阅读说明：本技术 一种无人机毫米波雷达探测系统、探测方法及无人机 (Unmanned aerial vehicle millimeter wave radar detection system, detection method and unmanned aerial vehicle ) 是由 王帅 张伟 王雨 张臣勇 车驰 李尧 于 2020-06-18 设计创作，主要内容包括：本发明公开了一种无人机毫米波雷达探测系统、探测方法及无人机,此探测系统包括毫米波雷达和旋转机构,所述旋转机构安装于所述无人机的机身上,所述毫米波雷达安装于所述旋转机构上,并随旋转机构同步旋转。探测方法包括步骤：在无人机飞行过程中,毫米波雷达进行旋转扫描；其中旋转扫描路径为：机身前方-机身下方-机身后方,或者机身后方-机身下方-机身前方；结合无人机飞行状态,雷达旋转扫描得到目标信息,构建飞行立体空间地图。此无人机包括机身和如上所述的无人机毫米波雷达探测系统。本发明具有结构简单、成本低、主动避障、安全可靠、飞行智能化等优点。(The invention discloses an unmanned aerial vehicle millimeter wave radar detection system, a detection method and an unmanned aerial vehicle. The detection method comprises the following steps: in the flight process of the unmanned aerial vehicle, the millimeter wave radar performs rotary scanning; wherein the rotational scan path is: the front part of the machine body, the lower part of the machine body, the rear part of the machine body, or the rear part of the machine body, the lower part of the machine body and the front part of the machine body; and (4) combining the flight state of the unmanned aerial vehicle, obtaining target information through radar rotation scanning, and constructing a flight three-dimensional space map. This unmanned aerial vehicle includes fuselage and as above unmanned aerial vehicle millimeter wave radar detection system. The invention has the advantages of simple structure, low cost, active obstacle avoidance, safety, reliability, intelligent flight and the like.)

1. The millimeter wave radar detection system for the unmanned aerial vehicle is characterized by comprising a millimeter wave radar and a rotating mechanism, wherein the rotating mechanism is installed on the body of the unmanned aerial vehicle, and the millimeter wave radar is installed on the rotating mechanism and synchronously rotates along with the rotating mechanism.

2. The unmanned millimeter wave radar detection system of claim 1, wherein the rotation mechanism is a rotary pan/tilt head.

3. An unmanned aerial vehicle comprising a fuselage, further comprising the unmanned aerial vehicle millimeter wave radar detection system of claim 1 or 2.

4. A detection method based on the millimeter wave radar detection system of the unmanned aerial vehicle of claim 1 or 2, characterized by comprising the steps of:

in the flight process of the unmanned aerial vehicle, the millimeter wave radar performs rotary scanning; wherein the rotational scan path is: the front part of the machine body, the lower part of the machine body, the rear part of the machine body, or the rear part of the machine body, the lower part of the machine body and the front part of the machine body;

and (4) combining the flight state of the unmanned aerial vehicle, obtaining target information through radar rotation scanning, and constructing a flight three-dimensional space map.

5. The detection method according to claim 4, wherein after the flight three-dimensional space map is constructed, the flight attitude and speed are adjusted according to the flight three-dimensional space map to perform active obstacle avoidance.

6. The detection method according to claim 4 or 5, wherein the specific process of obtaining the target information by radar rotation scanning according to the flight state of the unmanned aerial vehicle is as follows:

the millimeter wave radar scans the transverse distance and the longitudinal height of the unmanned aerial vehicle from the target, and the spatial position of the target at the current moment is constructed;

and obtaining a flight three-dimensional space map according to the scanning result of the millimeter wave radar for multiple times.

7. The detection method according to claim 4 or 5, wherein the flight state of the unmanned aerial vehicle comprises the flight speed of the unmanned aerial vehicle, the flight attitude and the rotation angle of the rotating mechanism.

8. The detection method according to claim 4 or 5, wherein the rotational scanning path is in a range of 0 to 180 degrees from directly in front of the body to directly below the body to directly behind the body; or the range of 180-0 degrees from right behind the fuselage, right below the fuselage and right in front of the fuselage.

9. The detection method according to claim 8, wherein the elevation surface coverage angle of each scanning of the millimeter wave radar is n degrees, and 180 degrees of three-dimensional space at the lower part of the body is scanned after 180/n times of rotation.

10. The detection method according to claim 4 or 5, wherein when the millimeter wave radar rotation scanning direction is right below the body, the height of the body from an obstacle below can be detected, and unmanned aerial vehicle height setting is realized.

Technical Field

The invention mainly relates to the technical field of unmanned aerial vehicles, in particular to an unmanned aerial vehicle millimeter wave radar detection system, a detection method and an unmanned aerial vehicle.

Background

With the rapid development of science and technology, industrial unmanned aerial vehicles such as agriculture, electric power, industry, fire fighting and the like are more and more pursued by consumers. Meanwhile, more and more requirements are provided for the flight intellectualization and safety of the unmanned aerial vehicle. The existing unmanned aerial vehicle intellectualization mostly comprises intelligent detection equipment and an intelligent flight control algorithm. The intelligent detection system generally comprises an unmanned aerial vehicle obstacle avoidance scheme and an unmanned aerial vehicle height determination scheme.

The traditional unmanned aerial vehicle obstacle avoidance usually is a passive obstacle avoidance mode, namely, the unmanned aerial vehicle flyer observes the surrounding environment of the unmanned aerial vehicle through a real-time picture transmitted by an airborne camera. Meanwhile, the flyer adjusts the flight scheme in time according to the flight condition and the environment. The scheme is greatly influenced by the image transmission quality of the camera and the weather, is easily influenced by the man-made influence of a flyer and the flying control technology of the flyer, and has larger obstacle avoidance risk. As the radar is rapidly turned to the civil field from the military field, more application fields are excavated step by step, and the application of the radar to the unmanned aerial vehicle obstacle avoidance field is a new industry. It can be as an automatic autonomic obstacle avoidance scheme, also is being favored by more and more unmanned aerial vehicle manufacturers. The unmanned aerial vehicle of mainstream keeps away the barrier scheme like this installs the millimeter wave radar on the unmanned aerial vehicle fuselage, and the problem of keeping away the barrier can very well be solved to unmanned aerial vehicle. The millimeter wave radar transmits electromagnetic waves, receives echo signals and performs a series of signal processing, so that obstacle information (including real-time distance, angle, speed and the like of an obstacle) in a radar beam range can be obtained. Simultaneously, give unmanned aerial vehicle flight control system with barrier information transfer, combine unmanned aerial vehicle self flight state again, real-time autonomic judgement danger level, unmanned aerial vehicle automatically regulated flight state is in time independently kept away the barrier, has reduced the flight accident and has taken place, has improved flight efficiency. And, because outstanding environment and weather adaptability of millimeter wave radar, its under abominable weather environment, also can normal work, furthest's reduction is because the emergence of unmanned aerial vehicle crash, personal safety accident etc. that artificial error and weather influence caused.

In addition, present unmanned aerial vehicle will carry on range unit more, as the main judgement foundation of unmanned aerial vehicle flying height. Due to the excellent performance of the millimeter wave radar, the millimeter wave radar is generally applied to the unmanned aerial vehicle height-fixing scheme, and the basic working principle of the millimeter wave radar is similar to that of the millimeter wave radar of the obstacle avoidance scheme.

The system schematic diagram of the intelligent detection equipment is shown in fig. 1, and the obstacle avoidance equipment and the height fixing equipment are respectively installed on the unmanned aerial vehicle flight device and used for detecting obstacle information on a flight route of the unmanned aerial vehicle and the height of the unmanned aerial vehicle from the ground in the flight process. Through carrying out data processing in flight control system, can obtain information such as unmanned aerial vehicle place ahead barrier distance, angle, can also obtain unmanned aerial vehicle simultaneously apart from the nearest barrier height in below, but through the research discovery of this patent applicant, this scheme has following not enough:

(1) currently, according to height fixing equipment, the flight height of the unmanned aerial vehicle can be obtained in real time; according to the obstacle avoidance device, the information of the front obstacle can be obtained in real time. To a certain extent, in unmanned aerial vehicle flight control system, can judge whether unmanned aerial vehicle flies safely according to above-mentioned information to function such as obstacle is kept away in the initiative. However, the unmanned aerial vehicle flight control system can only acquire information such as obstacles and flight heights on a flight line of the unmanned aerial vehicle, and cannot intelligently sense the whole flight space environment, so that potential hidden dangers exist for flight safety.

(2) Because the height-fixed radar and the obstacle-avoidance radar are required to be installed on the body of the unmanned aerial vehicle, and multiple types of radars are adopted, the detection effect is limited, the phenomenon of mutual interference of the multiple radars is possible, and the system cost is increased. And because walk the line loaded down with trivial details, still can cause the influence to the whole waterproof function of unmanned aerial vehicle, can produce the load to unmanned aerial vehicle battery powered simultaneously.

(3) In spacious environment or the less environment of topography fluctuation, unmanned aerial vehicle flight space environment is comparatively clean, and the barrier that has the potential threat of flight is comparatively simple, and at this moment, unmanned aerial vehicle can realize initiatively keeping away the barrier, function such as obstacle-detouring even. However, in the environments of steep slopes, undulating mountainous regions and the like, the scheme can only detect the obstacle information on the flight route, cannot judge the obstacle profile in a three-dimensional manner, can only carry out active braking, and cannot adjust the flight attitude, the speed and the like according to the overall space profile of the obstacle, so that the flight efficiency is reduced, and the flight intellectualization cannot be really realized.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the technical problems in the prior art, the invention provides the millimeter wave radar detection system and the detection method for the unmanned aerial vehicle and the unmanned aerial vehicle, which have the advantages of simple structure, low cost, active obstacle avoidance, safety and reliability.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

the millimeter wave radar detection system for the unmanned aerial vehicle comprises a millimeter wave radar and a rotating mechanism, wherein the rotating mechanism is installed on the body of the unmanned aerial vehicle, and the millimeter wave radar is installed on the rotating mechanism and synchronously rotates along with the rotating mechanism.

As a further improvement of the above technical solution:

the rotating mechanism is a rotating holder.

The invention also discloses an unmanned aerial vehicle which comprises a vehicle body and the unmanned aerial vehicle millimeter wave radar detection system.

The invention further discloses a detection method based on the unmanned aerial vehicle millimeter wave radar detection system, which comprises the following steps:

in the flight process of the unmanned aerial vehicle, the millimeter wave radar performs rotary scanning; wherein the rotational scan path is: the front part of the machine body, the lower part of the machine body, the rear part of the machine body, or the rear part of the machine body, the lower part of the machine body and the front part of the machine body;

and (4) combining the flight state of the unmanned aerial vehicle, obtaining target information through radar rotation scanning, and constructing a flight three-dimensional space map.

As a further improvement of the above technical solution:

after the flight three-dimensional space map is constructed, the flight attitude and the flight speed are adjusted according to the flight three-dimensional space map so as to actively avoid the obstacle.

According to the flight state of the unmanned aerial vehicle, the specific process of obtaining target information by radar rotation scanning is as follows:

the millimeter wave radar scans the transverse distance and the longitudinal height of the unmanned aerial vehicle from the target, and the spatial position of the target at the current moment is constructed;

and obtaining a flight three-dimensional space map according to the scanning result of the millimeter wave radar for multiple times.

The flight state of the unmanned aerial vehicle comprises the flight speed of the unmanned aerial vehicle, the flight attitude and the rotation angle of the rotating mechanism.

The rotary scanning path is in the range of 0-180 degrees from the right front of the machine body, the right lower part of the machine body and the right rear of the machine body; or the range of 180-0 degrees from right behind the fuselage, right below the fuselage and right in front of the fuselage.

The pitch surface coverage angle of each scanning of the millimeter wave radar is n degrees, and 180-degree three-dimensional space at the lower part of the machine body is scanned after 180/n times of rotation.

When the rotatory scanning direction of millimeter wave radar is under the fuselage, detectable fuselage realizes that unmanned aerial vehicle decides the height from the height of below barrier.

Compared with the prior art, the invention has the advantages that:

the millimeter wave radar is controlled by the rotating mechanism (such as a rotatable holder) to realize 180-degree segmented full scanning, and each detection only aims at the three-dimensional space faced by the current rotating angle, so that the whole three-dimensional space is covered by multiple times of rotation; the whole three-dimensional space is reconstructed at each position of the three-dimensional space in real time through the known rotation angle and the detection information corresponding to the existing scanning angle, so that dead-angle-free coverage of the flying three-dimensional space environment is realized, flying threats are predicted in time, the flying state is adjusted according to the environment, and the functions of avoiding obstacles, avoiding obstacles and the like are realized autonomously. The invention is suitable for the zones with large fluctuation of flying environment, limited flying space and irregular flying obstacles, and the flying state is adjusted in time through the flying three-dimensional space map constructed by the millimeter wave radar so as to ensure the flying safety to the maximum extent by the flight intellectualization; the whole detection system only needs to be configured with one radar, so that the cost is low, and the interference among a plurality of different radars can be avoided. The invention adopts a millimeter wave radar with a wide horizontal angle and a narrow pitching angle; because the horizontal visual angle is wider, the threatening target can be detected in time; the pitching visual angle is more accurate, and the false alarm condition caused by overlarge visual angle can be avoided.

Drawings

Fig. 1 is a schematic system diagram of an intelligent detection device for an unmanned aerial vehicle in the prior art.

Fig. 2 is a schematic view of a detection field angle of a current millimeter wave radar.

FIG. 3 is a block schematic diagram of a system of the present invention in an embodiment.

Fig. 4 is a schematic view of the operation principle of the millimeter wave radar of the present invention.

Fig. 5 is a schematic perspective view of the radar of the present invention.

FIG. 6 is a schematic diagram of a typical slope detection in the present invention.

Detailed Description

The invention is further described below with reference to the figures and the specific embodiments of the description.

As shown in fig. 3, the millimeter wave radar detection system of the unmanned aerial vehicle of the embodiment includes a millimeter wave radar and a rotating mechanism, the rotating mechanism is installed on the body of the unmanned aerial vehicle, and the millimeter wave radar is installed on the rotating mechanism and rotates and scans along with the synchronous rotation of the rotating mechanism. Specifically, the rotating mechanism can adopt a conventional structure such as a rotating mechanism or a steering engine; the millimeter wave radar can adopt a millimeter wave radar with a large horizontal angle and a small pitching angle, and the detection field angle of the millimeter wave radar is shown in fig. 2, wherein L represents the horizontal field angle width of the radar, and H represents the pitching field angle width of the radar. The wide horizontal field angle can detect more targets of the radar transverse cross section, predict threats in time and restore the outer contour of the obstacle to the maximum extent; the narrow pitching angle of view, the space solid area that covers in every detection is little, avoids some to be in radar every single move visual angle scope but its obstacle that fails to reach unmanned aerial vehicle altitude again to the influence of unmanned aerial vehicle flight.

As shown in fig. 3, in this embodiment, the rotating platform swings at a certain speed by 0-180 degrees (where 0 degree is a direction directly ahead of the flight of the drone, 90 degrees is a direction directly below the fuselage of the drone, and 180 degrees is a direction directly behind the flight of the drone, as shown in fig. 5). The detection range of the millimeter wave radar is synchronously changed along with the mechanical rotation of the rotating holder. The detection range of the millimeter wave radar is driven by each rotation of the rotating holder to change, so that target information of 0-180 degrees on a flight route of the unmanned aerial vehicle is obtained, wherein obstacle information on the flight route of the unmanned aerial vehicle can be obtained at 0 degree and 180 degrees, and when the holder is at 90 degrees, flight height information of the unmanned aerial vehicle can be obtained to realize unmanned aerial vehicle height fixing.

The specific working process is as follows: the method comprises the following steps that the radar and a flight control system are in two-way communication, the flight control system periodically transmits information of the flight state (such as flight speed, rotation angle of a holder, flight attitude and the like) of the unmanned aerial vehicle to a millimeter wave radar, and the millimeter wave radar virtually constructs a flight three-dimensional space map according to detected target information; and simultaneously reporting all scanned target information to a flight control system, and intelligently judging the surrounding environment of the unmanned aerial vehicle flying according to the uploaded target information by the flight control system. The flight control system judges the potential threat situation of the flight safety of the unmanned aerial vehicle according to the three-dimensional map information established by the radar, adjusts the flight attitude and speed in time, and controls the unmanned aerial vehicle flight device to realize the functions of autonomous obstacle avoidance, obstacle detouring and the like.

The working principle of the millimeter wave radar is shown in fig. 4: the millimeter wave radar transmits electromagnetic wave signals, the electromagnetic wave signals are reflected by the obstacle and then received by the radar, and difference frequency signals are obtained after the millimeter wave radar passes through the frequency mixer; and (3) carrying out signal processing on the difference frequency signal in a signal processor, wherein the signal processing comprises Fast Fourier Transform (FFT), constant false alarm rate detection (CFAR), direction of arrival estimation (DOA), false alarm management, track management and the like, so that information such as the distance, the speed, the angle and the like of a target is obtained, then the target information is integrated, and finally the target information is output to a flight control system.

The millimeter wave radar is controlled by the rotatable holder to realize 180-degree segmented full scanning, and each detection only aims at the three-dimensional space faced by the current rotation angle, so that the whole three-dimensional space is covered by rotating for multiple times; the whole three-dimensional space is reconstructed at each position of the three-dimensional space in real time through the known rotation angle and the detection information corresponding to the existing scanning angle, so that dead-angle-free coverage of the flying three-dimensional space environment is realized, flying threats are predicted in time, the flying state is adjusted according to the environment, and the functions of avoiding obstacles, avoiding obstacles and the like are realized autonomously.

The invention also discloses a detection method based on the unmanned aerial vehicle millimeter wave radar detection system, which comprises the following steps:

in the flight process of the unmanned aerial vehicle, the millimeter wave radar performs rotary scanning; wherein the rotational scan path is: the front part of the machine body, the lower part of the machine body, the rear part of the machine body, or the rear part of the machine body, the lower part of the machine body and the front part of the machine body;

combining the flight state of the unmanned aerial vehicle, obtaining target information through radar rotation scanning, and constructing a flight three-dimensional space map;

after the flight three-dimensional space map is constructed, the flight attitude and the flight speed are adjusted according to the flight three-dimensional space map so as to actively avoid the obstacle.

As shown in fig. 5, the radar stereo scanning process based on the rotating pan/tilt head is as follows: the rotating holder rotates at a certain speed, the coverage angle of the pitching surface of the radar is 5 degrees, and under the condition that the detection ranges of the radar are not overlapped each time, 180-degree three-dimensional space can be scanned through 36 times of rotation. After scanning the space of 0-180 degrees, the cradle head rotates reversely, and covers the space of 180-0 degrees again, and so on, thereby achieving the uninterrupted operation of the radar scanning space. The rotating speed of the rotating holder can be configured automatically, if the rotating speed is too fast, adjacent detection pitching coverage areas of the radar can be overlapped, and accurate information of the target can be further obtained through multiple overlapping detection judgment. Take 36 rotations covering 180 degrees of space with a radar refresh rate of 36Hz (i.e. 36 detectable by the radar for 1 second) as an example. In 1 second, the radar can cover the whole three-dimensional 180-degree space along with the rotation of the holder. Wherein when the cloud platform rotated 90 degrees, the radar can detect unmanned aerial vehicle from the height of below barrier, realized unmanned aerial vehicle's height surely. Of course, in other embodiments, different refresh rates may be selected or other angles of pitch surface coverage per time.

When the unmanned aerial vehicle is lifted off, the rotating holder is started, and the rotating holder rotates to drive the radar to rapidly scan the whole flying three-dimensional space. Each scanning detection is independent, and in one scanning period, the three-dimensional space map of the flying environment can be obtained by accumulating and processing the detection results for multiple times. And (3) taking the position in the direction of 0 degree as a starting point, feeding all scanned data of the scanning (0 degree- >180 degree- >0 degree) back to the current scanning position, and finally forming a flight motion three-dimensional space diagram.

Taking a flying sloping field environment as an example, the flying front of the unmanned aerial vehicle is an upward slope, and the lower part of the unmanned aerial vehicle is the ground. A typical slope detection diagram is shown in fig. 6:

the flying speed of the unmanned aerial vehicle is V, and the tripod head scans to 180 degrees from 0 degree, and N (N is 36) scanning periods are counted. The initial position of A point for unmanned aerial vehicle initial moment (when the cloud platform is in 0 degree direction of flight direction, the dead ahead promptly), the radar detects the place ahead sloping and is R1 from unmanned aerial vehicle's lateral distance, and the longitudinal distance of target and unmanned aerial vehicle is 0. After n1(n1 is not more than 36) scanning periods, the tripod head rotates to a certain alpha angle direction, the unmanned aerial vehicle is located at the B point position, the radar detects that the slant distance between the front slope and the unmanned aerial vehicle is R2, and the horizontal transverse flight distance of the unmanned aerial vehicle is as follows:

R3＝n1/N*V(1)

from the calculation, the longitudinal height H1 of the target from the drone and the transverse distance R4 of the drone from the target in the B point position are scanned as follows:

wherein alpha is the angle of rotation of the holder from the point A to the point B;

at this time, a space perspective of the target of two scans can be modeled, and the space coordinates of the position of the B point of the target of two scans are respectively (R1-R3, 0), (R4, H1). After n2(n2 is not more than 36) scanning periods, the unmanned aerial vehicle is located at the position of the C point, the holder rotates to the angle direction of beta, and the distance from the front slope to the unmanned aerial vehicle, which is detected by the radar, is R5 in an oblique direction. According to the above calculation, the transverse flight distance of the unmanned aerial vehicle is: r6 ═ N2/N × V. The longitudinal height of the target from the unmanned aerial vehicle and the transverse distance of the unmanned aerial vehicle from the target are respectively scanned at the position of the C point:

by the same reasoning, the three detected space coordinates of the target at the position of the C point are respectively (R1-R3-R6, 0), (R4-R6, H1), (R7 and H2).

From the above, at each scanning time in the flight process, the spatial position of the scanned target at the current time can be constructed according to the data of the known scanning. By analogy, through a complete scanning period, the space coordinates of all targets at 0-180 degrees can be modeled, and thus the three-dimensional space diagram of the flight environment of the unmanned aerial vehicle can be obtained. At each moment, the radar can construct a space target information stereogram and upload the information to the flight control system, and the flight control system intelligently judges the surrounding environment conditions of the flight according to the space target information chart reported by the radar, timely adjusts the flight scheme and autonomously realizes obstacle avoidance and obstacle detouring flight.

According to the millimeter wave radar detection system and method for the unmanned aerial vehicle, the radar is controlled to do regular circular motion through the rotating holder, the whole three-dimensional detection space is decomposed into a plurality of small-view-angle spaces for detection, and therefore detection of the whole space is achieved; through detection decomposition and conversion of different scanning angles for many times, the three-dimensional space coordinates of all detected targets can be obtained at any time, so that a flying three-dimensional space map can be constructed, the flying state of the unmanned aerial vehicle can be adjusted in real time, and the functions of obstacle avoidance, obstacle avoidance and the like are achieved.

The invention is suitable for the zones with large fluctuation of flying environment, limited flying space and irregular flying obstacles, and the flying state is timely adjusted through the three-dimensional space scanning diagram constructed by the millimeter wave radar so as to ensure the flying safety to the maximum extent by the flight intellectualization.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.