CN117916631A

CN117916631A - Obstacle detection method and device, movable platform and program product

Info

Publication number: CN117916631A
Application number: CN202280059387.0A
Authority: CN
Inventors: 王石荣; 王俊喜; 王春明
Original assignee: SZ DJI Technology Co Ltd
Current assignee: SZ DJI Technology Co Ltd
Priority date: 2022-02-21
Filing date: 2022-02-21
Publication date: 2024-04-19
Also published as: WO2023155195A1

Abstract

An obstacle detection method, an apparatus, a movable platform, a program product, and a computer readable storage medium, applied to a movable platform on which a radar is mounted, wherein the method includes: acquiring a movement direction of the movable platform (310); based on the moving direction, a horizontal detection direction of the radar is controlled so that the radar detects an obstacle in the moving direction (320). In this way, since the radar keeps continuously detecting in the moving direction, it is also possible to continuously detect an obstacle with weak signal energy to increase the energy of the signal reflected by the obstacle, thereby improving the detection probability of such an obstacle and improving the performance of the movable platform in detecting the obstacle.

Description

Obstacle detection method and device, movable platform and program product

Technical Field

The present application relates to the field of mobile platforms, and in particular, to a method and apparatus for detecting an obstacle, a mobile platform, and a program product.

Background

Mobile platforms such as drones, unmanned aerial vehicles, robots, etc. have found widespread use in a number of fields. In order to control the movable platform to safely move in space, various sensors for obstacle avoidance, such as a binocular vision system, a radar, and the like, are often mounted on the movable platform. Radar signals reflected by obstacles with smaller sizes such as wires and branches in space tend to be weaker in energy, and if the radar cannot timely sense the obstacles with weaker signal energy, the operation safety of the movable platform is affected.

Disclosure of Invention

Accordingly, an object of the present application is to provide a method, apparatus, mobile platform and program product for detecting an obstacle, so as to improve the performance of the mobile platform in detecting the obstacle.

In order to achieve the technical effects, the embodiment of the invention discloses the following technical scheme:

In a first aspect, there is provided a detection method of an obstacle applied to a movable platform carrying a radar whose detection direction is changeable with respect to the movable platform, the method comprising:

acquiring the moving direction of the movable platform;

Based on the moving direction, a horizontal detection direction of the radar is controlled so that the radar detects an obstacle in the moving direction.

In a second aspect, there is provided a detection device for an obstacle mounted on a movable platform, the movable platform being mounted with a radar whose detection direction is changeable with respect to the movable platform, the device comprising:

A processor;

A memory for storing processor-executable instructions;

Wherein the processor, when invoking the executable instructions, performs the operations of the method of the first aspect.

In a third aspect, there is provided a movable platform comprising:

A body;

A power assembly for driving the movable platform to move in space;

A radar whose detection direction is changeable with respect to the movable platform;

A processor;

A memory for storing processor-executable instructions;

In a fourth aspect, there is provided a computer program product comprising a computer program which, when executed by a processor, implements the steps of the method of the first aspect.

In a fifth aspect, there is provided a computer readable storage medium having stored thereon computer instructions which, when executed, perform the method of the first aspect.

The method, the device, the movable platform and the program product for detecting the obstacle are applied to the movable platform carrying the radar, and the horizontal detection direction of the radar is controlled based on the movement direction of the movable platform, so that the radar can detect the obstacle in the movement direction. In this way, since the radar keeps continuously detecting in the moving direction, it is also possible to continuously detect an obstacle with weak signal energy to increase the energy of the signal reflected by the obstacle, thereby improving the detection probability of such an obstacle and improving the performance of the movable platform in detecting the obstacle.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.

Fig. 1 is an architecture diagram of an unmanned air vehicle system according to an embodiment of the present application.

Fig. 2 is a schematic diagram illustrating coverage angle ranges of radar transmit beams according to an embodiment of the present application.

Fig. 3 is a flowchart illustrating a method for detecting an obstacle according to an embodiment of the present application.

Fig. 4 is a schematic structural view of a rotary radar according to an embodiment of the present application.

Fig. 5 is a schematic diagram illustrating a horizontal detection range of a movable platform according to an embodiment of the present application.

Fig. 6 (a) - (b) are schematic diagrams illustrating radar tracking of an obstacle according to an embodiment of the present application.

Fig. 7 is a flowchart illustrating a method of detecting an obstacle according to another embodiment of the present application.

Fig. 8 is a schematic structural view of an obstacle detecting apparatus according to an embodiment of the present application.

Fig. 9 is a schematic structural view of a movable platform according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Mobile platforms such as drones, unmanned aerial vehicles, robots, etc. have found widespread use in a number of fields. To control the movable platform to safely move in space, various sensors for obstacle avoidance, such as a binocular vision system, radar, infrared sensor, or TOF (Time of flight) sensor, etc., are often mounted on the movable platform. In practical application, based on different products, use scenes, requirements and the like, different movable platforms are loaded with different types of sensors.

A mobile platform may refer to any device capable of moving, and may include, for example, but not limited to, land vehicles, water vehicles, air vehicles, and other types of motorized vehicles. As an example, the mobile platform may include a passenger vehicle and/or an Unmanned vehicle (un-managed AERIAL VEHICLE, UAV) or the like, and the movement of the mobile platform may include flying.

Taking an unmanned aerial vehicle as an example, fig. 1 is a schematic architecture diagram of an unmanned aerial vehicle system, and this embodiment illustrates a rotary-wing unmanned aerial vehicle (rotorcraft) as an example, and the unmanned aerial vehicle system 100 may include an unmanned aerial vehicle 110, a display device 130, and a remote control device 140. The drone 110 may include, among other things, a power system 150, a flight control system 160, a gantry, and a cradle head 120 carried on the gantry. Drone 110 may communicate wirelessly with remote control device 140 and display device 130.

The frame may include a fuselage and a foot rest (also referred to as landing gear). The fuselage may include a center frame and one or more arms coupled to the center frame, the one or more arms extending radially from the center frame. The foot rest is connected to the fuselage for supporting the unmanned aerial vehicle 110 when landing.

The power system 150 may include one or more electronic speed governors (simply called electric governors) 151, one or more propellers 153, and one or more power motors 152 corresponding to the one or more propellers 153, wherein the power motors 152 are connected between the electronic speed governors 151 and the propellers 153, and the power motors 152 and the propellers 153 are disposed on a horn of the unmanned aerial vehicle 110; the electronic governor 151 is configured to receive a driving signal generated by the flight control system 160 and provide a driving current to the power motor 152 according to the driving signal, so as to control the rotation speed of the power motor 152. The power motor 152 is used to drive the propeller to rotate, thereby powering the flight of the drone 110, which enables one or more degrees of freedom of movement of the drone 110. In some embodiments, the drone 110 may rotate about one or more axes of rotation. For example, the rotation shaft may include a Roll shaft (Roll), a Yaw shaft (Yaw), and a pitch shaft (pitch). It should be appreciated that the motor 152 may be a DC motor or an AC motor. The motor 152 may be a brushless motor or a brushed motor.

Flight control system 160 may include a flight controller 161 and a sensing system 162. One of the functions of the sensing system 162 is to measure pose information of the unmanned aerial vehicle, that is, position information and state information of the unmanned aerial vehicle 110 in space, for example, three-dimensional position, three-dimensional angle, three-dimensional speed, three-dimensional acceleration, three-dimensional angular speed, and the like. The sensor system may also have other roles, such as being useful for collecting environmental observations of the environment surrounding the drone. The sensing system 162 may include, for example, one or more of the following: gyroscopes, ultrasonic sensors, electronic compasses, inertial measurement units (Inertial Measurement Unit, IMU), vision sensors, infrared sensors, TOF (time of flight) sensors, lidar, millimeter wave radar, thermal imaging cameras, global navigation satellite systems, barometers, etc. For example, the global navigation satellite system may be a global positioning system (Global Positioning System, GPS). The flight controller 161 is configured to control the flight of the unmanned aerial vehicle 110, and may control the flight of the unmanned aerial vehicle 110 based on attitude information measured by the sensing system 162, for example. It should be appreciated that the flight controller 161 may control the drone 110 in accordance with preprogrammed instructions or may control the drone 110 in response to one or more remote control signals from the remote control device 140.

Cradle head 120 may include a motor 122. The cradle head may be used to carry a load, such as camera 123. Flight controller 161 can control movement of pan-tilt 120 via motor 122. Alternatively, as another embodiment, the pan-tilt head 120 may further include a controller for controlling the movement of the pan-tilt head 120 by controlling the motor 122. It should be appreciated that the pan-tilt 120 may be independent of the drone 110 or may be part of the drone 110. It should be appreciated that the motor 122 may be a DC motor or an AC motor. The motor 122 may be a brushless motor or a brushed motor. It should also be appreciated that the pan-tilt may be located at the top of the drone or at the bottom of the drone.

The photographing device 123 may be, for example, a device for capturing an image, such as a camera or a video camera, and the photographing device 123 may communicate with and photograph under the control of the flight controller. The photographing device 123 of the present embodiment at least includes a photosensitive element, which is, for example, a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor) sensor or a charge-coupled device (CCD) sensor. It is understood that the camera 123 may be directly fixed to the unmanned aerial vehicle 110, so that the pan-tilt 120 may be omitted.

The display device 130 is located at the ground side of the unmanned aerial vehicle 100, can communicate with the unmanned aerial vehicle 110 in a wireless manner, and can be used to display attitude information of the unmanned aerial vehicle 110. In addition, an image captured by the capturing device 123 may also be displayed on the display apparatus 130. It should be appreciated that display device 130 may be a stand-alone device or may be integrated into remote control device 140.

The remote control device 140 is located at the ground side of the unmanned aerial vehicle system 100, and can communicate with the unmanned aerial vehicle 110 in a wireless manner, so as to remotely operate the unmanned aerial vehicle 110.

It should be understood that the above designations of the components of the unmanned air vehicle are for identification purposes only and should not be construed as limiting embodiments of the present application.

In some scenes, such as a movable platform of a consumer unmanned plane, a radar can be carried to realize an obstacle avoidance function. The radar is composed of a transmitter, a receiver, an information processing system and the like, and can transmit detection signals (beams) and receive signals reflected from obstacles, and acquire the spatial positions of the obstacles according to the reflected signals, including information such as distance, angle, speed, energy and the like. The radar may include, but is not limited to, phased array radar, rotary radar, microwave radar, millimeter wave radar, and the like. In certain scenarios, microwave radar has a longer detection distance than other sensors and can detect smaller obstacles, such as 0.5mm wires.

In order to realize omnidirectional obstacle avoidance, a radar with a detection direction which can be changed relative to the movable platform is often mounted on the movable platform. The detection direction may include a horizontal detection direction and a vertical detection direction. The horizontal detection direction may refer to a detection direction parallel to a horizontal plane of a movable platform coordinate system (body system); the vertical detection direction may refer to a detection direction perpendicular to a horizontal plane of the movable platform coordinate system. The detection direction of the radar is changeable with respect to the movable platform, it may be that the horizontal detection direction of the radar is changeable with respect to the movable platform, and/or the vertical detection direction of the radar is changeable with respect to the movable platform. As shown in fig. 2, a frame of radar transmit beam may cover a range of angles, including a horizontal range of angles covered in the horizontal detection direction and a vertical range of angles covered in the vertical detection direction. Wherein the horizontal and vertical angular ranges may be of the same or different size, e.g., the horizontal angular range may be greater than the vertical angular range.

There are various methods for changing the detection direction of the radar, such as the above-mentioned rotating radar, which can change the detection direction of the radar by mechanical rotation; also as with the phased array radar described above, the detection direction of the radar can be changed by controlling the phase of the transmit beam. During operation of the movable platform, the radar can continuously change the detection direction to realize omnidirectional obstacle avoidance (rotation mode). Taking a rotary radar as an example, the rotary radar can achieve 360-degree omni-directional detection through mechanical rotation. In the rotation mode, the rotating radar may rotate several, e.g. 15, revolutions per second, so that in one revolution the radar can only transmit a few frames of beams in each direction. However, for small-sized obstacles in space such as wires, branches, etc., the energy of the reflected signal thereof is weak, and it is difficult for the radar to detect such obstacles by echo signals of a single frame. In some scenes, when the moving speed of the movable platform is high, for example, when the unmanned aerial vehicle flies at a high speed, lei Dare cannot detect the obstacles so that the unmanned aerial vehicle collides with the obstacles, parts of the unmanned aerial vehicle can be damaged, and even crash loss is caused, which is a great hidden danger for safe flight of the unmanned aerial vehicle.

To this end, the present application proposes a method for detecting an obstacle, which is applied to a movable platform, and may be, for example, an unmanned aerial vehicle equipped with an unmanned flying system as shown in fig. 1. The movable platform is mounted with a radar whose detection direction can be changed with respect to the movable platform, and may be, for example, a radar whose detection direction can be changed such as a rotary radar or a phased array radar. The method comprises the steps as shown in fig. 3:

Step 310: acquiring the moving direction of the movable platform;

step 320: based on the moving direction, a horizontal detection direction of the radar is controlled so that the radar detects an obstacle in the moving direction.

As described above, the detection direction of the radar can be divided into a horizontal detection direction and a vertical detection direction. The horizontal detection direction of the radar may be a detection direction parallel to a horizontal plane of a movable platform coordinate system (body system). The control of the horizontal detection direction of the radar may be control of the detection of the radar in the horizontal direction, including keeping the horizontal detection direction of the radar unchanged or changing the horizontal detection direction of the radar. The direction of movement of the movable platform may or may not be consistent with the movable platform head orientation. Taking the unmanned aerial vehicle as an example, when the unmanned aerial vehicle flies forward, the moving direction (flying direction) of the unmanned aerial vehicle can be consistent with the direction of the head of the unmanned aerial vehicle, and when the unmanned aerial vehicle flies on the side of the unmanned aerial vehicle, the moving direction of the unmanned aerial vehicle can be inconsistent with the direction of the head of the unmanned aerial vehicle. During take-off or landing, the moving direction of the unmanned aerial vehicle is inconsistent with the machine head direction.

The beam emitted by the radar may be reflected by an obstacle to form an echo signal. After the radar receives the echo signal, processing of the echo signal and obstacle detection can be performed. Processing of the echo signals may include, but is not limited to, dc blocking, amplitude phase calibration, signal windowing, distance-dimensional fast fourier transform (Fast Fourier transform, FFT), speed-dimensional FFT, angle-dimensional FFT, constant false-alarm detection (constant false-ALARM RATE, CFAR), and peak detection to detect obstructions. The above-described signal processing procedure may refer to the related art, and the present application is not discussed herein.

According to the obstacle detection method provided by the embodiment, the horizontal detection direction of the radar is controlled based on the moving direction of the movable platform, so that the radar can detect the obstacle in the moving direction. The mode of operation in which the control radar is kept in the direction of movement to detect an obstacle may be referred to as a fire control mode of the radar. Compared with the rotation mode, since the radar keeps continuously detecting in the moving direction, the amplitude of the signal reflected by the obstacle can be accumulated in time, so that the signal-to-noise ratio of the reflected signal is improved. Therefore, the detection probability of the obstacle is improved and the performance of the movable platform for detecting the obstacle is improved by continuously detecting the obstacle with weaker signal energy to increase the energy of the signal reflected by the obstacle.

In some scenarios, if a portion of the beam emitted by the radar is reflected by the ground, the echo signal reflected by other obstacles may be masked due to the larger energy of the signal reflected by the ground, thereby causing detection interference. To this end, in some embodiments, the above method may further comprise the steps of: the vertical detection direction of the radar is controlled to control the detection direction of the radar to be parallel to the ground. Wherein the vertical detection direction may be a detection direction perpendicular to a horizontal plane of the movable platform coordinate system.

As an example, if the movable platform is located on a horizontal plane, the radar vertical detection direction is controlled to be parallel to the horizontal plane; if the terrain where the movable platform is located has a certain slope or gradient, the terrain information, such as the information of the slope, gradient and the like of the terrain, can be obtained based on the prior information of the sensors, maps and the like carried by the movable platform, and the vertical detection direction of the radar is controlled to be parallel to the ground based on the terrain information. Among them, the sensors for acquiring the topographic information may include, but are not limited to, image sensors, lidar, etc. Thus, when the detection direction of the radar is parallel to the ground, the wave beam emitted by the radar is not reflected by the ground, and the covering of the obstacle echo signal is avoided.

In other embodiments, the echo signals received by the radar may also be filtered to remove echo signals reflected from the ground. In particular, the terrain information, such as terrain slope, grade, etc., may be obtained based on a sensor onboard the mobile platform, or a priori information such as a map. And filtering the ground reflected echo signals from the received echo signals based on the terrain information, thereby avoiding masking of obstacle echo signals.

In some embodiments, the radar carried by the mobile platform may be a rotary radar. Fig. 4 shows a cross-sectional view of an exemplary rotary radar, the rotary radar 400 including a housing 410, a stationary bracket 420 provided in the housing 410, a motor mounted on the stationary bracket 420, the motor including a stator 430 and a rotor 440, a rotary bracket 450 mounted on the rotor 440, the rotary bracket 450 rotating with the rotor 440 of the motor; mounted on the rotating bracket 450 are an antenna structure 460 and an antenna controller 470, the antenna controller 470 for controlling the antenna structure 460 to transmit and receive radar signals.

Further, in some embodiments, the rotary radar 400 further includes an angle sensor 480, the angle sensor 480 being configured to detect a rotation angle of the rotor 440. The angle sensor 480 may be one or more of a hall sensor, a potentiometer, and an encoder. It is understood that the angle sensor 480 detects the rotation angle of the rotor 440, that is, the rotation angle of the rotary radar 400. The apparatus using the rotary radar 400 can assist in judging the transmitting direction of the radar signal and the direction of the received radar signal according to the rotation angle of the rotary radar 400, and further judging the relative direction of the obstacle and the apparatus using the rotary radar 400.

As an example, the swivel mount 450 may be perpendicular to the horizontal plane of the movable platform coordinate system (body system). In this way, the mechanical rotation of the rotary radar 400 in the horizontal direction can be controlled by controlling the mechanical rotation of the rotary radar about the rotary bracket 450, thereby controlling the horizontal detection direction of the radar.

As an example, the swivel mount 450 may be parallel to the horizontal plane of the movable platform coordinate system and perpendicular to the central axis of the fuselage. In this way, the mechanical rotation of the rotary radar 400 in the vertical direction can be controlled by controlling the mechanical rotation of the rotary radar about the rotary bracket 450, thereby controlling the vertical detection direction of the radar.

In some embodiments, the radar onboard the mobile platform may be a phased array radar. The antenna array surface of the phased array radar comprises a plurality of radiating units and receiving units, the phases of currents fed to the radiating units are controlled by a computer, and the phased array radar can radiate beams with different directivities in space based on the electromagnetic wave coherence principle. Thus, phased array radar can control the horizontal detection direction and/or the vertical detection direction of the radar by controlling the phase of the transmit beam. For specific phase control methods, reference may be made to the related art, and the present application will not be described in detail herein.

In some embodiments, the radar may be mounted on the movable platform via a cradle head. The cradle head can be a two-axis cradle head or a three-axis cradle head. For example, a cradle head 120 as shown in fig. 1. The head may include yaw (yaw) axis motors, pitch (pitch) axis motors, yaw axis arms, and pitch axis arms. The yaw shaft arm is used for supporting the yaw shaft motor, and the pitch shaft arm is used for supporting the pitch shaft motor. As an example, the horizontal detection direction of the radar may be controlled by controlling yaw rotation of the pan-tilt about the yaw axis arm. As an example, the vertical detection direction of the radar can be controlled by controlling the rotation of the pan head about the pitch axis of the pitch axis arm.

In some embodiments, the radar carried by the mobile platform may be a rotary phased array radar, i.e. the radar may either mechanically rotate about a rotating gantry or control the phase of the transmitted beam. In this embodiment, the rotating bracket of the rotating phased array radar may be disposed perpendicular to the horizontal plane of the movable platform coordinate system, and the mechanical rotation of the rotating phased array radar in the horizontal direction is controlled by controlling the mechanical rotation of the rotating phased array radar around the rotating bracket, so as to control the horizontal detection direction of the radar; the vertical detection direction of the rotary phased array radar is controlled by controlling the phase of the transmit beam.

As described above, the radar single frame transmitting beam may cover a certain angle range, and in some embodiments, if the angle range covered by the radar single frame transmitting beam in the horizontal detection direction is not smaller than the horizontal detection range preset in the moving direction of the movable platform, the horizontal detection direction of the radar is controlled based on the moving direction in step 320, and the horizontal detection direction of the radar may be controlled to be consistent with the moving direction. The preset horizontal detection range in the moving direction may be an angle range set for ensuring the moving safety of the movable platform, for example, 30 °. For another example, the horizontal detection range preset in the moving direction may be inversely related to the moving speed of the movable platform. The greater the moving speed of the movable platform, the smaller the horizontal detection range.

In other embodiments, if the angle range covered by the beam emitted by the radar in the single frame in the horizontal detection direction is smaller than the horizontal detection range preset in the moving direction of the movable platform, in step 320, the horizontal detection direction of the radar is controlled based on the moving direction, which may be to control the radar to detect the obstacle in different angle ranges of the horizontal detection range respectively. Because the angle range covered by the beam emitted by the radar in a single frame in the horizontal detection direction is smaller than the preset horizontal detection range, the radar needs to be detected for multiple times in the horizontal detection range, so that the radar can cover the whole horizontal detection range.

As an example, if the preset horizontal detection range is 180 °, and the beam emitted by the radar in a single frame can only cover the range of 30 ° to 40 ° in the horizontal detection direction, the radar can perform several frame detections in different angle ranges to cover the entire horizontal detection range. For example, detection is performed at 15 ° left, 45 ° left, 90 ° left, 15 ° right, 45 ° right, and 90 ° right, respectively, in the moving direction so as to cover the entire horizontal detection range.

In some embodiments, the controlling radar may detect the obstacle in different angle ranges of the horizontal detection range, and may detect the obstacle in different angle ranges according to a preset detection parameter. The detection parameters may include, but are not limited to, one or more of an angular range, a detection time for each angular range, or a detection order between angular ranges.

As an example, as shown in fig. 5, the preset horizontal detection range in the moving direction of the movable platform is 120 °. While the beam emitted by a radar single frame can only cover an angular range of about 30 ° in the horizontal detection direction. The preset horizontal detection range may be divided into 4 angular ranges a-D as shown in fig. 5. The angle ranges covered by the angle ranges a-D may be the same or different, and two adjacent angle ranges may have a coincident angle range or no coincident angle range, so long as all the angle ranges can cover the entire horizontal detection range. Further, the detection time for each angle range may be set, for example, how many seconds of detection each angle range is performed, or how many frames of detection are performed, respectively. The detection times for the different angular ranges may be the same or different. If the detection time of the angle range A and the angle range D is 5ms, the detection time of the angle range B and the angle range C is 10ms. In addition, a detection order between a plurality of angle ranges may be set, and for example, the detection order may be sequentially from the angle range a to the angle range D. Therefore, the radar can perform multi-frame detection in different angle ranges, and the whole preset horizontal detection range can be covered, so that the moving safety of the movable platform is ensured.

In some embodiments, if an obstacle exists in the moving direction, the horizontal detection direction of the radar may be controlled to face the obstacle, so that the direction with the strongest gain of the transmitting beam is directed to the obstacle, thereby increasing the intensity of the reflected signal of the obstacle and improving the detection probability of the obstacle. Alternatively, after a preset time elapses from the direction of horizontal detection of the radar toward the obstacle, the horizontal detection direction of the radar may be controlled to return to the original direction, that is, the direction before the direction toward the obstacle, and the preset time may be 1-3ms. Optionally, the radar may also be controlled to track obstacles in the direction of movement. If it is determined that there are obstacles in the moving direction of the movable platform during the movement of the movable platform, the radar can be controlled to track the detected obstacle with a small number of other obstacles in the moving direction. As shown in fig. 6 (a), taking the unmanned aerial vehicle as an example, the unmanned aerial vehicle detects 3 obstacles in the moving direction based on the radar in the first position. As shown in fig. 6 (b), along with the flight of the unmanned aerial vehicle in the moving direction, the position of the obstacle relative to the unmanned aerial vehicle can be acquired at the second position, and the radar horizontal detection direction is adjusted to face the obstacle, so that the tracking of the obstacle is realized. The radar may keep track of the obstacle until the obstacle is far from the moving direction of the movable platform, for example, the preset horizontal detection range in the moving direction, and the tracking is canceled, so that the horizontal detection direction of the radar is controlled to return to the original direction, i.e. the direction before the obstacle is tracked.

In some embodiments, the obstacle in the moving direction may be detected by radar when detecting the obstacle in the moving direction. In other embodiments, the movable platform is further equipped with sensors for detecting obstacles other than radar, such as the above-mentioned ultrasonic sensor, visual sensor, infrared sensor, TOF sensor, etc. The obstacle in the moving direction may be detected by another sensor. For example, if the other sensor detects that an obstacle exists in a certain direction in the moving direction, the other sensor may send the position information of the obstacle directly or through a processor to the radar so that the horizontal detection direction of the radar is directed toward the obstacle. In other embodiments, the obstacle in the direction of movement may also be determined based on a priori information of the map. The map may be pre-stored on the mobile platform, or obtained by real-time networking based on a communication module carried by the mobile platform. For example, based on the location of the movable platform, environmental information about the location may be obtained from prior information on the map, whether an obstacle, such as a utility pole, a street lamp, or the like, exists around the movable platform may be determined from the environmental information, and relative location information of the obstacle and the movable platform may be obtained, so that the horizontal detection direction of the radar may be controlled toward the obstacle.

In some scenarios, if there are multiple obstacles, the horizontal detection direction of the radar may be controlled to be respectively directed to the obstacles, so that the direction in which the transmit beam gain is strongest is directed to each obstacle one by one. If the angle range covered by the beam emitted by the radar in the single frame in the horizontal detection direction is not smaller than the horizontal detection range preset in the moving direction of the movable platform, the radar can find a plurality of obstacles in the detection of at least one frame, and can control the horizontal detection direction of the radar to face to each detected obstacle. If the angle range covered by the beam emitted by the radar in a single frame in the horizontal detection direction is smaller than the horizontal detection range preset in the moving direction of the movable platform, the radar can detect the obstacle in different angle ranges of the horizontal detection range to cover the whole horizontal detection range, and then the radar can detect all the obstacles in the whole horizontal detection range in multi-frame detection. Therefore, the radar can be controlled to detect the obstacle in different angle ranges according to preset detection parameters until the detection of the whole horizontal detection range is completed, so that the obstacle in the whole horizontal detection range can be found. Then the horizontal detection direction of the radar is controlled to face each obstacle. As in the example shown in fig. 5, the angular range a-D may be first scanned in accordance with the detection order, and after all the obstacles in the entire horizontal detection range are found, the horizontal detection direction of the radar may be controlled to be directed toward each obstacle, respectively. Or when the radar detects different angle ranges according to the detection parameters, if the radar detects the obstacle, the horizontal detection direction of the radar is controlled to face the detected obstacle, namely the detection of the whole horizontal detection range is not required to be completed. As in the example shown in fig. 5, the radar detects the entire horizontal detection range according to the detection sequence from the angle range a to the angle range D, if an obstacle is found in the angle range B, the horizontal detection direction of the radar can be directly controlled to face the obstacle, and after the data acquisition of the obstacle is completed, the detection of the angle range C and the angle range D is completed according to the detection sequence.

In some embodiments, if the radar detects a plurality of obstacles, including detecting a plurality of obstacles in the entire horizontal detection range, or detecting a plurality of obstacles in a certain angle range, the horizontal detection direction of the radar may be controlled to sequentially face the plurality of obstacles or the horizontal detection direction of the radar may be controlled to face only the obstacle with the highest priority based on a preset detection priority order.

As an example, the detection priority order may include a direction priority of the obstacle. Alternatively, the detection priority of the obstacle closer to the moving direction is larger. As in the example above, if an obstacle appears in each of the angular ranges a-D, then the detection priority of the obstacle in the angular range B, C is greater than the detection priority of the obstacle in the angular range A, D. Since the movable platform has a greater probability of collision with the obstacle appearing in the moving direction, the safety of movement can be ensured by preferentially detecting the approaching obstacle in the moving direction.

Optionally, the direction priority of the obstacle may also be consistent with the detection order among the multiple angular ranges, to simplify the computational resources of the detection priority order. If the obstacle appears in the angle ranges a-D as in the above example, the obstacle in each angle range may be detected sequentially according to the detection order of the angle ranges a-D.

As an example, the detection priority order may include a detection signal amplitude priority of the obstacle. For example, an obstacle having a high detection signal amplitude has a higher detection priority than an obstacle having a low detection signal amplitude. Compared with the obstacle with low detection signal amplitude, the radar can complete data acquisition of the obstacle with high detection signal amplitude in a short time. Therefore, the obstacle with high signal amplitude is preferentially detected, and more obstacles can be detected in a short time, so that the detection performance of the movable platform on the obstacle is improved.

As an example, the detection priority order may include a distance priority of the obstacle from the movable platform. For example, an obstacle having a small distance to the movable platform has a higher detection priority than an obstacle having a large distance. And preferentially detecting the obstacle closer to the mobile platform so that the mobile platform can make an obstacle avoidance decision according to the obstacle information to avoid collision between the mobile platform and the obstacle.

As an example, the detection priority order may include a combination of a plurality of direction priorities of the obstacle, detection signal amplitude priorities of the obstacle, and distance priorities of the obstacle and the movable platform. The detection priority of each obstacle may be determined, for example, first according to the distance of the obstacle from the movable platform. For obstacles with the same priority, the detection priority of each obstacle can be further distinguished according to the detection signal amplitude of the obstacle. Various combinations of priorities are possible, and are not limited to the examples listed above. Those skilled in the art can combine according to actual needs, and the present application is not limited herein.

As described above, in the process of the operation of the movable platform, the radar can continuously change the detection direction in the rotation mode to realize omnidirectional obstacle avoidance; the continuous detection of obstacles in the direction of movement can be maintained in the fire control mode. In some embodiments, the radar may be controlled to enter a fire control mode, e.g. switch from a rotation mode to a fire control mode, to maintain continuous detection in the direction of movement, if any of the following conditions is met.

Condition 1: the number of obstacles in other directions than the moving direction is less than a preset number threshold. By way of example, the movable platform moves forward, other directions may include, but are not limited to, left and right sides, above and below the movable platform. If the number of the obstacles in other directions is smaller, the radar can be controlled to enter a fire control mode, and the detection of the obstacles in the moving direction is kept.

Condition 2: the distance between the obstacle and the movable platform in other directions except the moving direction is larger than a preset distance threshold value. If the obstacle exists in other directions, but the distance between the obstacle and the movable platform is large enough to not influence the safe movement of the movable platform, the radar can be controlled to enter a fire control mode, and the obstacle in the moving direction can be detected.

Condition 3: the number of obstacles in the moving direction is greater than a preset number threshold. The preset number threshold may be identical to the number threshold in the condition 1, or may be two thresholds with different sizes. If more obstacles exist in the moving direction, the safety movement of the movable platform can be influenced, the radar can be controlled to enter a fire control mode, and the detection of the obstacles in the moving direction is kept.

Condition 4: the preset relief exists in a preset distance in the moving direction. The preset topography may include, but is not limited to, topography with high relief, including topography of more surface buildings or trees, etc. As an example, the preset topography may be one or more of a woodland, a city, a mountain land, and a farmland. Because the topography is too big or there are more earth surface buildings, trees, etc., the movable platform is easy to collide with the topography big in the moving process or collide with the earth surface buildings, trees, etc., thus the radar can be controlled to enter a fire control mode, and the continuous detection is kept in the moving direction.

Condition 5: the moving speed of the movable platform is greater than a preset speed threshold. The preset speed threshold may be 3m/s. If the moving speed of the movable platform is high, the obstacle which is difficult to detect becomes a serious collision threat of the movable platform, and the probability of damaging the movable platform structure after colliding with the obstacle is high. The movable platform needs to acquire the information of the obstacle in the moving direction more timely so as to make obstacle avoidance planning. Therefore, when the moving speed of the movable platform is high, the radar can be controlled to enter a fire control mode, and the detection of the obstacle in the moving direction is kept.

Condition 6: the movable platform is capable of predicting a movement direction within a preset time period. In fire mode, the radar needs to maintain continuous detection in the direction of movement. If the moving direction of the movable platform is continuously changed, the movable platform may not be able to timely adjust the horizontal detection direction of the radar to the moving direction of the movable platform. Taking unmanned aerial vehicle as an example, when unmanned aerial vehicle is in manual flight mode, its degree of freedom of flight is great, and unmanned aerial vehicle can't prejudge the place that the user will control unmanned aerial vehicle to the next moment, promptly can't prejudge flight trajectory and flight direction, consequently is difficult to control the detection that the radar moment kept in the flight direction. In this way, if the movable platform moves according to the pre-planned track or the movable platform moves towards the set target, the movable platform can predict the moving direction of the next moment according to the pre-planned track or the set target, so that the detection of the radar moment in the moving direction can be controlled.

Before entering the fire control mode, the information of the obstacles in the moving direction and other directions except the moving direction includes quantity information, distance information and landform information within a preset distance in the moving direction, which can be obtained based on radar detection as an example. For example, the radar performs omnidirectional detection in a rotation mode, and can detect obstacle information and landform information in all directions. And judging whether the radar enters a fire control mode or not based on the obstacle information acquired in the rotation mode. Further, a sensor for detecting an obstacle other than radar, such as the above-described ultrasonic sensor, visual sensor, infrared sensor, TOF sensor, or the like, may be mounted on the movable platform. As an example, the information may be acquired based on other sensor detections. For example, other sensors may detect obstacle information in different directions, and the mobile platform may determine whether the radar enters a fire control mode based on the acquired obstacle information. As an example, the above information may also be determined based on a priori information of the map. The map may be pre-stored on the mobile platform, or obtained by real-time networking based on a communication module carried by the mobile platform. For example, based on the location of the movable platform, environmental information about the location may be obtained from prior information of the map, whether an obstacle, such as a utility pole, a street lamp, etc., exists around the movable platform may be determined from the environmental information, and the obtained obstacle information may be used to determine whether the radar enters the fire control mode based on the obstacle information obtained from the map.

In some embodiments, the radar may be controlled to enter a rotation mode, e.g., switch from a fire mode to a rotation mode, to achieve omnidirectional obstacle avoidance, if any of the following conditions are met.

Condition 7: the number of obstacles in other directions than the moving direction is more than a preset number threshold. If more barriers exist in other directions, the safe movement of the movable platform can be influenced, and the radar can be controlled to enter a rotation mode to obtain a larger detection range, so that the barriers and the movable platform are prevented from colliding.

Condition 8: the distance between the obstacle and the movable platform in other directions except the moving direction is smaller than a preset distance threshold value. If the obstacle in other directions is closer to the movable platform, collision between the movable platform and the obstacle is easily caused, so that the radar can be controlled to enter a rotation mode, and the obstacle is detected in the moving direction and other directions, so that omnidirectional obstacle avoidance is realized.

Condition 9: the moving speed of the movable platform is smaller than a preset speed threshold. When the moving speed of the movable platform is smaller, a larger detection range can be obtained to ensure the omnidirectional safety of the movable platform, so that the radar can be controlled to enter a rotating mode, and obstacles are detected in the moving direction and other directions to realize omnidirectional obstacle avoidance.

Condition 10: the movable platform is in a manual control mode. As described above, when the movable platform is in the manual control mode, the movable platform cannot predict the movement position and movement direction at the next moment due to the large movement freedom, so that the radar can be controlled to enter the rotation mode, and the obstacle is detected in the movement direction and other directions, so as to realize omnidirectional obstacle avoidance.

Before entering the rotation mode, the obstacle information in other directions includes the number information and the distance information, and the information can be acquired based on other sensors mounted on the movable platform for detecting the obstacle. The movable platform can judge whether the radar enters a rotation mode or not based on obstacle information in other directions acquired by other sensors. As an example, the above information may also be determined based on a priori information of the map. The movable platform may determine whether the radar enters a rotation mode based on obstacle information in other directions acquired from the map.

In some embodiments, when the radar detects an obstacle in the moving direction and acquires sufficient information for the obstacle, the movable platform may plan a moving track of the movable platform based on the obstacle information acquired by the radar. As an example, the inertial measurement unit (Inertial Measurement Unit, IMU) mounted on the movable platform may be used to obtain motion information of the movable platform and to plan or update the movement track in combination with the obstacle information.

The method for detecting the obstacle is applied to a movable platform carrying the radar, and the radar can detect the obstacle at least in a rotation mode or a fire control mode. In order to improve the detection probability of the minute obstacle, the radar may be controlled to switch from the rotation mode to the fire control mode under certain conditions, and the horizontal detection direction of the radar is controlled based on the movement direction of the movable platform so that the radar keeps detecting the obstacle in the movement direction. Since the radar remains continuously detecting in the direction of movement, the signal gain reflected by the obstacle can be accumulated over time. Compared with a radar single-frame acquisition signal in a rotation mode, the signal to noise ratio of an echo signal can be improved in a fire control mode in a multiple mode, and the gain of a reflection signal is improved. Therefore, the detection probability of the obstacle is improved and the performance of the movable platform for detecting the obstacle is improved by continuously detecting the obstacle with weaker signal energy to increase the energy of the signal reflected by the obstacle.

In addition, the application also provides a detection method of the obstacle, which is applied to the movable platform carrying the rotary microwave radar, wherein the rotary support of the rotary microwave radar can be arranged perpendicular to the horizontal plane of the coordinate system of the movable platform, and the mechanical rotation of the radar in the horizontal direction can be controlled by controlling the mechanical rotation of the radar around the rotary support. The vertical detection direction of the radar can also be controlled by controlling the phase of the transmitted beam of the radar. The radar may detect obstacles in at least a rotational mode or a fire control mode. The method may include the steps as shown in fig. 7:

step 710: the radar enters a rotation mode to omnidirectionally detect obstacles;

as an example, the radar may be controlled to enter a rotation mode to detect the surrounding environment when the movable platform is powered on or when the operation is started.

Step 720: acquiring the moving direction of the movable platform;

Step 731: whether the number of obstacles in other directions than the moving direction is less than a preset number threshold;

If yes, go to step 741; if not, go to step 732.

Step 732: whether the distance between the obstacle and the movable platform in other directions except the moving direction is larger than a preset distance threshold value or not;

If yes, go to step 741; if not, go to step 733.

Step 733: whether the number of obstacles in the moving direction is greater than a preset number threshold;

If yes, go to step 741; if not, step 734 is performed.

Step 734: whether a preset landform exists within a preset distance in the moving direction or not;

if yes, go to step 741; if not, step 735 is performed.

Step 735: whether the moving speed of the movable platform is greater than a preset speed threshold;

if yes, go to step 741; if not, go to step 736.

Step 736: whether the movable platform can predict the moving direction within a preset time period;

If yes, go to step 741; if not, step 710 is performed, i.e., the radar is kept in rotation mode to detect an obstacle omnidirectionally.

Step 741: the radar enters a fire control mode, and the mechanical rotation of the radar in the horizontal direction is controlled to enable the radar to detect an obstacle in the moving direction;

step 742: controlling the phase of a radar transmitting beam to control the detection direction of the radar to be parallel to the ground;

Step 743: if an obstacle exists in the moving direction, controlling the horizontal detection direction of the radar to face the obstacle;

Step 744: processing echo signals reflected by the obstacle to acquire obstacle information;

step 745: and planning a moving track of the movable platform based on the obstacle information.

In addition, steps 751-754 may be performed simultaneously with steps 741-745:

Step 751: whether the number of obstacles in other directions than the moving direction is more than a preset number threshold;

if yes, go to step 710 to switch from fire control mode to rotation mode; if not, go to step 752.

Step 752: whether the distance between the obstacle and the movable platform in other directions except the moving direction is smaller than a preset distance threshold value;

If yes, go to step 710 to switch from fire control mode to rotation mode; if not, step 753 is performed.

Step 753: whether the moving speed of the movable platform is smaller than a preset speed threshold value or not;

If yes, go to step 710 to switch from fire control mode to rotation mode; if not, then step 754 is performed.

Step 754: whether the movable platform is in manual control mode.

If yes, go to step 710 to switch from fire control mode to rotation mode; if not, step 751 is returned to, i.e., steps 751-754 are repeated, and the radar remains operating in fire control mode.

Based on the method for detecting an obstacle according to any of the foregoing embodiments, the present application further provides a schematic structural diagram of an obstacle detecting device shown in fig. 8. At the hardware level, as shown in fig. 8, the detection device of the obstacle includes a processor, an internal bus, a network interface, a memory and a nonvolatile storage, and may also include hardware required by other services. The processor reads the corresponding computer program from the nonvolatile memory into the memory and then runs the computer program to realize the obstacle detection method according to any embodiment.

Based on the method for detecting an obstacle according to any of the above embodiments, the present application further provides a schematic structural diagram of a movable platform as shown in fig. 9. At the hardware level, as in fig. 9, the mobile platform includes a fuselage, a power component, a radar, a processor, an internal bus, a network interface, a memory, and a non-volatile storage, although other hardware required for the business is possible. Wherein the power assembly is used for driving the movable platform to move in space; the detection direction of the radar may be changed with respect to the movable platform. The processor reads the corresponding computer program from the nonvolatile memory into the memory and then runs the computer program to realize the method for detecting the obstacle according to any embodiment.

The application also provides a computer program product, which comprises a computer program, and the computer program can be used for executing the obstacle detection method in any embodiment when being executed by a processor.

Based on the method for detecting an obstacle according to any of the foregoing embodiments, the present application further provides a computer storage medium storing a computer program, where the computer program is executable by a processor to perform the method for detecting an obstacle according to any of the foregoing embodiments.

For the device embodiments, reference is made to the description of the method embodiments for the relevant points, since they essentially correspond to the method embodiments. The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing has outlined rather broadly the methods and apparatus provided in embodiments of the present application in order that the detailed description of the principles and embodiments of the present application may be implemented in any way that is used to facilitate the understanding of the method and core concepts of the present application; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present application, the present description should not be construed as limiting the present application in view of the above.

Claims

A detection method of an obstacle applied to a movable platform carrying a radar whose detection direction is changeable with respect to the movable platform, characterized by comprising:

acquiring the moving direction of the movable platform;

Based on the moving direction, a horizontal detection direction of the radar is controlled so that the radar detects an obstacle in the moving direction.
The method of claim 1, wherein said controlling a horizontal detection direction of the radar comprises one or more of:

Controlling the mechanical rotation of the radar in the horizontal direction; or (b)

Controlling the phase of the radar transmitting beam to control the horizontal detection direction of the radar; or (b)

And controlling yaw rotation of the cradle head carrying the radar.
The method according to claim 1, wherein the method further comprises:

and controlling the vertical detection direction of the radar so as to control the detection direction of the radar to be parallel to the ground.
A method according to claim 3, wherein said controlling the vertical detection direction of the radar comprises one or more of:

controlling the mechanical rotation of the radar in the vertical direction; or (b)

Controlling the phase of the radar transmitting beam to control the vertical detection direction of the radar; or (b)

And controlling the pitching rotation of the cradle head carrying the radar.
The method according to claim 1, wherein an angle range covered by the beam emitted by the radar single frame in the horizontal detection direction is not smaller than a horizontal detection range preset in the moving direction, the controlling the horizontal detection direction of the radar includes:

and controlling the horizontal detection direction of the radar to be consistent with the moving direction.
The method according to claim 1, wherein an angular range covered by the beam emitted by the radar in the horizontal detection direction is smaller than a horizontal detection range preset in the moving direction, the controlling the horizontal detection direction of the radar so that the radar detects an obstacle in the moving direction includes:

and controlling the radar to detect obstacles respectively in different angle ranges of the horizontal detection range.
The method of claim 6, wherein the controlling the radar to detect obstacles within different angular ranges of the detection range, respectively, comprises:

Controlling the radar to detect obstacles in different angle ranges according to preset detection parameters; the detection parameters include one or more of the angular ranges, a detection time for each angular range, or a detection order between angular ranges.
The method according to claim 1, wherein the method further comprises:

and if an obstacle exists in the moving direction, controlling the horizontal detection direction of the radar to face the obstacle.
The method of claim 8, wherein if the obstacle is a plurality of obstacles, the controlling the horizontal detection direction of the radar toward the obstacle comprises:

Controlling the horizontal detection direction of the radar to sequentially face a plurality of obstacles based on a preset detection priority order; the detection priority sequence comprises one or more of direction priority of the obstacle, detection signal amplitude priority of the obstacle and distance priority of the obstacle and the movable platform; or (b)

Controlling the horizontal detection direction of the radar to face an obstacle with the highest priority based on a preset detection priority sequence; the detection priority order comprises one or more of direction priority of the obstacle, detection signal amplitude priority of the obstacle and distance priority of the obstacle and the movable platform.
The method of claim 8, wherein the method further comprises:

Controlling the radar to track the obstacle in the moving direction.
The method according to claim 1, characterized in that the step of controlling the horizontal detection direction of the radar based on the movement direction so that the radar detects an obstacle in the movement direction is performed in case at least one of the following conditions is fulfilled:

The number of obstacles in other directions than the moving direction is less than a preset number threshold;

the distance between the obstacle and the movable platform in other directions except the moving direction is larger than a preset distance threshold;

The number of the obstacles in the moving direction is larger than a preset number threshold;

a preset landform exists in a preset distance in the moving direction;

the moving speed of the movable platform is greater than a preset speed threshold.
The method of claim 1, wherein the method further comprises;

And if the number of the obstacles in other directions except the moving direction is more than a preset number threshold value and/or the moving speed of the movable platform is less than a preset speed threshold value, controlling the radar to detect the obstacles in the moving direction and other directions.
Method according to any of claims 8-12, wherein the movable platform is further equipped with a sensor for detecting obstacles in addition to the radar, the obstacles and/or the preset topography being detected on the basis of the sensor; or alternatively

The obstacle and/or the preset topography is determined based on a map.
The method according to claim 1, wherein the method further comprises:

And planning the moving track of the movable platform based on the obstacle detected by the radar.
An obstacle detection device mounted on a movable platform, the movable platform being mounted with a radar whose detection direction is changeable with respect to the movable platform, the device comprising:

A processor;

A memory for storing processor-executable instructions;

wherein the processor, when invoking the executable instructions, performs the operations of the method of any of claims 1-14.
A movable platform, comprising:

A body;

A power assembly for driving the movable platform to move in space;

A radar whose detection direction is changeable with respect to the movable platform;

A processor;

A memory for storing processor-executable instructions;

wherein the processor, when invoking the executable instructions, performs the operations of the method of any of claims 1-14.
A computer program product comprising a computer program, characterized in that the computer program, when executed by a processor, implements the steps of the method of any of claims 1-14.
A computer readable storage medium having stored thereon computer instructions which, when executed, perform the method of any of claims 1-14.