CN108803666A - A kind of line data-logging unmanned plane barrier-avoiding method and system based on millimetre-wave radar - Google Patents

Abstract

The invention discloses an obstacle avoidance method and system for a line inspection UAV based on a millimeter-wave radar. The method includes the following steps: transmitting a radar signal through the millimeter-wave radar, judging whether a radar echo signal is received, and if If no, it is judged that there is no obstacle; if yes, a level warning signal is output according to the radar echo signal; the UAV adjusts the flight state according to the warning signal. The millimeter-wave radar-based rotor UAV line inspection and obstacle avoidance method and system provided by the present invention, by setting the millimeter-wave radar on the UAV and setting the level alarm signal, the recognition accuracy of the millimeter-wave radar can reach the wire level, overcoming The problem of insufficient identification accuracy of the existing obstacle detection method using sensors is realized. Through real-time detection of obstacles in different directions between the UAV and the surroundings, different degrees of danger alarms are issued, and the flight speed and direction are automatically adjusted to realize UAV obstacle avoidance. , effectively avoiding the accident of the UAV colliding with the wire.

Description

An obstacle avoidance method and system for a line inspection UAV based on millimeter wave radar

technical field

The invention relates to the field of unmanned aerial vehicles, in particular to an obstacle avoidance method for a line inspection unmanned aerial vehicle based on millimeter wave radar.

Background technique

As a new type of line inspection equipment, unmanned aerial vehicles have the advantages of convenient portability, unaffected operation by region, and high work efficiency, and have been widely used in the field of power grids. On the UAV body, equipped with visible light, infrared thermal imager and oblique photography device, it can inspect and detect the transmission line from a long distance, from multiple angles, and flexibly, but it is limited by the visual distance of the operator and the Operational precision is prone to accidents where drones collide with wires. Therefore, UAV obstacle avoidance technology is particularly important in the process of line inspection.

In the existing UAV obstacle avoidance technology, sensors are often used to detect obstacles. For example, "A Multi-rotor UAV Autonomous Obstacle Avoidance Device and Obstacle Avoidance Method" (CN201810115267.3) uses a rotating detection sensor, Realize the detection of obstacles in the flight direction of the UAV, and then control the flight speed and direction; and "A UAV Obstacle Avoidance System for Transmission Line Inspection" (CN201711259999.1) through millimeter-wave radar and ultrasonic sensors Real-time measurement and control of obstacles with visual sensors, and then automatically adjust according to the distance between the UAV and obstacles. However, the sensor-based obstacle detection method has the problem of low sensor recognition accuracy, which is not enough to distinguish the wires; the obstacle recognition method based on the joint measurement and control of millimeter-wave radar and sensors increases the load of the UAV, resulting in the flexibility of the UAV. Insufficient and costly.

Contents of the invention

In order to solve the problems raised in the above-mentioned background technology, the present invention provides an obstacle avoidance method and system for a line inspection UAV based on a millimeter wave radar. By setting a level of early warning, the UAV is prompted to adjust the flight state, and the UAV can be flexibly avoided. barrier.

The first part of the present invention provides a method for avoiding obstacles of a line inspection drone based on millimeter wave radar, including the following steps:

The radar signal is transmitted by the millimeter-wave radar, and it is judged whether the radar echo signal is received, and if not, it is judged that there is no obstacle; if so, the level warning signal is output according to the radar echo signal; Adjust the flight status according to the above warning signal.

As an optional solution, the outputting level warning signal according to the radar echo signal is specifically: obtaining the distance R between the UAV and the obstacle according to the radar echo signal; The ratio r of the distance outputs the corresponding level alarm signal.

As an optional solution, the corresponding level alarm signal output according to the ratio of the distance R to the preset safety distance is specifically: if r>1.2, then no alarm signal; if 1.2≥r>1.1, then output yellow Alarm signal; if 1.1≥r>1, an orange alarm signal will be output; if r≤1, a red alarm signal will be output.

As an alternative, the relationship between the preset safety distance and the voltage of the AC transmission line includes: when the voltage is 110kV, the preset safety distance is 3m; when the voltage is 220kV, the preset safety distance is 5m; when the voltage When the voltage is 330kV, the preset safety distance is 7m; when the voltage is 500kV, the preset safety distance is 10m; when the voltage is 750kV, the preset safety distance is 12m; when the voltage is 1000kV, the preset safety distance is 15m.

As an optional solution, the relationship between the preset safety distance and the voltage of the DC transmission line includes: when the voltage is ±500kV, the preset safety distance is 15m; when the voltage is ±660kV, the preset safety distance is 18m; When the voltage is ±800kV, the preset safety distance is 20m.

As an optional solution, the UAV is provided with millimeter-wave radars in four directions: forward, backward, left, and right, and the output level warning signal according to the radar echo signal specifically includes: According to the forward, backward, left and right radar echo signals, the level warning signal of the corresponding direction is obtained.

As an optional solution, the UAV adjusts the flight state according to the warning signal as follows:

A. If there is only one direction to output the alarm signal, slow down the flight speed of the alarm direction. If the alarm level is red, then move in parallel to the opposite direction of the alarm direction; B. If two opposite directions output alarm signals, the direction of the alarm level is smaller Move in parallel in the same direction until the high-level warning is lowered. If the warning level is the same and is not red, then move in parallel in the direction with a larger distance; if the warning levels are all red, return along the original flight path; C. If If the warning signals are output in three directions or four directions, the flight status is adjusted according to the above-mentioned A or B respectively.

As an optional solution, the radar signal is a frequency-modulated continuous wave, and the distance R is obtained through a frequency difference between the radar signal and the radar echo signal.

The second part of the present invention provides a line inspection UAV obstacle avoidance system based on millimeter wave radar. The UAV obstacle avoidance system includes a millimeter wave radar, an alarm level module and a flight adjustment module; the millimeter wave radar is used for The radar signal is transmitted and the radar echo signal is received; the warning level module is used to output a level warning signal according to the radar echo signal; the flight adjustment module is used to adjust the flight state according to the warning signal.

As an optional solution, the UAV is provided with millimeter-wave radars in four directions: forward, backward, left, and right, and the flight adjustment module is used to adjust the flight state according to the warning signal. :

A. If there is only one direction to output the alarm signal, slow down the flight speed of the alarm direction. If the alarm level is red, then move in parallel to the opposite direction of the alarm direction; B. If two opposite directions output alarm signals, the direction of the alarm level is smaller Move in parallel in the same direction until the high-level warning is lowered. If the warning level is the same and not the highest level, move in parallel in the direction with a larger distance; if the warning level is the highest level, return along the original flight path; C . If warning signals are output in three directions or four directions, then adjust the flight status according to the above A or B respectively.

The advantage of the present invention is that: the millimeter-wave radar-based rotor UAV line inspection and obstacle avoidance method and system provided by the present invention, by setting the millimeter-wave radar on the UAV, and setting the level alarm signal, the recognition accuracy of the millimeter-wave radar It can reach the wire level, which overcomes the problem of insufficient recognition accuracy of the existing sensor-based obstacle detection method. Through real-time detection of obstacles in different directions between the UAV and the surroundings, different degrees of danger alarms are issued, and the flight speed and direction are automatically adjusted. Realize UAV obstacle avoidance, effectively avoid the accident of UAV colliding with wire.

Description of drawings

Fig. 1 is a schematic flow chart of the obstacle avoidance method for the line inspection drone based on the millimeter wave radar provided by the embodiment of the present invention;

FIG. 2 is a schematic diagram of the principle of radar ranging based on frequency modulated continuous waves provided by an embodiment of the present invention;

Fig. 3 is the layout diagram of the UAV nose radar array provided by the embodiment of the present invention;

Fig. 4 is a schematic diagram of different levels of warnings for drone inspection flights provided by an embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and in combination with specific embodiments.

Embodiment one

As shown in Figure 1, the schematic flow chart of the obstacle avoidance method for the line inspection drone based on the millimeter-wave radar provided by the embodiment of the present invention, the method provided by the embodiment of the present invention includes the following steps:

The radar signal is transmitted by the millimeter-wave radar, and it is judged whether the radar echo signal is received, and if not, it is judged that there is no obstacle; if so, the level warning signal is output according to the radar echo signal; Adjust the flight status according to the above warning signal.

That is, by transmitting and receiving radar signals to judge the presence or absence of obstacles and measure the distance between the UAV and obstacles. If there is no radar echo signal after transmitting the radar signal, that is, the received radar signal is 0, it is judged that there is no obstacle or the distance between the obstacle and the UAV is too large.

In this embodiment, by setting the millimeter-wave radar on the UAV and setting the level alarm signal, the recognition accuracy of the millimeter-wave radar can reach the wire level, which overcomes the problem of insufficient recognition accuracy of the existing obstacle detection method using sensors. Through real-time detection The UAV and the obstacles in different directions around it will give different degrees of danger warning, and automatically adjust the flight speed and direction to realize the UAV obstacle avoidance, effectively avoiding the accident of the UAV colliding with the wire.

Optionally, as shown in FIG. 2 , the radar signal is a frequency-modulated continuous wave, and the distance R is obtained through a frequency difference between the radar signal and the radar echo signal.

Optionally, the outputting level warning signal according to the radar echo signal is specifically: obtaining the distance R between the UAV and the obstacle according to the radar echo signal; according to the ratio of the distance R to the preset safety distance r output corresponding level alarm signal.

The millimeter-wave radar used in this embodiment has a frequency of 77 GHz and a wavelength of 3.9 mm, which can identify wire-level obstacles. If f ₀ is the frequency difference between the radar transmitted signal and the reflected signal, T is the period of the modulated triangular wave, and △F is the frequency modulation bandwidth, then R can be expressed as

In the formula, c is the electromagnetic wave velocity, that is, c=3×108m/s.

Optionally, as shown in FIG. 3 , the corresponding level alarm signal output according to the ratio of the distance R to the preset safety distance is specifically: if r>1.2, no alarm signal; if 1.2≥r>1.1, Then output a yellow alarm signal; if 1.1≥r>1, then output an orange alarm signal; if r≤1, then output a red alarm signal.

The specific alarm level classification is shown in Table 1.

Table 1 Classification of drone inspection safety flight warning levels

r r≥1.2 1.1<r≤1.2 1<r≤1.1 r≤1 Alarm level no warning yellow orange red

Optionally, the UAV is equipped with millimeter-wave radars in the four directions of forward, backward, left, and right, and the outputting a level alarm signal according to the radar echo signal specifically includes: , backward, left, and right radar echo signals to obtain level warning signals in the corresponding direction.

Optionally, the relationship between the preset safety distance and the voltage of the AC transmission line includes: when the voltage is 110kV, the preset safety distance is 3m; when the voltage is 220kV, the preset safety distance is 5m; when the voltage is 330kV , the preset safety distance is 7m; when the voltage is 500kV, the preset safety distance is 10m; when the voltage is 750kV, the preset safety distance is 12m; when the voltage is 1000kV, the preset safety distance is 15m.

Optionally, the relationship between the preset safety distance and the voltage of the direct current transmission line includes: when the voltage is ±500kV, the preset safety distance is 15m; when the voltage is ±660kV, the preset safety distance is 18m; when the voltage is When ±800kV, the preset safety distance is 20m.

As shown in Figure 4, the UAV is equipped with four millimeter-wave radars in the four directions of forward, backward, left, and right, which can respectively obtain The shortest distance of the obstacle, and compare it with the preset safety distance; the transmission line is divided into AC and DC, and the preset safety distance of the voltage level transmission line is shown in the table below

Table 2 Preset safe distance for UAV inspection of AC transmission lines

Voltage level 110kV 220kV 330kV 500kV 750kV 1000kV Preset safety distance (m) 3 5 7 10 12 15

Table 3 Preset safe distance for UAV inspection of DC transmission lines

Voltage level ±500kV ±660kV ±800kV Preset safe flight distance (m) 15 18 20

Optionally, the UAV adjusts the flight state according to the warning signal as follows: A. If there is only one direction to output the warning signal, then slow down the flight speed in the warning direction; if the warning level is red, then move in the direction opposite to the warning direction Parallel movement; B. If the alarm signals are output in two opposite directions, then move in parallel in the direction of the smaller alarm level until the high level alarm is reduced. If the alarm level is the same and it is not red, then move in parallel in the direction of the larger distance ; If the warning levels are all red, return along the original flight track; C. If the warning signals are output in three directions or four directions, then adjust the flight status according to the above-mentioned A or B respectively.

According to different directions and different levels of warning conditions, the flight speed and direction are automatically adjusted to avoid obstacles. The specific performance is: when an alarm occurs in a certain direction, the flying speed of the drone in the current direction should be slowed down. If the alarm level reaches red, it should move in parallel in the opposite direction until the red alarm decreases.

When there are alarms in the two opposite directions of front, rear or left and right, move in parallel in the direction of the smaller alarm level until the high level alarm is reduced. If the alarm level is the same and it is not red, move in parallel in the direction with the shortest distance Move until the shortest distance in these two directions is basically the same; if the alarm levels are all red, return along the original flight path until the red alarm is lowered.

When an alarm occurs in three directions or four directions, it is divided into two steps: front and rear direction adjustment and left and right direction adjustment. According to the above-mentioned single direction or two direction alarm processing method, the UAV flight speed and Orientation adjustment.

Measure the distance between the UAV and the surrounding obstacles through the millimeter-wave radar arranged in the four directions of front, rear, left and right, compare the shortest distance in different directions with the preset safe flight distance, and emit a yellow signal according to the ratio , Orange, and Red three levels of danger alarms, and finally according to different directions and different levels of alarms, automatically adjust the flight speed and direction to realize the UAV obstacle avoidance.

The millimeter-wave radar-based line inspection UAV obstacle avoidance method provided in this embodiment can accurately identify wire-level obstacles, and can measure the distance between the UAV and the obstacle in the four directions of front, back, left, and right. Carry out different levels of danger alarms, and then automatically adjust the flight status of the UAV to achieve obstacle avoidance, which is safe and reliable, and has strong practicability.

Embodiment two

The second part of the present invention provides a line inspection UAV obstacle avoidance system based on millimeter wave radar. The UAV obstacle avoidance system includes a millimeter wave radar, an alarm level module and a flight adjustment module; the millimeter wave radar is used for The radar signal is transmitted and the radar echo signal is received; the warning level module is used to output a level warning signal according to the radar echo signal; the flight adjustment module is used to adjust the flight state according to the warning signal.

As an optional solution, the UAV is provided with millimeter-wave radars in four directions: forward, backward, left, and right, and the flight adjustment module is used to adjust the flight state according to the warning signal. :

A. If there is only one direction to output the alarm signal, slow down the flight speed of the alarm direction. If the alarm level is red, then move in parallel to the opposite direction of the alarm direction; B. If two opposite directions output alarm signals, the direction of the alarm level is smaller Move in parallel in the same direction until the high-level warning is lowered. If the warning level is the same and not the highest level, move in parallel in the direction with a larger distance; if the warning level is the highest level, return along the original flight path; C . If warning signals are output in three directions or four directions, then adjust the flight status according to the above A or B respectively.

For the specific workflow and working principle of the millimeter-wave radar-based line inspection UAV obstacle avoidance system provided in this embodiment, please refer to Embodiment 1, and details will not be repeated here.

Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowcharts and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each procedure and/or block in the flowchart and/or block diagram, and a combination of procedures and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions may be provided to a general purpose computer, special purpose computer, embedded processor, or processor of other programmable data processing equipment to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing equipment produce a An apparatus for realizing the functions specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions The device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

These computer program instructions can also be loaded onto a computer or other programmable data processing device, causing a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process, thereby The instructions provide steps for implementing the functions specified in the flow chart or blocks of the flowchart and/or the block or blocks of the block diagrams.

The above are only embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the pending application of the present invention. within the scope of the claims.

Claims (10)

1. a kind of line data-logging unmanned plane barrier-avoiding method based on millimetre-wave radar, which is characterized in that include the following steps：

Emit radar signal by the millimetre-wave radar,

Judge whether to receive radar echo signal, if it is not, then judging clear；If so, being believed according to the radar return Number output level alarm signal；

The unmanned plane adjusts state of flight according to the alarm signal.

2. the line data-logging unmanned plane barrier-avoiding method according to claim 1 based on millimetre-wave radar, which is characterized in that institute It states and is specially according to the radar echo signal output level alarm signal：

Unmanned plane and barrier distance R are obtained according to the radar echo signal；

According to distance R grade alarm signals corresponding with the output of the ratio r of default safe distance.

3. the line data-logging unmanned plane barrier-avoiding method according to claim 2 based on millimetre-wave radar, which is characterized in that institute It states and is specially according to distance R grade alarm signals corresponding with the output of the ratio of default safe distance：

If r > 1.2, no alarm signal；

If 1.2 >=r > 1.1 export yellow alarm signal；

If 1.1 >=r > 1 export orange alarm signal；

If r≤1, output red alarm signal.

4. the line data-logging unmanned plane barrier-avoiding method according to claim 3 based on millimetre-wave radar, which is characterized in that institute The voltage relationship for stating default safe distance and transmission line of alternation current includes：

When voltage is 110kV, default safe distance 3m；

When voltage is 220kV, default safe distance 5m；

When voltage is 330kV, default safe distance 7m；

When voltage is 500kV, default safe distance 10m；

When voltage is 750kV, default safe distance 12m；

When voltage is 1000kV, default safe distance 15m.

5. the line data-logging unmanned plane barrier-avoiding method according to claim 3 based on millimetre-wave radar, which is characterized in that institute The voltage relationship for stating default safe distance and DC power transmission line includes：

When voltage is ± 500kV, default safe distance 15m；

When voltage is ± 660kV, default safe distance 18m；

When voltage is ± 800kV, default safe distance 20m.

6. special according to line data-logging unmanned plane barrier-avoiding method of claim 2 to 5 any one of them based on millimetre-wave radar Sign is that the unmanned plane is equipped with millimetre-wave radar in forward, backward, left-hand, dextrad four direction, described according to the radar Echo-signal output level alarm signal specifically includes：

The grade alarm signal of corresponding direction is obtained according to the radar echo signal of forward, backward, left-hand, dextrad respectively.

7. special according to line data-logging unmanned plane barrier-avoiding method of the claim 2-5 any one of them based on millimetre-wave radar Sign is that the unmanned plane adjusts state of flight according to the alarm signal and is specially：

If A. only there are one direction outputting alarm signals, slow down the flying speed in alarm direction, if alarm grade is red, It is moved in parallel towards alarm direction opposite direction；

If B. two opposite direction outputting alarm signals, direction towards alarm smaller grade moves in parallel, until high-grade announcement Until alert reduction, if alarm grade is identical and is not red, moved in parallel towards apart from larger direction；If alarm grade is Red is then returned along original flight track；

If the C. outputting alarm signal of three directions or four direction, state of flight is adjusted according to above-mentioned A or B respectively.

8. special according to line data-logging unmanned plane barrier-avoiding method of claim 2 to 5 any one of them based on millimetre-wave radar Sign is that the radar signal is CW with frequency modulation, and the distance R passes through the frequency between radar signal and radar echo signal Difference obtains.

9. a kind of line data-logging unmanned plane obstacle avoidance system based on millimetre-wave radar, which is characterized in that unmanned plane avoidance system System includes millimetre-wave radar, alerts grade module and flight adjustment module；

The millimetre-wave radar receives radar echo signal for emitting radar signal；

The alarm grade module is used for according to the radar echo signal output level alarm signal；

The flight adjustment module is used to adjust state of flight according to the alarm signal.

10. the line data-logging unmanned plane obstacle avoidance system according to claim 9 based on millimetre-wave radar, the unmanned plane exist Forward, backward, left-hand, dextrad four direction are equipped with millimetre-wave radar, and the flight adjustment module is used to be believed according to the alarm Number adjustment state of flight be specially：

If A. only there are one direction outputting alarm signals, slow down the flying speed in alarm direction, if alarm grade is red, It is moved in parallel towards alarm direction opposite direction；

If B. two opposite direction outputting alarm signals, direction towards alarm smaller grade moves in parallel, until high-grade announcement Until alert reduction, if alarm grade is identical and is not the superlative degree, moved in parallel towards apart from larger direction；If it is equal to alert grade For the superlative degree, then returned along original flight track；

If the C. outputting alarm signal of three directions or four direction, state of flight is adjusted according to above-mentioned A or B respectively.