WO2023155195A1

WO2023155195A1 - Obstacle detection method and device, movable platform, and program product

Info

Publication number: WO2023155195A1
Application number: PCT/CN2022/077104
Authority: WO
Inventors: 王石荣; 王俊喜; 王春明
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2022-02-21
Filing date: 2022-02-21
Publication date: 2023-08-24
Also published as: CN117916631A

Abstract

An obstacle detection method and device, a movable platform, a program product, and a computer readable storage medium. The method is applied to a movable platform carrying a radar, and comprises: obtaining a moving direction of a movable platform (310); and controlling the horizontal detection direction of the radar on the basis of the moving direction, so that the radar detects an obstacle in the moving direction (320). In this way, the radar keeps continuous detection in the moving direction, so that an obstacle having weak signal energy can also be continuously detected to increase the energy of a signal reflected by the obstacle, thereby improving the detection probability of obstacles, and improving the performance of the movable platform for detecting the obstacles.

Description

Obstacle detection method, device, movable platform and program product

technical field

The present application relates to the technical field of movable platforms, in particular to an obstacle detection method, device, movable platform and program product.

Background technique

Mobile platforms such as unmanned vehicles, drones, and robots have been widely used in many fields. In order to control the mobile platform to move safely in space, the mobile platform is often equipped with various sensors for obstacle avoidance, such as binocular vision system, radar, etc. The radar signals reflected by small obstacles such as wires and branches in space tend to have weak energy. If the radar cannot perceive such obstacles with weak signal energy in time, the operation safety of the mobile platform will be affected.

Contents of the invention

In view of this, one of the objectives of the present application is to provide an obstacle detection method, device, mobile platform and program product, so as to improve the performance of the mobile platform in detecting obstacles.

In order to achieve the above technical effects, the embodiments of the present invention disclose the following technical solutions:

In a first aspect, a method for detecting obstacles is provided, which is applied to a movable platform, and the movable platform is equipped with a radar whose detection direction can be changed relative to the movable platform, and the method includes:

Acquiring the moving direction of the movable platform;

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

In a second aspect, an obstacle detection device is provided, which is mounted on a movable platform, and the movable platform is equipped with a radar whose detection direction can be changed relative to the movable platform, and the device includes:

processor;

memory for storing processor-executable instructions;

Wherein, when the processor invokes the executable instruction, the operations of the method of the first aspect are realized.

In a third aspect, a mobile platform is provided, including:

body;

a power assembly, used to drive the movable platform to move in space;

a radar whose detection direction is changeable relative to the movable platform;

processor;

memory for storing processor-executable instructions;

Wherein, when the processor invokes the executable instruction, the operations of the method of the first aspect are implemented.

In a fourth aspect, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps of the method described in the first aspect are implemented.

According to a fifth aspect, a computer-readable storage medium is provided, where several computer instructions are stored on the computer-readable storage medium, and when the computer instructions are executed, the method described in the first aspect is executed.

The present application provides an obstacle detection method, device, movable platform, and program product, which are applied to a movable platform equipped with a radar, and control the horizontal detection direction of the radar based on the moving direction of the movable platform, so that the radar keeps Detect obstacles in the direction of movement. In this way, since the radar keeps detecting continuously in the direction of movement, obstacles with weak signal energy can also be continuously detected to increase the energy of the signal reflected by the obstacle, thereby increasing the detection probability of such obstacles, and improving The ability of the movable platform to detect obstacles.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is a structural diagram of an unmanned aerial system according to an embodiment of the present application.

Fig. 2 is a schematic diagram showing the coverage angle range of a radar transmitting beam according to an embodiment of the present application.

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

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

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

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

Fig. 7 is a flow chart of an obstacle detection method according to another embodiment of the present application.

Fig. 8 is a schematic structural diagram of an obstacle detection device according to an embodiment of the present application.

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

Detailed ways

The technical solutions in the embodiments of the application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Mobile platforms such as unmanned vehicles, drones, and robots have been widely used in many fields. In order to control the movable platform to move safely in space, the movable platform is often equipped with various sensors for obstacle avoidance, such as binocular vision system, radar, infrared sensor or TOF (Time of flight, time of flight) sensor, etc. wait. In practical applications, based on different products, usage scenarios and requirements, different mobile platforms are equipped with different types of sensors.

A mobile platform may refer to any device capable of moving, and examples may include, but are not limited to, land vehicles, water vehicles, air vehicles, and other types of motorized vehicles. As an example, the movable platform may include a passenger vehicle and/or an unmanned aerial vehicle (Unmanned Aerial Vehicle, UAV), etc., and the movement of the movable platform may include flying.

Taking unmanned aerial vehicles as an example, FIG. 1 is a schematic architecture diagram of an unmanned aerial system. This embodiment takes a rotorcraft as an example for illustration. The unmanned aerial system 100 may include an unmanned aerial vehicle 110, A display device 130 and a remote control device 140 . Wherein, the unmanned aerial vehicle 110 may include a power system 150, a flight control system 160, a frame and a pan-tilt 120 carried on the frame. The drone 110 can communicate wirelessly with the remote control device 140 and the display device 130 .

The frame may include the fuselage and undercarriage (also known as 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 tripod is connected with the fuselage and is used for supporting the UAV 110 when it lands.

The power system 150 may include one or more electronic governors (abbreviated as ESCs) 151, one or more propellers 153 and one or more power motors 152 corresponding to the one or more propellers 153, wherein the power motor 152 Connected between the electronic governor 151 and the propeller 153, the power motor 152 and the propeller 153 are arranged on the machine arm of the drone 110; the electronic governor 151 is used to receive the driving signal generated by the flight control system 160, and according to the driving The signal provides driving current to the power motor 152 to control the speed of the power motor 152 . The power motor 152 is used to drive the propeller to rotate, so as to provide power for the flight of the UAV 110 , and the power enables the UAV 110 to realize movement of one or more degrees of freedom. In some embodiments, drone 110 may rotate about one or more axes of rotation. For example, the rotation axis may include a roll axis (Roll), a yaw axis (Yaw) and a pitch axis (pitch). It should be understood that the motor 152 may be a DC motor or an AC motor. In addition, the motor 152 can be a brushless motor or a brushed motor.

Flight control system 160 may include flight controller 161 and sensing system 162 . One of the functions of the sensing system 162 is to measure the attitude information of the UAV, which is the position information and status information of the UAV 110 in space, such as three-dimensional position, three-dimensional angle, three-dimensional velocity, three-dimensional acceleration and three-dimensional angular velocity etc. Sensor systems can also serve other purposes, such as collecting environmental observations of the drone's surroundings. Sensing system 162, for example, may include one or more of the following: gyroscope, ultrasonic sensor, electronic compass, inertial measurement unit (Inertial Measurement Unit, IMU), visual sensor, infrared sensor, TOF (Time of Flight, time of flight) sensor , lidar, millimeter-wave radar, thermal imagers, global navigation satellite systems, barometers, and more. For example, the global navigation satellite system may be the Global Positioning System (GPS). The flight controller 161 is used to control the flight of the UAV 110 , for example, the flight of the UAV 110 can be controlled according to the attitude information measured by the sensing system 162 . It should be understood that the flight controller 161 can control the UAV 110 according to pre-programmed instructions, or can control the UAV 110 by responding to one or more remote control signals from the remote control device 140 .

The gimbal 120 may include a motor 122 . The gimbal can be used to carry loads, such as the camera 123 and the like. The flight controller 161 can control the movement of the gimbal 120 through the motor 122 . Optionally, as another embodiment, the pan-tilt 120 may further include a controller for controlling the movement of the pan-tilt 120 by controlling the motor 122 . It should be understood that the gimbal 120 may be independent of the UAV 110 or be a part of the UAV 110 . It should be understood that the motor 122 may be a DC motor or an AC motor. In addition, the motor 122 may be a brushless motor or a brushed motor. It should also be understood that the gimbal can be located on top of the drone or on the bottom of the drone.

The photographing device 123 can be, for example, a camera or a video camera or other equipment for capturing images. The photographing device 123 can communicate with the flight controller and take pictures under the control of the flight controller. The photographing device 123 in this embodiment includes at least a photosensitive element, such as a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) sensor or a charge-coupled device (Charge-coupled Device, CCD) sensor. It can be understood that the camera device 123 can also be directly fixed on the drone 110, so that the pan-tilt 120 can be omitted.

The display device 130 is located at the ground end of the UAV 100 , can communicate with the UAV 110 wirelessly, and can be used to display the attitude information of the UAV 110 . In addition, the image captured by the capturing device 123 may also be displayed on the display device 130 . It should be understood that the display device 130 may be an independent device, or may be integrated in the remote control device 140 .

The remote control device 140 is located at the ground end of the unmanned aerial system 100 , and can communicate with the UAV 110 in a wireless manner for remote control of the UAV 110 .

It should be understood that the above naming of the various components of the unmanned aerial vehicle system is only for the purpose of identification, and should not be construed as limiting the embodiments of the present application.

In some scenarios, mobile platforms such as consumer drones can be equipped with radar for obstacle avoidance. Among them, the radar is composed of a transmitter, a receiver, and an information processing system. It can transmit a detection signal (beam) and receive a signal reflected from an obstacle, and obtain the spatial position of the obstacle according to the reflected signal, including distance, angle, Speed, energy and other information. Radars may include, but are not limited to, phased array radars, rotating radars, microwave radars, millimeter wave radars, and the like. In certain scenarios, compared with other sensors, microwave radar has a longer detection distance and can detect smaller obstacles, such as 0.5mm wires.

In order to achieve omnidirectional obstacle avoidance, the movable platform is often equipped with a radar whose detection direction can be changed relative to the movable platform. Wherein, the detection direction may include a horizontal detection direction and a vertical detection direction. The horizontal detection direction may refer to the detection direction parallel to the horizontal plane of the movable platform coordinate system (body system); the vertical detection direction may refer to the detection direction perpendicular to the horizontal plane of the movable platform coordinate system. The detection direction of the radar can be changed relative to the movable platform, and the horizontal detection direction of the radar can be changed relative to the movable platform, and/or the vertical detection direction of the radar can be changed relative to the movable platform. As shown in Figure 2, one frame of radar transmission beam can cover a certain angle range, including the horizontal angle range covered in the horizontal detection direction, and the vertical angle range covered in the vertical detection direction. Wherein, the horizontal angle range and the vertical angle range may be the same or different angle ranges, for example, the horizontal angle range may be larger than the vertical angle range.

There are many ways to change the detection direction of the radar. For example, the above-mentioned rotating radar can change the detection direction of the radar through mechanical rotation; and the above-mentioned phased array radar can change the detection direction of the radar by controlling the phase of the transmitted beam. During the operation of the movable platform, the radar can continuously change the detection direction to achieve omnidirectional obstacle avoidance (rotation mode). Taking the rotating radar as an example, the rotating radar can achieve 360° omnidirectional detection through mechanical rotation. In the rotation mode, the rotating radar can rotate several times per second, such as 15 times, then within one rotation, the radar can only emit beams with a small number of frames in each direction. However, for small obstacles such as wires and branches in space, the energy of the reflected signal is weak, and it is difficult for radar to detect such obstacles through the echo signal of a single frame. In some scenarios, when the movable platform moves at a high speed, such as when the UAV is flying at high speed, if the radar cannot detect these obstacles and the UAV collides with it, the parts of the UAV will be damaged. , Even cause the crash and loss of the plane, which is a great hidden danger to the safe flight of the drone.

To this end, the present application proposes an obstacle detection method, which is applied to a mobile platform, such as a drone equipped with an unmanned aerial system as shown in FIG. 1 . The movable platform is equipped with a radar whose detection direction can be changed relative to the movable platform, such as rotating radar, phased array radar and other radars whose detection direction can be changed. Described method comprises the steps as shown in Figure 3:

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

Step 320: Based on the moving direction, control the horizontal detection direction of the radar, so that the radar detects obstacles in the moving direction.

As mentioned above, the detection direction of radar can be decomposed into horizontal detection direction and vertical detection direction. The horizontal detection direction of the above-mentioned radar may be a detection direction parallel to the horizontal plane of the movable platform coordinate system (body system). Controlling the horizontal detection direction of the radar may be to control 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 moving direction of the movable platform may or may not be consistent with the head orientation of the movable platform. Taking the drone as an example, when the drone is flying forward, the direction of movement (flight direction) of the drone can be consistent with the direction of the nose of the drone. When the drone is flying sideways, the movement direction of the drone The direction can be inconsistent with the direction of the nose of the drone. When taking off or landing, the direction of movement of the drone is not consistent with the nose of the aircraft.

The beam emitted by the radar can be reflected by obstacles to form an echo signal. After the radar receives the echo signal, it can process the echo signal and detect obstacles. The processing of the echo signal may include but not limited to DC isolation, amplitude and phase calibration, signal windowing, distance dimension Fast Fourier transform (Fast Fourier transform, FFT), velocity dimension FFT, angle dimension FFT, constant false alarm detection ( Constant False-Alarm Rate, CFAR) and peak detection to detect obstacles. For the above signal processing process, reference may be made to related technologies, which will not be discussed in this application.

The obstacle detection method provided in this embodiment controls the horizontal detection direction of the radar based on the moving direction of the movable platform, so that the radar keeps detecting obstacles in the moving direction. The working mode of controlling the radar to keep detecting obstacles in the moving direction can be called the fire control mode of the radar. Compared with the rotation mode, since the radar keeps detecting continuously in the moving direction, the amplitude of the signal reflected by the obstacle can be accumulated in time to improve the signal-to-noise ratio of the reflected signal. Therefore, for obstacles with weak signal energy, the energy of the signal reflected by the obstacle can also be increased by continuous detection, thereby increasing the detection probability of such obstacles and improving the performance of the movable platform to detect obstacles.

In some scenarios, if a part of the beam emitted by the radar is reflected by the ground, since the signal energy reflected by the ground is relatively large, it may cover the echo signals reflected by other obstacles, thereby causing detection interference. To this end, in some embodiments, the above method may further include the step of: controlling the vertical detection direction of the radar, so as 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 the horizontal plane of the movable platform coordinate system.

As an example, if the terrain where the mobile platform is located is a horizontal plane, the vertical detection direction of the radar is controlled to be parallel to the horizontal plane; The terrain information is obtained from the experimental information, such as terrain slope, slope and other information, and based on the terrain information, the vertical detection direction of the radar is controlled to be parallel to the ground. Wherein, the sensors for acquiring terrain information may include but not limited to sensors such as image sensors and laser radars. In this way, when the detection direction of the radar is parallel to the ground, the beam emitted by the radar will not be reflected by the ground, thereby avoiding the cover of the echo signal of the obstacle.

In some other embodiments, the echo signal received by the radar may also be filtered to remove the echo signal reflected by the ground. Specifically, terrain information, such as terrain slope, slope, and the like, may be obtained based on prior information such as sensors mounted on a movable platform or maps. And based on the terrain information, the echo signal reflected by the ground is filtered from the received echo signal, thereby avoiding the cover of the obstacle echo signal.

In some embodiments, the radar onboard the movable platform may be a rotating radar. Fig. 4 shows a cross-sectional view of an exemplary rotating radar. The rotating radar 400 includes a cover body 410, a fixed bracket 420 is arranged in the cover body 410, and a motor is installed on the fixed bracket 420. The motor includes a stator 430 and a rotor 440. , a rotating bracket 450 is installed on the rotor 440, and the rotating bracket 450 rotates together with the rotor 440 of the motor; an antenna structure 460 and an antenna controller 470 are installed on the rotating bracket 450, and the antenna controller 470 is used to control the antenna structure 460 transmits and receives radar signals.

Further, in some implementations, the rotation radar 400 further includes an angle sensor 480 for detecting the rotation angle of the rotor 440 . The angle sensor 480 can be one or more of Hall sensor, potentiometer and encoder. It can be understood that the angle sensor 480 detects the rotation angle of the rotor 440 , that is, detects the rotation angle of the rotation radar 400 . The device using the rotating radar 400 can assist in judging the emission direction of the radar signal and the direction of the received radar signal according to the rotation angle of the rotating radar 400, and further judge the relative direction of the obstacle and the device using the rotating radar 400.

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

As an example, the rotating bracket 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 rotating radar 400 in the vertical direction can be controlled by controlling the mechanical rotation of the rotating radar 400 around the rotating bracket 450 , thereby controlling the vertical detection direction of the radar.

In some embodiments, the radar onboard the movable platform may be a phased array radar. The antenna front of the phased array radar includes multiple radiating units and receiving units. The phase of the current fed to each radiating unit is controlled by a computer. Based on the principle of electromagnetic wave coherence, the phased array radar can radiate beams with different directions in space. In this way, the phased array radar can control the horizontal detection direction and/or the vertical detection direction of the radar by controlling the phase of the transmitting beam. For a specific phase control method, reference may be made to related technologies, and the present application will not describe it in detail here.

In some embodiments, the radar can be mounted on a movable platform via a gimbal. Wherein, the gimbal can be a two-axis gimbal or a three-axis gimbal. For example, it may be the pan/tilt 120 shown in FIG. 1 . The gimbal may include a yaw (yaw) axis motor, a pitch (pitch) axis motor, a yaw axis arm, and a pitch axis arm. The yaw axis arm is used to support the yaw axis motor, and the pitch axis arm is used to support the pitch axis motor. As an example, the horizontal detection direction of the radar can be controlled by controlling the yaw rotation of the gimbal around the yaw axis arm. As an example, the vertical detection direction of the radar can be controlled by controlling the gimbal to rotate around the pitch axis of the pitch axis arm.

In some embodiments, the radar mounted on the movable platform may be a rotating phased array radar, that is, the radar can not only rotate mechanically around the rotating support, but also control the phase of the transmitting beam. In this embodiment, the rotating bracket of the rotating phased array radar can be set perpendicular to the horizontal plane of the movable platform coordinate system, and the rotating phased array radar can be controlled in the horizontal direction by controlling the mechanical rotation of the rotating phased array radar around the rotating bracket. The mechanical rotation of the radar controls the horizontal detection direction of the radar; the vertical detection direction of the rotating phased array radar is controlled by controlling the phase of the transmitted beam.

As mentioned above, the beam emitted by a single frame of the radar can cover a certain angle range. In some embodiments, if the angle range covered by the beam emitted by a single frame of the radar in the horizontal detection direction is not less than the preset For the horizontal detection range, in step 320, the horizontal detection direction of the radar is controlled based on the moving direction, which may be to control the horizontal detection direction of the radar to be consistent with the moving direction. Wherein, the preset horizontal detection range in the moving direction may be an angle range set to ensure the safety of the movable platform, for example, 30°. For another example, the preset horizontal detection range in the moving direction may have a negative correlation with the moving speed of the movable platform. That is, the greater the moving speed of the mobile platform, the smaller the horizontal detection range.

In some other embodiments, if the angle range covered by the beam emitted by a single frame of the radar in the horizontal detection direction is smaller than the preset horizontal detection range in the moving direction of the movable platform, then in step 320, the horizontal detection of the radar is controlled based on the moving direction The direction can be used to control the radar to detect obstacles in different angle ranges of the horizontal detection range. Since the angle range covered by the beam emitted by a single frame of the radar in the horizontal detection direction is smaller than the preset horizontal detection range, the radar needs to perform multiple detections in multiple frames within the horizontal detection range to cover the entire horizontal detection range.

As an example, if the preset horizontal detection range is 180°, and the beam emitted by a single frame of the radar can only cover a range of 30° to 40° in the horizontal detection direction, the radar can detect several frames in different angle ranges. Covers the entire horizontal detection range. For example, the detection is carried out at 15° to the left, 45° to the left, 90° to the left, 15° to the right, 45° to the right, and 90° to the right to cover the entire horizontal detection range.

In some embodiments, the control radar detects obstacles in different angle ranges of the horizontal detection range, and the control radar may detect obstacles in different angle ranges according to preset detection parameters. Wherein, the detection parameters may include but not limited to one or more of the angle range, the detection time of each angle range, or the detection sequence between the angle ranges.

As an example, as shown in FIG. 5 , the preset horizontal detection range in the moving direction of the movable platform is 120°. However, the beam emitted by a single frame of the radar can only cover an angular range of about 30° in the horizontal detection direction. Then the preset horizontal detection range can be divided into four angle ranges A-D as shown in FIG. 5 . Among them, the angular ranges covered by the angular ranges A-D can be the same or different, and there can be overlapping angular ranges or no overlapping angular ranges between two adjacent angular ranges, as long as all angular ranges can cover the entire horizontal detection range. In addition, the detection time of each angle range can be set, for example, the number of seconds or the number of frames of detection for each angle range can be set. The detection times for different angular ranges can be the same or different. For example, the detection time of angle range A and angle range D is 5 ms, and the detection time of angle range B and angle range C is 10 ms. In addition, the detection sequence among multiple angle ranges may also be set, for example, the detection sequence may be detection from angle range A to angle range D sequentially. In this way, by performing multi-frame detection in different angle ranges by the radar, the entire preset horizontal detection range can be covered, thereby ensuring the safety of the movable platform.

In some embodiments, if there is an obstacle in the moving direction, the horizontal detection direction of the radar can be controlled to face the obstacle, so that the direction with the strongest transmit beam gain points to the obstacle, thereby increasing the strength of the reflected signal of the obstacle, Improve the detection probability of obstacles. Optionally, after the horizontal detection direction of the radar faces the obstacle for a preset time, the horizontal detection direction of the radar is controlled to return to the original orientation, that is, the orientation before the obstacle, and the preset time may be 1-3 ms. Optionally, the radar can also be controlled to track obstacles in the moving direction. During the moving process of the movable platform, if it is determined that there is an obstacle in the moving direction, the radar can be controlled to track the detected obstacle when the number of other obstacles in the moving direction is small. As shown in Figure 6(a), taking the UAV as an example, the UAV detects three obstacles in the moving direction based on the radar at the first position. As shown in Figure 6(b), as the UAV flies in the moving direction, the orientation of the obstacle relative to the UAV can be obtained in the second position, and the horizontal detection direction of the radar is adjusted to face the obstacle. In order to realize the tracking of obstacles. The radar can keep tracking the obstacle until the obstacle is away from the moving direction of the movable platform, for example, away from the preset horizontal detection range in the moving direction, then cancel the tracking, and control the horizontal detection direction of the radar to return to the original direction, that is, tracking The previous orientation of this obstacle.

In some embodiments, the obstacle in the moving direction may be detected when the radar detects the obstacle in the moving direction. In some other embodiments, the movable platform is also equipped with sensors for detecting obstacles other than the radar, such as the above-mentioned ultrasonic sensor, visual sensor, infrared sensor, TOF sensor, and the like. Obstacles in the moving direction can also be detected by other sensors. For example, if other sensors detect that there is an obstacle in a certain direction in the moving direction, the other sensors can send the position information of the obstacle directly or through the processor to the radar, so that the horizontal detection direction of the radar faces the obstacle. In some other embodiments, the obstacles in the moving direction may also be determined based on prior information of the map. Wherein, the map can be pre-stored on the mobile platform, or obtained online in real time based on the communication module carried by the mobile platform. For example, based on the location of the movable platform, the environmental information near the location can be obtained from the prior information of the map, and whether there are obstacles around the movable platform, such as utility poles and street lights, can be determined from the environmental information, and obtained The relative position information of the obstacle and the movable platform, so that the horizontal detection direction of the radar can be controlled to face the obstacle.

In some scenarios, if there are multiple obstacles, the horizontal detection directions of the radar can be controlled to face the obstacles respectively, so that the direction with the strongest transmitting beam gain points to each obstacle one by one. Among them, if the angle range covered by the beam emitted by the radar in a single frame in the horizontal detection direction is not less than the preset horizontal detection range in the moving direction of the movable platform, then the radar can detect multiple obstacles in at least one frame of detection , and can control its horizontal detection direction to detect each obstacle respectively. If the angle range covered by the beam emitted by a single frame of the radar in the horizontal detection direction is smaller than the preset horizontal detection range in the moving direction of the movable platform, the radar can only cover the entire horizontal detection range by detecting obstacles in different angle ranges of the horizontal detection range. The detection range, then the radar can only find all obstacles in the entire horizontal detection range in multi-frame detection. In this way, the radar can be controlled to detect obstacles in different angle ranges according to the preset detection parameters until the detection of the entire horizontal detection range is completed, so as to find obstacles in the entire horizontal detection range. Then control the horizontal detection direction of the radar to face each obstacle respectively. As in the example shown in Figure 5, the angle range A-D can be scanned in the detection order first, and after all obstacles in the entire horizontal detection range are found, the horizontal detection direction of the radar is controlled to face each obstacle respectively. Alternatively, when the radar detects different angle ranges according to the detection parameters, if the radar detects an obstacle, the horizontal detection direction of the radar is controlled to face the discovered obstacle, that is, it is not necessary to complete the detection of the entire horizontal detection range first . In the example shown in Figure 5, the radar detects the entire horizontal detection range according to the detection sequence from angle range A to angle range D. If obstacles are found in the angle range B, the horizontal detection direction of the radar can be directly controlled. For the obstacle, after completing the data acquisition of the obstacle, continue to complete the detection of the angle range C and the angle range D according to the detection sequence.

In some embodiments, if the radar detects multiple obstacles, including detecting multiple obstacles within the entire horizontal detection range, or detecting multiple obstacles within a certain angle range, it can be based on the preset detection Priority order, control the horizontal detection direction of the radar to face multiple obstacles in turn or control the horizontal detection direction of the radar to only face the obstacle with the highest priority.

As an example, the detection priority order may include a directional priority of obstacles. Optionally, the closer the obstacle is to the moving direction, the higher the detection priority is. As in the above example, if obstacles appear in all angle ranges A-D, the detection priority of obstacles in angle ranges B and C is higher than that in angle ranges A and D. Since the movable platform has a greater probability of colliding with obstacles appearing in the direction of movement, the safety of movement can be ensured by prioritizing the detection of obstacles approaching the direction of movement.

Optionally, the direction priority of the obstacle may also be consistent with the detection order among multiple angle ranges, so as to simplify the calculation resources of the detection priority order. As in the above example, if obstacles appear in all the angle ranges A-D, then the obstacles in each angle range can 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 obstacles. For example, the detection priority of an obstacle with a high detection signal amplitude is higher than that of an obstacle with a low detection signal amplitude. Compared with obstacles with low detection signal amplitude, radar can complete the data collection of obstacles with high detection signal amplitude in a shorter time. Therefore, obstacles with high signal amplitudes are preferentially detected, and more obstacles can be detected in a short period of time, thereby improving the detection performance of the movable platform for obstacles.

As an example, the detection priority order may include a distance priority of obstacles to the movable platform. For example, the detection priority of obstacles with a small distance from the movable platform is higher than that of obstacles with a large distance. Prioritize the detection of obstacles closer to the mobile platform, so that the mobile platform can make obstacle avoidance decisions based on the obstacle information to avoid collisions between the mobile platform and obstacles.

As an example, the detection priority order may include a combination of the direction priority of the obstacle, the detection signal amplitude priority of the obstacle, and the distance priority between the obstacle and the movable platform. For example, the detection priority of each obstacle may be firstly determined according to the distance between the obstacle and 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. There may be multiple combinations of various priorities, which are not limited to the examples listed above. Those skilled in the art can make combinations according to actual needs, which is not limited in this application.

As mentioned above, during the operation of the movable platform, the radar can continuously change the detection direction in the rotation mode to achieve omnidirectional obstacle avoidance; in the fire control mode, it can keep detecting obstacles in the moving direction. In some embodiments, when any of the following conditions are satisfied, the radar can be controlled to enter the fire control mode, such as switching from the rotation mode to the fire control mode, so as to maintain continuous detection in the moving direction.

Condition 1: The number of obstacles in directions other than the moving direction is less than a preset number threshold. Taking the forward movement of the movable platform as an example, other directions may include but not limited to the left and right sides, top and bottom of the movable platform. If the number of obstacles in other directions is small, the radar can be controlled to enter the fire control mode to keep detecting obstacles in the moving direction.

Condition 2: The distance between obstacles in other directions except the moving direction and the movable platform is greater than a preset distance threshold. If there are obstacles in other directions, but the distance between the obstacle and the movable platform is large enough to not affect the safe movement of the movable platform, the radar can be controlled to enter the fire control mode to keep detecting obstacles in the moving direction.

Condition 3: The number of obstacles in the moving direction is greater than a preset number threshold. Wherein, the preset quantity threshold may be consistent with the quantity threshold in condition 1, or may be two thresholds with different sizes. If there are many obstacles in the moving direction, it will affect the safe movement of the movable platform, and the radar can be controlled to enter the fire control mode to keep detecting obstacles in the moving direction.

Condition 4: There is a preset landform within a preset distance in the moving direction. Wherein, the preset landforms may include but not limited to landforms with large terrain fluctuations, including landforms with many surface buildings or trees. As an example, the preset landform may be one or more of woodland, city, mountain, and farmland. Because the terrain is too undulating, or there are many surface buildings and trees, the movable platform is easy to collide with the undulating terrain, or collide with the surface buildings, trees, etc. during the movement, so the radar can be controlled to enter the fire control mode, keep in the moving direction for continuous detection.

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 mobile platform is high, obstacles that are difficult to detect will become a more serious collision threat to the mobile platform, and the probability of structural damage to the mobile platform after collision with obstacles is higher. The mobile platform needs to obtain the information of obstacles in the moving direction in a more timely manner to make obstacle avoidance planning. Therefore, when the moving speed of the movable platform is relatively high, the radar can be controlled to enter the fire control mode to keep detecting obstacles in the moving direction.

Condition 6: The movable platform can predict the moving direction within a preset time period. In the fire control mode, the radar needs to keep continuous detection in the direction of movement. If the moving direction of the movable platform is constantly changing, the movable platform may not be able to adjust the horizontal detection direction of the radar to the moving direction of the movable platform in time. Taking drones as an example, when the drone is in manual flight mode, its flight freedom is relatively large, and the drone cannot predict where the user will control the drone to fly to at the next moment, that is, it cannot predict the flight trajectory. And the flight direction is predicted, so it is difficult to control the radar to keep the detection in the flight direction at all times. In this way, if the movable platform moves according to the pre-planned trajectory, or the movable platform moves to the set target, the mobile platform can predict the movement direction at the next moment according to the pre-planned trajectory or the set target, so that it can control The radar keeps detecting in the direction of movement at all times.

Among them, before entering the fire control mode, information on obstacles in the direction of movement and in directions other than the direction of movement includes quantity information, distance information, and terrain information within a preset distance in the direction of movement. As an example, the above Information may be based on radar detection. For example, the radar performs omnidirectional detection in rotation mode, and can detect obstacle information and terrain information in all directions. And based on the obstacle information obtained in the rotation mode, it is judged whether the radar enters the fire control mode. In addition, the movable platform can also be equipped with sensors for detecting obstacles other than radar, such as the above-mentioned ultrasonic sensor, visual sensor, infrared sensor, TOF sensor, etc. As an example, the above information may be obtained based on other sensor detections. For example, other sensors can detect obstacle information in different directions, and the movable platform can judge whether the radar enters the fire control mode based on the obtained obstacle information. As an example, the above information may also be determined based on prior information of the map. Wherein, the map can be pre-stored on the mobile platform, or obtained online in real time based on the communication module carried by the mobile platform. For example, based on the location of the mobile platform, the environmental information near the location can be obtained from the prior information of the map, and whether there are obstacles around the mobile platform, such as utility poles, street lights, etc., can be obtained from the environmental information. Based on the obstacle information obtained from the map, it can be judged whether the radar enters the fire control mode.

In some embodiments, when any of the following conditions are met, the radar can be controlled to enter the rotation mode, for example, switch from the fire control mode to the rotation mode, so as to realize omnidirectional obstacle avoidance.

Condition 7: The number of obstacles in directions other than the moving direction is greater than a preset number threshold. If there are many obstacles in other directions, it will affect the safe movement of the movable platform. You can control the radar to enter the rotation mode to obtain a larger detection range and prevent obstacles from colliding with the movable platform.

Condition 8: The distance between obstacles in other directions except the moving direction and the movable platform is smaller than a preset distance threshold. If obstacles in other directions are closer to the movable platform, it is easy to cause the movable platform to collide with obstacles. Therefore, the radar can be controlled to enter the rotation mode to detect obstacles in the moving direction and other directions to achieve omnidirectional obstacle avoidance. .

Condition 9: The moving speed of the movable platform is less than a preset speed threshold. When the moving speed of the movable platform is small, a larger detection range can be obtained to ensure the omnidirectional safety of the movable platform, so the radar can be controlled to enter the rotation mode to detect obstacles in the moving direction and other directions to achieve omnidirectional avoidance barrier.

Condition 10: The movable platform is in manual control mode. As mentioned above, when the movable platform is in the manual control mode, due to the large degree of freedom of movement, the movable platform cannot predict the moving position and moving direction at the next moment, so the radar can be controlled to enter the rotation mode, in the moving direction and Detect obstacles in other directions to achieve omnidirectional obstacle avoidance.

Wherein, before entering the rotation mode, the obstacle information in other directions includes quantity information and distance information. As an example, the above information can be obtained based on other sensors for detecting obstacles mounted on the movable platform. The movable platform can judge whether the radar enters the rotation mode based on the obstacle information collected by other sensors in other directions. As an example, the above information may also be determined based on prior information of the map. The movable platform can judge whether the radar enters the rotation mode based on the obstacle information obtained from the map in other directions.

In some embodiments, when the radar detects an obstacle in the moving direction and collects enough information about the obstacle, the movable platform can plan the trajectory of the movable platform based on the obstacle information collected by the radar. As an example, the IMU (Inertial Measurement Unit, IMU) mounted on the movable platform can be used to obtain the motion information of the movable platform, and combined with the obstacle information to plan or update the movement trajectory.

An obstacle detection method provided by this application is applied on a movable platform equipped with a radar, and the radar can at least detect obstacles in a rotation mode or a fire control mode. In order to improve the detection probability of tiny obstacles, the radar can be controlled to switch from the rotation mode to the fire control mode under certain conditions, and the horizontal detection direction of the radar can be controlled based on the moving direction of the movable platform, so that the radar can keep detecting obstacles in the moving direction things. Since the radar keeps detecting continuously in the moving direction, the signal gain reflected by obstacles can be accumulated in time. Compared with the radar single-frame acquisition signal in the rotation mode, the signal-to-noise ratio of the echo signal can be doubled in the fire control mode, and the gain of the reflected signal can be increased. Therefore, for obstacles with weak signal energy, the energy of the signal reflected by the obstacle can also be increased by continuous detection, thereby increasing the detection probability of such obstacles and improving the performance of the movable platform to detect obstacles.

In addition, the present application also provides a method for detecting obstacles, which is applied to a movable platform equipped with a rotating microwave radar, wherein the rotating bracket of the rotating microwave radar can be set perpendicular to the horizontal plane of the movable platform coordinate system, by controlling The mechanical rotation of the radar around the rotating bracket can control the mechanical rotation of the radar in the horizontal direction. It is also possible to control the vertical detection direction of the radar by controlling the phase of the radar's transmitting beam. The radar can at least detect obstacles in rotation mode or fire control mode. The above method may include steps as shown in Figure 7:

Step 710: The radar enters the rotation mode to detect obstacles in all directions;

As an example, the radar can be controlled to enter the rotation mode to detect the surrounding environment when the movable platform is turned on or started to work.

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

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

If yes, execute step 741; otherwise, execute step 732.

Step 732: Whether the distance between obstacles in other directions than the moving direction and the movable platform is greater than a preset distance threshold;

If yes, execute step 741; otherwise, execute step 733.

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

If yes, execute step 741; otherwise, execute step 734.

Step 734: Whether there is a preset landform within a preset distance in the moving direction;

If yes, execute step 741; otherwise, execute step 735.

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

If yes, execute step 741; otherwise, execute step 736.

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

If yes, execute step 741; otherwise, execute step 710, that is, keep the radar in the rotation mode to detect obstacles omnidirectionally.

Step 741: The radar enters the fire control mode, controls the mechanical rotation of the radar in the horizontal direction, and makes the radar detect obstacles in the moving direction;

Step 742: Control the phase of the radar transmitting beam, so as to control the detection direction of the radar to be parallel to the ground;

Step 743: If there is an obstacle in the moving direction, control the horizontal detection direction of the radar to face the obstacle;

Step 744: Process the echo signal reflected by the obstacle to obtain obstacle information;

Step 745: Based on the obstacle information, plan the trajectory of the movable platform.

In addition, while performing steps 741 to 745, steps 751 to 754 may also be performed at the same time:

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

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

Step 752: Whether the distance between obstacles in directions other than the moving direction and the movable platform is less than a preset distance threshold;

If yes, execute step 710 to switch from the fire control mode to the rotation mode; if not, execute step 753 .

Step 753: Whether the moving speed of the movable platform is less than a preset speed threshold;

If yes, execute step 710 to switch from the fire control mode to the rotation mode; if not, execute step 754 .

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

If yes, execute step 710 to switch from the fire control mode to the rotation mode; if not, return to step 751, that is, execute steps 751-754 in a loop, and the radar keeps operating in the fire control mode.

An obstacle detection method provided by the present application is applied to a movable platform equipped with a radar, and the radar can at least detect obstacles in a rotation mode or a fire control mode. In order to improve the detection probability of tiny obstacles, the radar can be controlled to switch from the rotation mode to the fire control mode under certain conditions, and the horizontal detection direction of the radar can be controlled based on the moving direction of the movable platform, so that the radar can keep detecting obstacles in the moving direction things. Since the radar keeps detecting continuously in the moving direction, the signal gain reflected by obstacles can be accumulated in time. Compared with the radar single-frame acquisition signal in the rotation mode, the signal-to-noise ratio of the echo signal can be doubled in the fire control mode, and the gain of the reflected signal can be increased. Therefore, for obstacles with weak signal energy, the energy of the signal reflected by the obstacle can also be increased by continuous detection, thereby increasing the detection probability of such obstacles and improving the performance of the movable platform to detect obstacles.

Based on the obstacle detection method described in any of the above embodiments, the present application also provides a schematic structural diagram of an obstacle detection device as shown in FIG. 8 . As shown in Figure 8, at the hardware level, the obstacle detection device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory, and of course may also include hardware required by other services. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it, so as to realize the obstacle detection method described in any of the above embodiments.

Based on the obstacle detection method described in any of the above embodiments, the present application also provides a schematic structural diagram of a movable platform as shown in FIG. 9 . As shown in Figure 9, at the hardware level, the mobile platform includes airframe, power components, radar, processor, internal bus, network interface, memory, and non-volatile memory, and of course may also include hardware required by other services. Wherein, the power assembly is used to drive the movable platform to move in space; the detection direction of the radar can be changed relative to the movable platform. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it, so as to realize the obstacle detection method described in any of the above embodiments.

Based on the obstacle detection method described in any of the above embodiments, the present application also provides a computer program product, including a computer program, which can be used to execute one of the above described in any of the embodiments when the computer program is executed by a processor. Obstacle detection method.

Based on the obstacle detection method described in any of the above embodiments, the present application also provides a computer storage medium, the storage medium stores a computer program, and when the computer program is executed by a processor, it can be used to implement the method described in any of the above embodiments. A method for detecting obstacles.

As for the device embodiment, since it basically corresponds to the method embodiment, for related parts, please refer to the part description of the method embodiment. The device embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network elements. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. It can be understood and implemented by those skilled in the art without creative effort.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. The term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements but also other elements not expressly listed elements, or also elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The methods and devices provided by the embodiments of the present application have been described in detail above. The principles and implementation methods of the present application have been explained by using specific examples in this paper. The descriptions of the above embodiments are only used to help understand the methods and methods of the present application. core idea; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be construed as limiting the application .

Claims

A method for detecting obstacles, applied to a movable platform, the movable platform is equipped with a radar whose detection direction can be changed relative to the movable platform, characterized in that the method comprises:

Acquiring the moving direction of the movable platform;

Based on the moving direction, the horizontal detection direction of the radar is controlled so that the radar detects obstacles in the moving direction.
The method according to claim 1, wherein the controlling the horizontal detection direction of the radar comprises one or more of the following:

controlling the mechanical rotation of said radar in the horizontal direction; or

controlling the phase of the radar transmit beam to control the horizontal detection direction of the radar; or

Control the yaw rotation of the gimbal equipped with the radar.
The method according to claim 1, further comprising:

The vertical detection direction of the radar is controlled, so that the detection direction of the radar is controlled to be parallel to the ground.
The method according to claim 3, wherein said controlling the vertical detection direction of said radar comprises one or more of the following:

controlling the mechanical rotation of said radar in the vertical direction; or

controlling the phase of the radar transmit beam to control the vertical detection direction of the radar; or

Control the pitch and rotation of the gimbal equipped with the radar.
The method according to claim 1, wherein the angle range covered by the beam emitted by the radar in a single frame in the horizontal detection direction is not less than the preset horizontal detection range in the moving direction, and the control The horizontal detection direction of the radar includes:

The horizontal detection direction of the radar is controlled to be consistent with the moving direction.
The method according to claim 1, wherein the angular 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 in the moving direction, and the control unit The horizontal detection direction of the radar, so that the radar detects obstacles in the moving direction, including:

The radar is controlled to detect obstacles respectively in different angle ranges of the horizontal detection range.
The method according to claim 6, wherein the controlling the radar to detect obstacles in different angle ranges of the detection range includes:

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

If there is an obstacle in the moving direction, controlling the horizontal detection direction of the radar to face the obstacle.
The method according to claim 8, wherein if there are multiple obstacles, the controlling the horizontal detection direction of the radar to face the obstacle comprises:

Based on the preset detection priority order, the horizontal detection direction of the radar is controlled to face multiple obstacles in sequence; the detection priority order includes the direction priority of obstacles, the detection signal amplitude priority of obstacles, and the obstacle detection priority. one or more of distance priorities from the movable platform; or

Based on the preset detection priority sequence, the horizontal detection direction of the radar is controlled to face the obstacle with the highest priority; the detection priority sequence includes the direction priority of the obstacle, the detection signal amplitude priority of the obstacle, the obstacle One or more of the distance priorities between objects and the movable platform.
The method according to claim 8, characterized in that the method further comprises:

controlling the radar to track the obstacle in the moving direction.
The method according to claim 1, characterized in that, in the case of satisfying at least one of the following conditions, performing the step of controlling the horizontal detection direction of the radar based on the moving direction, so that the radar is in the moving direction Steps to detect obstacles in the direction:

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

The distance between obstacles in directions other than the moving direction and the movable platform is greater than a preset distance threshold;

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

There is a preset landform within a preset distance in the moving direction;

The moving speed of the movable platform is greater than a preset speed threshold.
The method according to claim 1, characterized in that the method further comprises;

If the number of obstacles in directions other than the moving direction is greater than a preset number threshold, and/or the moving speed of the movable platform is lower than a preset speed threshold, control the radar in the moving direction and detect obstacles in other directions.
The method according to any one of claims 8-12, wherein the movable platform is also equipped with sensors for detecting obstacles in addition to the radar, and the obstacles and/or the preset terrain is detected based on said sensor; or

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

Based on the obstacles detected by the radar, the moving trajectory of the movable platform is planned.
A detection device for obstacles, mounted on a movable platform, the movable platform is equipped with a radar whose detection direction can be changed relative to the movable platform, characterized in that the device includes:

processor;

memory for storing processor-executable instructions;

Wherein, when the processor invokes the executable instruction, the operation of the method of any one of claims 1-14 is implemented.
A mobile platform, characterized in that it comprises:

body;

a power assembly, used to drive the movable platform to move in space;

a radar whose detection direction is changeable relative to the movable platform;

processor;

memory for storing processor-executable instructions;

Wherein, when the processor invokes the executable instruction, the operation of the method of any one of claims 1-14 is implemented.
A computer program product, comprising a computer program, characterized in that, when the computer program is executed by a processor, the steps of the method according to any one of claims 1-14 are implemented.
A computer-readable storage medium, characterized in that several computer instructions are stored on the computer-readable storage medium, and the method according to any one of claims 1-14 is executed when the computer instructions are executed.