CN105911561A - Unmanned aerial vehicle obstacle avoiding device and method based on laser radar - Google Patents

Abstract

A laser radar-based UAV obstacle avoidance device and obstacle avoidance method, the device includes an encoder fixed under the motor of the UAV; a laser drive circuit, a laser connected to the laser drive circuit, and a laser connected to the light output end of the laser The first reflection device, the laser beam emitted by the laser just passes through the through hole at the center point of the first reflection device, and is fixed on the second reflection device on the direct optical path of the through hole and is fixedly connected with the bottom end of the rotating shaft of the motor. The device simultaneously reflects the laser light reflected by the second reflecting device, is fixed on the converging lens on the reflected light path of the first reflecting device, and is fixed on the laser detector on the converging optical path of the converging lens; the laser distance measuring device connected with the laser detector; also includes A system processor unit connected with an encoder, a laser drive circuit and a laser ranging device; the invention also discloses an obstacle avoidance method for the device; the invention realizes 360° detection and is low in cost and small in size, and can greatly improve The ability of UAVs to avoid obstacles in complex environments.

Description

A laser radar-based UAV obstacle avoidance device and obstacle avoidance method

technical field

The invention relates to the field of aviation science, in particular to a laser radar-based unmanned aerial vehicle obstacle avoidance device and an obstacle avoidance method.

Background technique

In recent years, multi-axis UAVs have achieved rapid development, but UAVs may encounter obstacles at any time during automatic patrol flight. At present, it is mainly to use ultrasonic or visual technology to achieve obstacle avoidance. Ultrasound is the simplest ranging system, and there will be obvious interference problems in the UAV obstacle avoidance system. Secondly, if the ability of the object to reflect ultrasonic waves is insufficient, the effective distance of obstacle avoidance will be reduced, and the safety hazard is high. Vision technology is easily affected by factors such as light, dust, and smoke, and cannot meet the needs of all-weather flight.

In the traditional solution for UAVs to avoid obstacles, one method for radar to perform 360° detection is to realize 360° scanning by itself, and the other method is to use phased array radar. These two solutions require the addition of complex motor equipment As a result, additional load is generated, but the UAV should not be overloaded due to battery life and other reasons.

Therefore, it is necessary to design a light-weight 360° scanning radar device for UAV obstacle avoidance.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a laser radar-based UAV obstacle avoidance device and obstacle avoidance method. Obstacle avoidance ability in complex environment.

To achieve the above object, the present invention adopts the following technical solutions:

A kind of unmanned aerial vehicle obstacle avoidance device based on laser radar, comprises the encoder 7 that is fixed under the motor 1 of unmanned aerial vehicle and is connected with the motor 1 coaxially to measure the motor rotation angle; Also comprises laser drive circuit 8, and laser drive The laser 9 connected to the circuit 8 is fixed on the first reflector 13 at the light output end of the laser 9. The laser beam emitted by the laser 9 just passes through the through hole 10 at the center point of the first reflector 13 and is fixed on the through hole 10 on the direct light path. And the second reflection device 11 that is fixedly connected with the bottom end of the rotating shaft 6 of the motor 1, the first reflection device 13 reflects the laser light reflected back by the second reflection device 11 at the same time, and is fixed on the converging lens 14 on the reflection optical path of the first reflection device 13, A laser detector 15 fixed on the converging optical path of the converging lens 14; a laser distance measuring device 16 connected to the laser detector 15; also includes a system process connected with the encoder 7, the laser drive circuit 8 and the laser distance measuring device 16 device unit 17.

The second reflection device 11 is fixed on the bottom end of the motor shaft and rotates simultaneously with the motor, and the second reflection device 11 forms an included angle of 45 degrees with the horizontal direction.

The first reflecting device 13 forms an included angle of 45 degrees with the horizontal direction.

The laser detector 15 receives the laser light converged by the convergent lens 14 for subsequent processing by the laser ranging device 16 .

The laser driving device 8 , laser 9 , second reflecting device 11 , first reflecting device 13 , converging lens 14 , laser detector 15 and laser ranging device 16 are packaged inside a lidar housing 18 .

The obstacle avoidance method of the above-mentioned laser radar-based unmanned aerial vehicle obstacle avoidance device comprises the steps:

Step 1, when the motor 1 rotates, the encoder 7 and the second reflection device 11 fixed on the rotating shaft 6 are driven to rotate simultaneously;

Step 2, the laser drive circuit 8 drives the laser 9 to emit laser light vertically through the through hole 10 at the center point of the first reflector 13 and shoots to the second reflector 11, which is reflected into a horizontal laser at the second reflector 11; 1. When rotating, the second reflecting device 11 also rotates to generate a 360° laser beam to detect and scan the horizontal plane;

Step 3, when the obstacle 12 is located in the reflection optical path of the second reflection device 11, it will reflect the laser light, and the laser light is reflected back through the reflection of the second reflection device 11 and the first reflection device 13, and after the convergence of the converging lens 14, the laser detector 15 receiving the converged laser light so that the laser distance measuring device 16 can perform subsequent processing;

Step 4, when the laser detector 15 receives the returned laser light, the laser distance measuring device 16 measures the time difference between the time t1 of the emitted laser pulse and the time _{t2 of} the received laser pulse or measures the time difference between the laser driving pulse and the received laser pulse Calculate the distance s between the obstacle and the UAV based on the time difference between them; because the encoder 7 is coaxially fixed with the motor 1, the system processor unit 17 calculates the rotation angle θ of the motor 1 at any time through the encoder 7, and reads the laser measurement at the same time. The distance s between the obstacle and the UAV calculated by the device 16 realizes the scanning and detection of the 360° obstacle 12 around the UAV, and performs obstacle avoidance processing.

Compared with the prior art, the present invention has the following advantages:

First, the present invention utilizes the characteristics of high laser resolution and strong anti-interference ability. When the motor rotates, it drives the reflection device to rotate instead of the 360° scanning detection of the radar itself. That is, on the basis of not increasing the motor, the detection effect achieved is comparable to that of the radar Its own 360° scanning detection has the same effect; thereby simplifying the structure of the obstacle avoidance system; at the same time, the installation position of this device can choose different installation methods according to the position of the propeller to meet the needs of different types of drones. The device of the present invention can be installed on each axis of the multi-axis UAV, and the number of installations can also be considered according to the actual situation. At the same time, the installation height of each scanning mirror is different, so that the detection of multiple planes can be realized and obtained. Stereo scene information. According to different installation positions of the propellers, the device of the present invention has multiple installation methods. It is different from existing obstacle avoidance devices that need to add motors or have poor obstacle avoidance effects.

Second, the present invention simplifies the structure of the obstacle avoidance system. The reflection device is fixedly connected to the motor shaft. When the motor rotates, the reflection device is driven to rotate, and 360° scanning can be realized without adding redundant motor equipment.

Description of drawings

FIG. 1 is a schematic structural diagram of the laser radar-based UAV obstacle avoidance device of the present invention.

Fig. 2 is a schematic diagram of the device of the present invention applied to an unmanned aerial vehicle.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. After reading the present invention, those skilled in the art all fall into the appended claims of the present application to the amendments of various equivalent forms of the present invention limited range.

As shown in Figure 1, a kind of unmanned aerial vehicle obstacle avoidance device based on laser radar, comprises the encoder 7 that is fixed under the motor 1 of unmanned aerial vehicle and is coaxially connected with motor 1; Also comprises laser drive circuit 8, and The laser 9 connected to the laser drive circuit 8 is fixed on the first reflection device 13 at the light output end of the laser 9. The laser beam emitted by the laser 9 just passes through the through hole 10 at the center point of the first reflection device 13, and is fixed on the through hole 10 to direct the light. The second reflection device 11 on the road and fixedly connected to the bottom end of the rotating shaft 6 of the motor 1 is located on the obstacle 12 on the reflection optical path of the second reflection device 11, and the first reflection device 13 simultaneously reflects the laser light reflected back by the second reflection device 11 , the converging lens 14 that is fixed on the reflection optical path of the first reflecting device 13, the laser detector 15 that is fixed on the converging optical path of the converging lens 14; the laser distance measuring device 16 that links to each other with the laser detector 15; also includes and described device code The system processor unit 17 connected with the device 7, the laser driving circuit 8 and the laser distance measuring device 16.

The second reflection device 11 is fixed on the bottom end of the motor shaft and rotates simultaneously with the motor. As a preferred solution, the best reflection effect can be achieved when the second reflection device 11 forms an included angle of 45 degrees with the horizontal direction.

The first reflector 13 has a through hole 10 at its central point, so that the laser light emitted by the laser 9 can pass through the first reflector 13 and reflect the laser reflected back by the second reflector 11 at the same time. As a preferred solution, the best reflection effect can be achieved when the first reflection device 13 forms an included angle of 45 degrees with the horizontal direction.

As a preferred solution, the lidar housing 18 packs the laser drive device 8, the laser 9, the second reflection device 11, the first reflection device 13, the converging lens 14, the laser detector 15, the laser distance measuring device 16, etc. to form a package as shown in Figure 2 The shown laser radar device 2 makes the installation and adjustment position of the device unlimited.

As shown in Figure 2, it is a schematic diagram of the application of the device of the present invention on an unmanned aerial vehicle. The motor 1 drives the propeller 4 to rotate to provide flight power for the unmanned aerial vehicle, wherein the output shaft 6 of the motor 1 is fixedly connected to the propeller 4 at the upper end, and the lower end is connected to the second propeller. Two reflectors 11 are fixedly connected, wherein the angle between the central point of the second reflector 11 and the center line of the motor shaft 6 is a (as a preferred solution, the best effect is achieved when a=45 °), the motor 1 and the propeller 4 The location can be installed on the frame 3 or below the frame 3. The number of laser radar devices 2 installed can also be determined by the actual situation. Using multiple laser radar devices 2 can realize 360° detection of different planes.

The laser driving circuit 8 of the present invention drives the laser 9 to generate a laser pulse. When the motor 1 rotates, it drives the encoder 7 and the second reflection device 11 fixed on its rotating shaft 6 to rotate. The rotation angle of the motor 1 at any time can be measured by the encoder 7 . The laser light vertically passes through the through hole 10 at the center point of the first reflecting device 13 and then vertically shoots to the second reflecting device 11, and is reflected by the second reflecting device 11 to become a horizontal laser. When the motor 1 rotates, it drives the second reflector 11 to rotate, so that 360° scanning and detection around the drone can be realized. When the obstacle 12 is located in the reflection optical path of the second reflection device 11, the laser light is reflected back. After being reflected by the second reflection device 11 and the first reflection device 13, the laser light passes through the converging lens 14 to achieve the effect of converging the laser light. The laser detector 15 receives the concentrated laser light for subsequent processing by the laser distance measuring device 16 . After the laser detector 15 receives the returned laser, the laser distance measuring device 16 measures the time difference between the time _t1 of the laser pulse and the time _t2 of the laser pulse (or the time difference between the laser drive pulse and the time t2 of the laser pulse) time difference) to calculate the distance s between the obstacle and the unmanned aerial vehicle, the calculation formula is as follows: s=(t ₂ -t ₁ )*v (v is the speed of the laser); the system processor unit 17 measures the rotation angle of the motor 1 by the encoder 7 θ, obtain the rotation angle position, and read the distance s between the obstacle and the UAV calculated by the laser ranging device 16 at the same time, and then realize the scanning detection of 360° obstacles around the UAV.

Claims (6)

1. an unmanned aerial vehicle obstacle avoidance device based on laser radar, it is characterized in that: comprise the encoder (7) that is fixed on below the motor (1) of unmanned aerial vehicle and is connected with the motor (1) coaxial measurement motor angle of rotation ); also comprise laser driving circuit (8), the laser device (9) that is connected with laser driving circuit (8), be fixed on the first reflection device (13) of laser device (9) light-emitting end, the laser beam that laser device (9) sends just Through the through hole (10) at the center point of the first reflector (13), the second reflector fixed on the direct light path of the through hole (10) and fixedly connected with the bottom end of the rotating shaft (6) of the motor (1) (11), the first reflecting device (13) reflects the laser light that the second reflecting device (11) reflects back simultaneously, is fixed on the converging lens (14) on the reflected light path of the first reflecting device (13), is fixed on the converging lens (14) ) the laser detector (15) on the converging optical path; the laser distance measuring device (16) linking to each other with the laser detector (15); The system processor unit (17) to which the device (16) is connected. 2. A kind of unmanned aerial vehicle obstacle avoidance device based on laser radar according to claim 1, it is characterized in that: described second reflection device (11) is fixed on the motor shaft bottom and rotates simultaneously with motor, and described first The two reflectors (11) form an included angle of 45 degrees with the horizontal direction. 3. The lidar-based UAV obstacle avoidance device according to claim 1, characterized in that: the first reflector (13) forms an included angle of 45 degrees with the horizontal direction. 4. A kind of unmanned aerial vehicle obstacle avoidance device based on lidar according to claim 1, is characterized in that: described laser detector (15) receives the laser light that converging lens (14) gathers, so that laser distance measuring device ( 16) Subsequent processing. 5. A kind of unmanned aerial vehicle obstacle avoidance device based on lidar according to claim 1, is characterized in that: described laser driving device (8), laser device (9), second reflecting device (11), first The reflection device (13), the converging lens (14), the laser detector (15) and the laser rangefinder (16) are packaged inside the laser radar housing (18), forming an obstacle avoidance device based on the laser radar, so that the device can be installed The adjustment position is not limited. 6. the obstacle avoidance method of the described laser radar-based unmanned aerial vehicle obstacle avoidance device of claim 1, is characterized in that: comprise the steps: Step 1, when the motor (1) rotates, it drives the encoder (7) and the second reflection device (11) fixed on its rotating shaft (6) to rotate simultaneously; Step 2, the laser drive circuit (8) drives the laser (9) to emit laser light vertically through the through hole (10) at the center point of the first reflector (13) and shoots to the second reflector (11). (11) place is reflected into the laser light of horizontal direction; Second reflection device (11) also rotates when motor (1) rotates, produces the laser beam of 360 °, and this horizontal plane is carried out detection scanning; Step 3, when the obstacle (12) is located in the reflection light path of the second reflection device (11), it will reflect the laser light, and the laser light is reflected back and passed through the reflection of the second reflection device (11) and the first reflection device (13), and then through the converging lens (14) After the convergence, the laser detector (15) receives the converged laser light so that the laser distance measuring device (16) performs subsequent processing; Step 4, when the laser detector (15) receives the returned laser, the laser distance measuring device (16) measures the time difference between the time t1 of the emitted laser pulse and the time _{t2 of} the received laser pulse or the measurement of the laser drive pulse and The time difference between receiving the laser pulse calculates the distance s of the obstacle from the UAV, because the encoder (7) is coaxially fixed with the motor (1), and the system processor unit (17) calculates the motor (1) through the encoder (7). 1) The rotation angle θ at any time, and at the same time read the distance s between the obstacle and the UAV calculated by the laser ranging device (16), to realize the scanning detection of the 360° obstacle (12) around the UAV, and avoid Troubleshooting.