the radar device is not affected by the signal quality and the light brightness of the surrounding environment, the hovering accuracy of the aircraft can be improved.

[0034] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0035] See also Figure 1 , Figure 1 The structure of an aircraft 100 provided in an embodiment of the present application is shown. Figure 1 As shown, the aircraft 100 may include a power system, a control system, an airframe 10 , and a radar device 20 .

[0036] The frame 10 may include a fuselage and a landing gear (also referred to as a landing gear). The fuselage may include a center frame and one or more arms connected to the center frame, and the one or more arms extend radially from the center frame. The landing gear is connected to the fuselage to provide support for the aircraft 100 when it lands.

[0037] The radar device 20 can be installed on an aircraft, specifically on a frame 10 of the aircraft 100 , and is used to measure the surrounding environment of the aircraft 100 , such as obstacles, etc., during the flight of the aircraft 100 to ensure the safety of the flight.

[0038] The power system may include one or more electronic speed regulators (ECs), one or more propellers, and one or more motors corresponding to the one or more propellers, wherein the motor is connected between the electronic speed regulator and the propeller, and the motor and the propeller are arranged on the arm of the aircraft 100; the electronic speed regulator is used to receive a driving signal generated by the control system, and provide a driving current to the motor according to the driving signal to control the speed of the motor.

[0039] The motor is used to drive the propeller to rotate, thereby providing power for the flight of the aircraft 100, and the power enables the aircraft 100 to achieve one or more degrees of freedom. In some embodiments, the aircraft 100 can rotate around one or more rotation axes. For example, the above-mentioned rotation axes may include a roll axis, a yaw axis, and a pitch axis. It should be understood that the motor can be a DC motor or a permanent magnet synchronous motor. Alternatively, the motor can be a brushless motor or a brushed motor.

[0040] The control system may include a controller and a sensor system. The controller is used to control the flight of the aircraft 100. For example, the flight of the aircraft 100 may be controlled according to the attitude information measured by the sensor system. It should be understood that the controller may control the aircraft 100 according to pre-programmed instructions. The sensor system is used to measure the attitude information of the aircraft 100, that is, the position information and state information of the aircraft 100 in space, such as three-dimensional position, three-dimensional angle, three-dimensional velocity, three-dimensional acceleration and three-dimensional angular velocity. The sensor system may include, for example, at least one of sensors such as a gyroscope, an ultrasonic sensor, an electronic compass, an inertial measurement unit (IMU), a visual sensor, a global navigation satellite system and a barometer. For example, the global navigation satellite system may be a global positioning system (GPS).

[0041] The radar device 20 is installed on the tripod of the aircraft 100. The radar device 20 is in communication connection with the control system. The radar device 20 transmits the collected observation data to the control system for processing.

[0042] It should be noted that the aircraft 100 may include two or more tripods, and the radar device 20 is mounted on one of the tripods. The radar device 20 may also be mounted at other locations of the aircraft 100, which is not specifically limited.

[0043] The radar device 20 mainly includes a radio frequency front-end module and a signal processing module. The radio frequency front-end module may include a transmitting antenna and a receiving antenna. The transmitting antenna is used to send signals to the target, and the receiving antenna is used to receive signals reflected by the target. The signal processing module is responsible for generating a modulated signal and processing and analyzing the collected intermediate frequency signal. The target is, for example, an obstacle, which may be a building, a tower, a tree, etc.

[0044] The RF front-end module includes a transmitting antenna, a first receiving array and a second receiving array. The arrangement direction between the first receiving array and the second receiving array is designed to be a preset angle, such as the preset angle is 60 degrees, 90 degrees or 120 degrees. The signal processing module is responsible for generating a modulated signal and processing and analyzing the collected intermediate frequency signal.

[0045] The arrangement direction between the first receiving array and the second receiving array is designed to be a preset angle, so that the radar device can measure at least two distance angle images about the surrounding environment of the aircraft, and the distance angle image includes distance information and angle information from the target in the surrounding environment to the radar device. In one embodiment, the distance angle image can be a range Doppler angle map.

[0046] Specifically, the first receiving array includes at least two receiving array elements, and the second receiving array includes at least two receiving array elements. The modulated signal is received to generate a high-frequency signal whose frequency changes linearly with the modulated signal, which is radiated outward through the transmitting antenna. The electromagnetic wave encounters the ground, the target object or the obstacle and is reflected back, and then is received by the first receiving array and the second receiving array, thereby obtaining the observation data collected by the array radar, that is, the radar image.

[0047] For example, Figure 2 As shown, the transmitting antenna is Tx, which is used to transmit radar signals to targets in the surrounding environment of the aircraft. The first receiving array includes receiving array element Rx1 (first antenna) and receiving array element Rx2 (second antenna), and the second receiving array includes receiving array element Rx1 (first antenna) and receiving array element Rx3 (third antenna), which are respectively used to receive radar signals reflected back by targets in the surrounding environment.

[0048] In the embodiment of the present application, the first receiving array and the second receiving array are designed at a 90-degree angle, and of course other angles are also possible. The first receiving array and the second receiving array each include two receiving array elements, and of course more receiving array elements are also possible.

[0049] In some embodiments, the first receiving array and the second receiving array can share receiving array elements. Figure 2 As shown, the receiving array element shared by the first receiving array and the second receiving array is Rx1, that is, the first antenna Rx1.

[0050] The angle information obtained based on the first receiving array and the second receiving array includes the azimuth angle in the horizontal direction and the pitch angle in the vertical direction. Specifically, Figure 3 As shown, the nose direction of the aircraft is the positive direction of the X-axis, the right side direction of the aircraft is the positive direction of the Y-axis, and the bottom of the aircraft is the positive direction of the Z-axis. The installation direction of the first antenna is consistent with the right side direction of the aircraft, and the installation direction of the second antenna is consistent with the head direction of the aircraft. The position of the first antenna is taken as the origin O, the direction from the first antenna to the second antenna is the direction of the Y-axis, the direction from the first antenna to the third antenna is the direction of the X-axis, and the direction directly below the radar array is the direction of the Z-axis. The radar coordinate system can be established.

[0051] Please refer to Figure 4 , Figure 4is a schematic diagram of the position of the target in the radar coordinate system in the embodiment of the present application, such as Figure 4 As shown, the origin of the radar coordinate system is the position of the first antenna Rx1, the direction of the X-axis of the radar coordinate system is the direction from the first antenna Rx1 to the third antenna Rx3, the direction of the Y-axis of the radar coordinate system is the direction from the first antenna Rx1 to the second antenna Rx2, the direction of the Z-axis of the radar coordinate system is directly below the radar array, θ1 is the angle observed by the first receiving array, that is, the angle between the line from the origin O to the target a and the projection of the line on the YOZ plane of the radar coordinate system, θ2 is the angle observed by the second receiving array, that is, the angle between the line from the origin O to the target a and the projection of the line on the XOZ plane of the radar coordinate system, r1 is the distance of the target a observed by the first receiving array, and r2 is the distance of the target a observed by the second receiving array.

[0052] Assume that the position coordinates of target a in the spatial coordinate system are (x, y, z), then

[0053]

[0054] The aircraft 100 includes a drone, which includes a rotor-type drone, such as a quad-rotor drone, a hexacopter drone, an octo-rotor drone, or a fixed-wing drone, or a combination of a rotor-type and a fixed-wing drone, which is not limited here.

[0055] It should be understood that the above naming of the components of the aircraft 100 is only for identification purposes and should not be understood as limiting the embodiments of this specification. The aircraft 100, specifically the controller of the control system of the aircraft 100, is used to execute any of the hovering methods of the aircraft provided in the embodiments of the present application to achieve precise control of the hovering of the aircraft.

[0056] Exemplarily, for example, the controller is used to: obtain a radar image of the aircraft's surroundings measured by the radar device, the radar image including a first distance angle image corresponding to the first receiving array and a second distance angle image corresponding to the second receiving array; determine a changing speed of the aircraft relative to the surroundings based on the first distance angle image and the second distance angle image; and perform flight control of the aircraft based on the changing speed to achieve hovering.

[0057] For ease of understanding, the following will be combined Figure 1 The aircraft provided in the present application provides a hovering control method, which is introduced in detail.

[0058] See also Figure 5 , Figure 5This is a schematic flow chart of the steps of a hovering method for an aircraft provided in an embodiment of the present application. The hovering control method can be applied to the control system of the aircraft. By executing the hovering control method, precise control of the hovering of the aircraft can be achieved to improve the safety of the aircraft flight.

[0059] like Figure 5 As shown, the hovering control method includes steps S101 to S103.

[0060] S101, obtaining a radar image of the surrounding environment of an aircraft measured by a radar device, where the radar image includes a first range angle image corresponding to a first receiving array and a second range angle image corresponding to a second receiving array;

[0061] S102, determining a change speed of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image;

[0062] S103: Perform flight control on the aircraft based on the changing speed to achieve hovering.

[0063] Among them, the radar device includes a first receiving array and a second receiving array, which are respectively used to receive radar signals reflected by the target. The first receiving array and the second receiving array are arranged at a preset angle, for example, the preset angle includes 60 degrees, 90 degrees or 120 degrees, and of course it can also be other values.

[0064] In some embodiments, the first receiving array includes at least two receiving array elements, or the second receiving array includes at least two receiving array elements, or both the first receiving array and the second receiving array include at least two receiving array elements.

[0065] In some embodiments, the first receiving array and the second receiving array have the same number of array elements. In addition, the first receiving array and the second receiving array can also share receiving array elements.

[0066] The arrangement direction between the first receiving array and the second receiving array is designed to be a preset angle, so that the radar device can measure the same target to obtain at least two distance angle images, and the distance angle image includes distance information and angle information from the target to the radar device.

[0067] Thus, a radar image of the surrounding environment of the aircraft measured by the radar device can be obtained, wherein the radar image includes a first distance angle image corresponding to the first receiving array and a second distance angle image corresponding to the second receiving array. And according to the first distance angle image and the second distance angle image, the change speed of the aircraft relative to the surrounding environment is determined.

[0068] Specifically, the surrounding environment can be identified based on the first distance angle image and / or the second distance angle image, a plurality of target points in the surrounding environment can be determined, and the change rate of the radar signals corresponding to the plurality of target points can be determined; then based on a preset speed determination model, the change speed of the aircraft relative to the surrounding environment can be determined according to the change rate of the radar signals corresponding to the plurality of target points.

[0069] The surrounding environment is identified according to the first distance angle image and / or the second distance angle image, and multiple target points in the surrounding environment are determined. Specifically, feature point detection can be performed on the first distance angle image and / or the second distance angle image based on a preset detection algorithm to obtain multiple target points in the surrounding environment. The preset detection algorithm includes at least one of an extreme value detection algorithm and a CFAR detection algorithm. Of course, other algorithms can also be used, which is not limited here.

[0070] The change rate includes the energy change rate with distance, the energy change rate with angle and the energy change rate with time in radar coordinates, as well as the unit length change rate and unit angle change rate in space coordinates.

[0071] Determine the unit length change rate and the unit angle change rate corresponding to the multiple target points. Specifically, based on the conversion relationship from radar coordinates to spatial coordinates, perform coordinate conversion on the distance angle data of the multiple target points in the first distance angle image and the second distance angle image to obtain position data of the spatial coordinates; and calculate the partial derivative of the position data to obtain the unit length change rate and the unit angle change rate corresponding to the multiple target points.

[0072] For example, the conversion relationship from radar coordinates to space coordinates can be specifically expressed as: A =f A (x,y,z),θ A =g A (x,y,z)r B =f B (x,y,z),θ B =g B (x, y, z), and by taking partial derivatives of the position data, we can get the unit length change rate and unit angle change rate corresponding to multiple target points.

[0073] The speed determination model is obtained by Taylor expansion of the energy expression under the condition that the signal energies of two frames of radar images within a preset time are equal.

[0074] Specifically, by the short time δ t Within a few microseconds (for example), the signal energy of the two radar image frames is almost equal, so we can get:

[0075] P(r,θ,t)=P(r+δ r ,θ+δ θ ,t+δ t ) (1)

[0076] In expression (1), P(r,θ,t) represents the signal energy of a radar image frame, P(r+δ r ,θ+δ θ ,t+δ t ) is expressed as the signal energy of another radar image frame, and the time interval between the two radar images is δ t , δ t The time is short, such as a few microseconds.

[0077] For P(r+δ r ,θ+δ θ ,t+δ t ) is expanded by Taylor, and the following formula can be obtained:

[0078]

[0079] In expression (2), HOT represents a high-order infinitesimal quantity, which can be ignored when the motion is small. According to expressions (1) and (2), we can get:

[0080]

[0081] Since the conversion relationship between radar coordinates and space coordinates is r = f(x, y, z), θ = g(x, y, z), r and θ represent the distance information and angle information from the target to the radar device in the radar coordinate system, respectively, and (x, y, z) represents the position information in the space coordinates. According to the conversion relationship between radar coordinates and space coordinates, the partial derivative of expression (3) can be obtained:

[0082]

[0083] According to expression (4), the first receiving array and the second receiving array specifically correspond to the following expressions:

[0084]

[0085]

[0086] Wherein, in expressions (5) and (6), A represents the first receiving array, B represents the second receiving array, are the energy change rate with distance, energy change rate with angle and energy change rate with time corresponding to the first receiving array and the second receiving array, which can be obtained through the radar image under the radar coordinates. are the unit length change rate and unit angle change rate of the first receiving array and the second receiving array in the space coordinates, respectively, which can be obtained by converting the range angle image under the radar coordinates to the space coordinates and then taking the partial derivative.

[0087] because and Expression (5) and expression (6) can be converted into the following expressions (7) and (8), respectively:

[0088]

[0089]

[0090] Since expressions (7) and (8) involve three unknowns (V x 、V y 、V z ), there are only two equations, so it is impossible to solve for V x 、V y and V z .

[0091] make Expressions (7) and (8) can be converted into the form of matrix equations, specifically:

[0092]

[0093] Wherein, the expression (9) is a preset speed determination model. Based on the preset speed determination model, the speed of change of the aircraft relative to the surrounding environment can be determined according to the change rate of the radar signals corresponding to the multiple target points.

[0094] Specifically, a parameter matrix of the speed determination model can be constructed according to the change rates of the radar signals corresponding to the multiple target points; and based on the constructed parameter matrix, the change speed of the aircraft relative to the surrounding environment is calculated using the least squares method.

[0095] Exemplarily, k target points can be extracted from the measured first distance angle image and / or the second distance angle image, and the change rates of the radar signals corresponding to the k target points are respectively the energy change rate with distance, the energy change rate with angle, and the energy change rate with time, as well as the change rate per unit length and the change rate per unit angle. Construct a parameter matrix. The constructed parameter matrix is ​​specifically:

[0096]

[0097] Therefore, expression (9) can be specifically expressed as:

[0098]

[0099] The above expression can be recorded as AV = b, and V = (A T A) -1 A T b, A T is the transposed matrix of A, (A T A) -1 A T The inverse matrix of A. Among them, the speed of change relative to the surrounding environment obtained includes the horizontal axis speed V in the spatial coordinate system x , vertical axis speed V y and vertical axis velocity V z .

[0100] After determining the speed of change of the aircraft relative to the surrounding environment, the aircraft is controlled to fly at the speed of change to achieve hovering. Since the hovering method determines the speed required for hovering through a radar device, it is not affected by the environment, such as signal quality and light intensity, thereby improving the control accuracy during hovering, thereby improving flight safety and customer experience.

[0101] See also Figure 6 , Figure 6 1 is a schematic flow chart of a hovering method for an aircraft provided in an embodiment of the present application. The hovering method is applied to a control system of the aircraft, specifically a controller of the control system, to achieve precise control of the hovering of the aircraft.

[0102] The aircraft includes a photographing device, such as a gimbal camera, for photographing images of the environment surrounding the aircraft.

[0103] like Figure 6 As shown, the hovering method of the aircraft includes step S201 and step S202.

[0104] S201, determining the environment type of the aircraft's surroundings and a hovering strategy corresponding to the environment type according to the image captured by the shooting device;

[0105] S202: Control the aircraft to hover according to the determined hovering strategy.

[0106] Among them, different hovering strategies correspond to different environment types, and different hovering strategies correspond to different hovering methods; the hovering strategies include hovering control strategies based on radar devices, hovering control strategies based on GPS, or hovering control strategies based on optical flow technology.

[0107] For example, the environment type may include an environment that affects the signal quality of the GPS, such as a flying environment including mountains. In the presence of these obstacles, the GPS signal is generally not good. Therefore, the hovering strategy corresponding to the environment type including obstacles is the hovering control strategy of the radar device. The hovering control strategy based on the radar device is specifically, for example, Figure 5 The hovering method of the aircraft is shown.

[0108] Exemplarily, the environment type may be an indoor environment. In an indoor environment, the GPS signal is generally not good. Therefore, the hovering strategy corresponding to the indoor environment may be a hovering control strategy of the radar device.

[0109] Exemplarily, the environment type may be an outdoor environment. Generally, GPS signals are better in outdoor environments. Therefore, the hovering strategy corresponding to the outdoor environment may be a hovering control strategy based on GPS.

[0110] Exemplarily, the environment type may be a first brightness environment and a second brightness environment, wherein the brightness of the first brightness environment is greater than the brightness of the second brightness environment, the first brightness environment is suitable for using a hovering control strategy based on optical flow technology, and the second brightness environment is not suitable for using a hovering control strategy based on optical flow technology. The first brightness environment and the second brightness environment may be determined using a preset brightness threshold, for example, if the brightness of the environment is greater than the preset brightness threshold, then the current environment of the aircraft is determined to be the first brightness environment, and if the brightness of the environment is not greater than the preset brightness threshold, then the current environment of the aircraft is determined to be the second brightness environment.

[0111] Specifically, the environment type of the aircraft's surroundings can be determined based on the image captured by the shooting device. The captured image can be specifically identified to determine the environment type. For example, if the image is identified to include a mountain, the environment type is determined to be an environment type that includes obstacles. For another example, if the brightness of the image is greater than a preset brightness threshold, the environment type corresponding to the environment is determined to be a first brightness environment.

[0112] Specifically, the hovering strategy corresponding to the environment type can be determined according to a preset correspondence between the environment type and the hovering strategy, for example, the obstacle environment type corresponds to the hovering control strategy based on the radar device, for example, the indoor environment corresponds to the hovering control strategy based on the radar device, and for example, the first brightness environment corresponds to the hovering control strategy based on the optical flow technology.

[0113] The hovering method of the aircraft provided in the above embodiment can switch different hovering control strategies in combination with the surrounding environment of the aircraft. For example, a GPS-based hovering control strategy can be adopted in an open environment (without obstacles). Another example is that in an indoor environment with poor GPS signal, a radar device-based hovering control strategy can be adopted. This further improves the hovering control accuracy of the aircraft and further improves the user experience.

[0114] See also Figure 7 As shown, Figure 7 is a schematic block diagram of an aircraft provided in an embodiment of the present application. Figure 7 As shown, the aircraft 100 further includes at least one or more processors 101 and a memory 102 .

[0115] The processor 101 may be, for example, a micro-controller unit (MCU), a central processing unit (CPU), or a digital signal processor (DSP).

[0116] The memory 102 may be a Flash chip, a read-only memory (ROM) disk, an optical disk, a USB flash drive, or a mobile hard disk.

[0117] Among them, the memory 102 is used to store computer programs; the processor 101 is used to execute the computer program and when executing the computer program, execute any one of the hovering methods of the aircraft provided in the embodiments of the present application to provide control accuracy for the hovering of the aircraft.

[0118] Exemplarily, the processor is used to execute the computer program and implement the following steps when executing the computer program:

[0119] Acquire a radar image of the surrounding environment of the aircraft measured by the radar device, the radar image including a first distance angle image corresponding to the first receiving array and a second distance angle image corresponding to the second receiving array; determine a change speed of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image; and perform flight control on the aircraft based on the change speed to achieve hovering.

[0120] In some embodiments, the preset angle includes 60 degrees, 90 degrees or 120 degrees.

[0121] In some embodiments, the first receiving array includes at least two receiving array elements, and / or the second receiving array includes at least two receiving array elements.

[0122] In some embodiments, the first receiving array and the second receiving array can share receiving array elements.

[0123] In some embodiments, determining the speed of change of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image includes:

[0124] The surrounding environment is identified according to the first distance angle image and / or the second distance angle image, a plurality of target points in the surrounding environment are determined, and the change rate of the radar signals corresponding to the plurality of target points is determined; based on a preset speed determination model, the change speed of the aircraft relative to the surrounding environment is determined according to the change rate of the radar signals corresponding to the plurality of target points.

[0125] In some embodiments, the change rate includes the energy change rate with distance, the energy change rate with angle and the energy change rate with time in radar coordinates, and the unit length change rate and unit angle change rate in space coordinates.

[0126] In some embodiments, determining the unit length change rate and the unit angle change rate corresponding to the plurality of target points includes:

[0127] Based on the conversion relationship from radar coordinates to spatial coordinates, the distance angle data of the multiple target points in the first distance angle image and the second distance angle image are converted to obtain the position data of the spatial coordinates; and the partial derivative of the position data is calculated to obtain the unit length change rate and unit angle change rate corresponding to the multiple target points.

[0128] In some embodiments, the determining the change speed of the aircraft relative to the surrounding environment based on the preset speed determination model and according to the change rate of the radar signals corresponding to the multiple target points includes:

[0129] According to the change rates of the radar signals corresponding to the multiple target points, a parameter matrix of the speed determination model is constructed; based on the constructed parameter matrix, a change speed of the aircraft relative to the surrounding environment is calculated using a least squares method.

[0130] In some embodiments, the speed determination model is obtained by performing Taylor expansion on the energy expression under the condition that the signal energies of two frames of radar images within a preset time are equal.

[0131] In some embodiments, the identifying the surrounding environment according to the first distance angle image and / or the second distance angle image to determine a plurality of target points in the surrounding environment includes:

[0132] Based on a preset detection algorithm, feature point detection is performed on the first distance angle image and / or the second distance angle image to obtain a plurality of target points in the surrounding environment.

[0133] In some embodiments, the preset detection algorithm includes at least one of an extreme value detection algorithm and a CFAR detection algorithm.

[0134] In some embodiments, the changing speed includes a horizontal axis speed, a longitudinal axis speed, and a vertical axis speed in a spatial coordinate system.

[0135] In some embodiments, the aircraft includes a camera for capturing images of the aircraft's surroundings, and the processor is configured to:

[0136] According to the image captured by the shooting device, the environment type of the aircraft's surroundings and the hovering strategy corresponding to the environment type are determined, different environment types correspond to different hovering strategies, and different hovering strategies correspond to different hovering methods; the aircraft is controlled to hover according to the determined hovering strategy.

[0137] In some embodiments, the hovering strategy includes a hovering control strategy based on a radar device, a hovering control strategy based on GPS, or a hovering control strategy based on optical flow technology.

[0138] A computer-readable storage medium is also provided in an embodiment of the present application, wherein the computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and the processor executes the program instructions to implement the steps of any of the methods for hovering an aircraft provided in the above embodiments.

[0139] The computer-readable storage medium may be an internal storage unit of the aircraft described in any of the above embodiments, such as a memory or a memory of the aircraft. The computer-readable storage medium may also be an external storage device of the aircraft, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the aircraft.

[0140] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A hovering method for an aircraft, characterized in that: Applied to an aircraft, the aircraft is equipped with a radar device, the radar device includes a first receiving array and a second receiving array, the first receiving array and the second receiving array are respectively used to receive radar signals reflected by targets in the surrounding environment of the aircraft, and the arrangement directions of the first receiving array and the second receiving array are set at a preset angle; the hovering method includes: Acquire a radar image of the aircraft surrounding environment measured by the radar device, wherein the radar image includes a first range angle image corresponding to the first receiving array and a second range angle image corresponding to the second receiving array; Determining a changing speed of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image; and The aircraft is controlled based on the changing speed to achieve hovering.

2. The method according to claim 1, characterized in that The preset angle includes 60 degrees, 90 degrees or 120 degrees.

3. The method according to claim 1, characterized in that The first receiving array includes at least two receiving array elements, and / or the second receiving array includes at least two receiving array elements.

4. The method according to claim 1, characterized in that: The first receiving array and the second receiving array can share receiving array elements.

5. The method according to any one of claims 1 to 4, characterized in that: Determining the change speed of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image includes: Identify the surrounding environment according to the first distance angle image and / or the second distance angle image, determine a plurality of target points in the surrounding environment, and determine a rate of change of radar signals corresponding to the plurality of target points; Based on a preset speed determination model, the change speed of the aircraft relative to the surrounding environment is determined according to the change rate of the radar signals corresponding to the multiple target points.

6. The method according to claim 5, characterized in that The change rates include the energy change rate with distance, the energy change rate with angle and the energy change rate with time in radar coordinates, and the unit length change rate and unit angle change rate in space coordinates.

7. The method according to claim 5, characterized in that Determine the unit length change rate and unit angle change rate corresponding to multiple target points, including: Based on the conversion relationship from radar coordinates to spatial coordinates, coordinate conversion is performed on the distance angle data of the multiple target points in the first distance angle image and the second distance angle image to obtain position data of the spatial coordinates; and Partial derivatives are calculated for the position data to obtain unit length change rates and unit angle change rates corresponding to the multiple target points.

8. The method according to claim 5, characterized in that The method of determining the change speed of the aircraft relative to the surrounding environment based on the preset speed determination model and according to the change rates of the radar signals corresponding to the multiple target points includes: Constructing a parameter matrix of the speed determination model according to the change rates of the radar signals corresponding to the multiple target points; Based on the constructed parameter matrix, the changing speed of the aircraft relative to the surrounding environment is calculated using the least squares method.

9. The method according to claim 5, characterized in that The speed determination model is obtained by Taylor expansion of the energy expression under the condition that the signal energies of two frames of radar images within a preset time are equal.

10. The method according to claim 5, characterized in that The identifying the surrounding environment according to the first distance angle image and / or the second distance angle image to determine a plurality of target points in the surrounding environment includes: Based on a preset detection algorithm, feature point detection is performed on the first distance angle image and / or the second distance angle image to obtain a plurality of target points in the surrounding environment.

11. The method according to claim 10, characterized in that The preset detection algorithm includes at least one of an extreme value detection algorithm and a CFAR detection algorithm.

12. The method according to claim 5, characterized in that The changing speed includes a horizontal axis speed, a longitudinal axis speed and a vertical axis speed in a spatial coordinate system.

13. The method according to claim 1, characterized in that The aircraft includes a photographing device for photographing an image of the environment surrounding the aircraft, and the method further includes: Determine, based on the image captured by the camera, the environment type of the aircraft's surroundings and the hovering strategy corresponding to the environment type, where different environment types correspond to different hovering strategies, and different hovering strategies correspond to different hovering modes; The aircraft is controlled to hover according to the determined hovering strategy.

14. The method according to claim 13, characterized in that The hovering strategy includes a hovering control strategy based on a radar device, a hovering control strategy based on GPS, or a hovering control strategy based on optical flow technology.

15. The method according to claim 1, characterized in that The first range angle image and the second range angle image include range Doppler angle maps.

16. The method according to claim 1, characterized in that The first distance angle image includes angle information obtained based on the first receiving array, and the second distance angle image includes angle information obtained based on the second receiving array. The angle information obtained based on the first receiving array and the second receiving array includes the azimuth angle in the horizontal direction and the pitch angle in the vertical direction.

17. An aircraft, characterized in that: The aircraft comprises: frame; A radar device, wherein the radar is installed on the frame and comprises a first receiving array and a second receiving array, wherein the first receiving array and the second receiving array are respectively used to receive radar signals reflected by targets in the surrounding environment of the aircraft, and the arrangement directions of the first receiving array and the second receiving array are arranged at a preset angle; Processor and memory; The memory is used to store a computer program; the processor is used to execute the computer program and implement the following steps when executing the computer program: Acquire a radar image of the aircraft surrounding environment measured by the radar device, wherein the radar image includes a first range angle image corresponding to the first receiving array and a second range angle image corresponding to the second receiving array; Determining a changing speed of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image; and The aircraft is controlled based on the changing speed to achieve hovering.

18. The aircraft according to claim 17, characterized in that The preset angle includes 60 degrees, 90 degrees or 120 degrees.

19. The aircraft according to claim 17, characterized in that: The first receiving array includes at least two receiving array elements, and / or the second receiving array includes at least two receiving array elements.

20. The aircraft according to claim 17, characterized in that The first receiving array and the second receiving array can share receiving array elements.

21. The aircraft according to any one of claims 17 to 20, characterized in that: Determining the change speed of the aircraft relative to the surrounding environment according to the first distance angle image and the second distance angle image includes: Identify the surrounding environment according to the first distance angle image and / or the second distance angle image, determine a plurality of target points in the surrounding environment, and determine a rate of change of radar signals corresponding to the plurality of target points; Based on a preset speed determination model, the change speed of the aircraft relative to the surrounding environment is determined according to the change rate of the radar signals corresponding to the multiple target points.

22. The aircraft according to claim 21, characterized in that The change rates include the energy change rate with distance, the energy change rate with angle and the energy change rate with time in radar coordinates, and the unit length change rate and unit angle change rate in space coordinates.

23. The aircraft according to claim 21, characterized in that Determine the unit length change rate and unit angle change rate corresponding to multiple target points, including: Based on the conversion relationship from radar coordinates to spatial coordinates, coordinate conversion is performed on the distance angle data of the multiple target points in the first distance angle image and the second distance angle image to obtain position data of the spatial coordinates; and Partial derivatives are calculated for the position data to obtain unit length change rates and unit angle change rates corresponding to the multiple target points.

24. The aircraft according to claim 21, characterized in that The method of determining the change speed of the aircraft relative to the surrounding environment based on the preset speed determination model and according to the change rates of the radar signals corresponding to the multiple target points includes: Constructing a parameter matrix of the speed determination model according to the change rates of the radar signals corresponding to the multiple target points; Based on the constructed parameter matrix, the changing speed of the aircraft relative to the surrounding environment is calculated using the least squares method.

25. The aircraft according to claim 21, characterized in that The speed determination model is obtained by Taylor expansion of the energy expression under the condition that the signal energies of two frames of radar images within a preset time are equal.

26. The aircraft according to claim 21, characterized in that The identifying the surrounding environment according to the first distance angle image and / or the second distance angle image to determine a plurality of target points in the surrounding environment includes: Based on a preset detection algorithm, feature point detection is performed on the first distance angle image and / or the second distance angle image to obtain a plurality of target points in the surrounding environment.

27. The aircraft according to claim 26, characterized in that The preset detection algorithm includes at least one of an extreme value detection algorithm and a CFAR detection algorithm.

28. The aircraft according to claim 21, characterized in that The changing speed includes a horizontal axis speed, a longitudinal axis speed and a vertical axis speed in a spatial coordinate system.

29. The aircraft according to claim 17, characterized in that: The aircraft includes a photographing device for photographing an image of the aircraft's surroundings, and the processor is used to: Determine, based on the image captured by the camera, the environment type of the aircraft's surroundings and the hovering strategy corresponding to the environment type, where different environment types correspond to different hovering strategies, and different hovering strategies correspond to different hovering modes; The aircraft is controlled to hover according to the determined hovering strategy.

30. The aircraft according to claim 29, characterized in that The hovering strategy includes a hovering control strategy based on a radar device, a hovering control strategy based on GPS, or a hovering control strategy based on optical flow technology.

31. The aircraft according to claim 17, characterized in that: The first range angle image and the second range angle image include range Doppler angle maps.

32. The aircraft according to claim 17, characterized in that The first distance angle image includes angle information obtained based on the first receiving array, and the second distance angle image includes angle information obtained based on the second receiving array. The angle information obtained based on the first receiving array and the second receiving array includes the azimuth angle in the horizontal direction and the pitch angle in the vertical direction.

33. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor implements the steps of the hovering method according to any one of claims 1 to 16.

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