阅读说明：本技术 一种未知环境下的消防机器人自主灭火方法 (Autonomous fire extinguishing method of fire-fighting robot in unknown environment ) 是由 李�瑞 刘琦 顾保虎 戴慎超 袁文正 张克富 潘强辉 于 2021-09-09 设计创作，主要内容包括：本发明公开了一种未知环境下的消防机器人自主灭火方法,属于消防机器人技术领域。发布目标点位,机器人进行自主SLAM探索,火源识别与定向,发现火源火源后,记录机器人此时的位置与航向,获取火源预警、火源温度、火源在图像中的面积大小与中心坐标信息,并把预警信息发送到远程遥控终端；机器人继续行走一段设定距离后进行火源识别与定向,记录在新位置的机器人位置与航向信息,获取火源预警、火源温度、火源在图像中的面积大小与中心坐标信息,并通过三角定位法计算火源中心的位置坐标并将火源中心所在点的位置坐标发送到远程遥控终端。本发明使得消防机器人在未知环境中进行自主行走与越障,能实现自主火源寻找与灭火,具有良好的应用前景。(The invention discloses an autonomous fire extinguishing method for a fire-fighting robot in an unknown environment, and belongs to the technical field of fire-fighting robots. Target point locations are distributed, the robot carries out autonomous SLAM exploration, fire sources are identified and oriented, after the fire sources are found, the position and the course of the robot at the moment are recorded, fire source early warning, fire source temperature, the area size and the center coordinate information of the fire sources in the image are obtained, and early warning information is sent to a remote control terminal; the robot continues to walk for a set distance and then carries out fire source identification and orientation, the position and the course information of the robot at a new position are recorded, fire source early warning, fire source temperature, the area size of the fire source in an image and center coordinate information are obtained, the position coordinate of the fire source center is calculated through a triangulation method, and the position coordinate of the fire source center is sent to the remote control terminal. The invention enables the fire-fighting robot to walk and cross obstacles autonomously in an unknown environment, can realize autonomous fire source searching and fire extinguishing, and has good application prospect.)

1. An autonomous fire extinguishing method of a fire-fighting robot in an unknown environment is characterized by comprising the following steps:

step 1: distributing a target fire extinguishing location to a fire fighting robot;

step 2: autonomous SLAM exploration is carried out on the fire-fighting robot, and fire source identification and positioning are carried out;

and step 3: after finding and positioning a fire source, the fire-fighting robot records the current position and course of the fire-fighting robot, acquires fire source early warning, fire source temperature, area size and center coordinate information of the fire source in an image and sends early warning information to a remote control terminal;

and 4, step 4: after the fire-fighting robot continues to walk for a set distance, identifying and orienting the fire source again, recording the position and course information of the fire-fighting robot when the fire source is found again, acquiring the early warning of the fire source, the temperature of the fire source, the area of the fire source in the image and the central coordinate information, calculating the position coordinate of the point of the center of the fire source by a triangulation location method, and sending the position coordinate of the point of the center of the fire source to a remote control terminal;

and 5: estimating the distance between the fire source and the fire-fighting robot by using a triangulation method, and judging whether the distance between the fire source and the fire-fighting robot is smaller than the range of a water cannon or not;

step 6: if so, opening the water cannon to supply water, extinguishing the fire, otherwise, turning to the step 1, and prompting the remote control operator to reissue the target fire extinguishing position.

2. A fire-fighting robot autonomous fire extinguishing method under unknown environment as recited in claim 1, characterized in that: the dynamic navigation and autonomous obstacle avoidance functions of the fire-fighting robot are established based on an outdoor laser radar, a high-precision GPS (global positioning system) and an SLAM (SLAM) technology, so that autonomous walking and obstacle avoidance can be realized in an unknown environment.

3. A fire-fighting robot autonomous fire extinguishing method under unknown environment as recited in claim 2, characterized in that: the three-light composite fire source detection sensor carries three cameras of visible light, infrared light and infrared thermal imaging, and in the process of fire source identification, the three cameras simultaneously acquire images, identify and process the images of the visible light and the infrared light cameras, and realize fire source identification and judgment by combining the processing technology of the infrared thermal imaging images.

4. A fire-fighting robot autonomous fire extinguishing method under unknown environment as recited in claim 3, characterized in that: the method for identifying and positioning the fire source comprises the following steps:

s1: the water cannon is controlled to rotate left and right and drives the fire source detection camera carried by the water cannon to synchronously rotate, so that the three-light composite fire source detection sensor can detect the fire source in the range of 180 degrees right in front of the fire-fighting robot;

s2: on the basis of synchronously obtaining different images of three cameras, the three-light composite fire source detection sensor firstly compares an RGB color image obtained by a visible light camera with an infrared spectrum color image obtained by an infrared light camera, and preliminarily judges that the region is a suspected fire source region and positions the region when the two images simultaneously meet the matching requirements of a fire source characteristic template corresponding to visible light and a fire source characteristic template corresponding to infrared light;

s3: further judging the infrared thermal image at the same time according to a set temperature threshold value aiming at the suspected fire source area, and judging the area as the fire source area if the average temperature of the area reaches or exceeds the set temperature threshold value;

s4: stopping the water cannon from rotating and giving fire source alarm information;

s5: segmenting a high-temperature region from the infrared thermograph by image cutting, extracting the boundary of the region, and calculating pixel points to obtain pixel point area characteristics and a central position of a fire source region;

s6: and enabling the water cannon to point to the central position of the fire source area, and determining the direction of the fire source through position information fed back by the water cannon and real-time course information of the robot.

5. A fire-fighting robot autonomous fire extinguishing method under unknown environment as recited in claim 4, characterized in that the distance estimation method of fire source and fire-fighting robot:

suppose a point F (X) for the center position of the fire_f,Y_f) Indicating that the robot is first atPoint A (X)_a,Y_a) Position-to-source identification and determination of source orientation, then at point B (X)_b,Y_b) Identifying and orienting the fire source again to construct a positioning triangle; wherein the coordinates of the point a and the point B are known in the global map, and the angle θ is the angle between the segment AB and the Y axis, so that the length l and θ of the segment AB can be determined, which can be expressed as

Firstly, a GPS positioning system is obtained to obtain a heading angle of the fire-fighting robot and a rotation angle of a gun barrel fed back by a water cannon relative to the heading of the fire-fighting robot, and an included angle theta between the gun barrel and a Y axis when the robot respectively locates at a point A and a point B can be calculated according to the two angles_aAnd theta_bThe value of (B) can further calculate three internal angles ≥ a, ≥ B and ≥ F in Δ ABF, as shown in equations (3) to (5):

∠A＝θ_a+θ (3)

∠B＝π-(θ_b+θ) (4)

∠F＝θ_b-θ_a (5)

in Δ ABF, AF distance l can be calculated using the sine theorem₁And a distance l of BF₂Thereby completing the estimation of the fire source distance,/₁And l₂Can be expressed as

Finally, the position coordinates (X) of the fire source in the global map can be obtained by the formula (6) or the formula (7)_f，Y_f) As shown in formulas (8) and (9):

X_f＝X_b+l₂·sin(θ_b) (8)

Y_f＝Y_b-l₂·cos(θ_b) (9)

the B coordinate (X) of the midpoint between the formula (8) and the formula (9)_b，Y_b) Derived from GPS positioning, variable θ_bCan be calculated to obtain₂From the calculation of equation (7), it can be seen that by identifying and orienting the ignition source at two points by the robot, the coordinates of the point F of the ignition source can be calculated by equations (8) and (9), and the distance from the point F of the ignition source to the point a or B can be further obtained.

Technical Field

The invention relates to the technical field of fire-fighting robots, in particular to an autonomous fire-fighting method of a fire-fighting robot in an unknown environment.

Background

In some fire scene, there is a certain danger in fire fighting, and once the fire is complicated, some unexpected casualties are easily caused. Especially in some chemical industry parks and coal production occasions, because there may be the leakage or explosion risk of dangerous gas or chemical, the fire fighter can threaten their health and personal safety to touch or expose in this environment. The fire-fighting robot capable of assisting or partially replacing fire fighters to carry out fire-fighting and fire-extinguishing work is developed, so that casualties of the fire fighters can be effectively reduced, and the fire fighters are assisted to carry out fire-fighting and fire rescue.

At present, some fire-fighting robot products, including domestic JZX-GL/A fire-fighting reconnaissance robots, JMX-LT50 type fire-fighting and fire-extinguishing robots, foreign WALK-MAN humanoid fire-fighting robots, Bear rescue robots and the like, have been developed at home and abroad and are practically applied to fire rescue. However, most of these existing fire-fighting robots adopt a remote control mode, and both walking and fire source searching and fire extinguishing processes depend too much on the operation level of remote control personnel.

Patent document CN 107224692 a discloses an autonomous aiming fire extinguishing method for wheeled fire-fighting robot. It includes the focus of confirming the flame source through video flame detection, measure flame source focus and robot contained angle, one section distance is removed wantonly to the fire-fighting robot, measure fire-fighting robot and flame source focus contained angle once more, rising cloud platform is certain to certain height and is measured focus and robot contained angle once more, calculate the position of flame source focus in three-dimensional space according to trigonometric function, remove the fire-fighting robot through integrated control, the initial velocity and the flow of fire monitor, make the flame source focus be located the effect that reaches accurate fire extinguishing on the orbit of fire monitor water jet. The autonomous fire extinguishing system of the fire-fighting robot comprises a sliding steering moving platform, a CCD camera, a liftable holder system, a fire monitor and a control system. The fire-extinguishing device realizes the function of autonomous fire extinguishing by autonomously aiming at a fire source and controlling the fire monitor landing point. However, the invention is an autonomous aiming method for a known fire source point, which cannot identify the fire source, so that autonomous detection, fire source identification, fire source positioning and autonomous fire extinguishing cannot be realized in unknown environments such as chemical industrial parks and coal production occasions, and the technical problems cannot be solved.

Patent document CN 105944270 a discloses a fire extinguishing method, a fire extinguishing system and a fire-fighting robot which can automatically aim at a fire source and spray water, the fire extinguishing method comprises the steps of measuring an included angle between the fire source direction of the fire-fighting robot at the initial position and the moving route of the fire-fighting robot, an included angle between the fire source direction of the fire-fighting robot at the final position and the moving route of the fire-fighting robot, and the moving distance of the fire-fighting robot, calculating the distance between the fire-fighting robot and the fire source when starting at the terminal position according to the trigonometric function, calculating the water cannon elevation angle according to the relational expression of the distance between the fire source and the water cannon elevation angle, carrying out cannon launching and fire extinguishing by the fire-fighting robot according to the calculated distance between the fire source and the water cannon elevation angle, the fire extinguishing system comprises a thermal imager, a holder system, a chassis servo system, a servo electric control type fire water monitor, an electronic water pressure meter and a control system, and the fire-fighting robot comprises the fire extinguishing system. The invention realizes the function of self-extinguishing by self-aiming at the fire source and distributing water for extinguishing fire. However, on one hand, the invention also performs autonomous aiming under the condition that the fire source point is known, and on the other hand, the invention only adopts the thermal imager to detect the position of the fire source, so that the fire source cannot be accurately identified, and the technical problem cannot be solved.

Disclosure of Invention

In view of the above, the present invention provides an autonomous fire extinguishing method for a fire-fighting robot in an unknown environment, which is capable of autonomously searching for a fire source, locating and extinguishing a fire, aiming at the defects of the prior art.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: an autonomous fire extinguishing method of a fire-fighting robot in an unknown environment comprises the following steps:

step 1: distributing a target fire extinguishing location to a fire fighting robot;

step 2: autonomous SLAM exploration is carried out on the fire-fighting robot, and fire source identification and positioning are carried out;

and step 3: after finding and positioning a fire source, the fire-fighting robot records the current position and course of the fire-fighting robot, acquires fire source early warning, fire source temperature, area size and center coordinate information of the fire source in an image and sends early warning information to a remote control terminal;

and 4, step 4: after the fire-fighting robot continues to walk for a set distance, identifying and orienting the fire source again, recording the position and course information of the fire-fighting robot when the fire source is found again, acquiring the early warning of the fire source, the temperature of the fire source, the area of the fire source in the image and the central coordinate information, calculating the position coordinate of the point of the center of the fire source by a triangulation location method, and sending the position coordinate of the point of the center of the fire source to a remote control terminal;

and 5: estimating the distance between the fire source and the fire-fighting robot by using a triangulation method, and judging whether the distance between the fire source and the fire-fighting robot is smaller than the range of a water cannon or not;

step 6: if so, opening the water cannon to supply water, extinguishing the fire, otherwise, turning to the step 1, and prompting the remote control operator to reissue the target fire extinguishing position.

Furthermore, the dynamic navigation and autonomous obstacle avoidance functions of the fire-fighting robot are established based on the outdoor laser radar, the high-precision GPS and the SLAM technology, so that autonomous walking and obstacle avoidance can be realized in an unknown environment.

Furthermore, the three-light composite fire source detection sensor carries three cameras of visible light, infrared light and infrared thermal imaging, and in the process of fire source identification, the three cameras simultaneously acquire images, identify and process the images of the visible light and the infrared camera, and realize fire source identification and judgment by combining the processing technology of the infrared thermal imaging image.

Further, the method for identifying and positioning the fire source comprises the following steps:

s1: the water cannon is controlled to rotate left and right and drives the fire source detection camera carried by the water cannon to synchronously rotate, so that the three-light composite fire source detection sensor can detect the fire source in the range of 180 degrees right in front of the fire-fighting robot;

s2: on the basis of synchronously obtaining different images of three cameras, the three-light composite fire source detection sensor firstly compares an RGB color image obtained by a visible light camera with an infrared spectrum color image obtained by an infrared light camera, and preliminarily judges that the region is a suspected fire source region and positions the region when the two images simultaneously meet the matching requirements of a fire source characteristic template corresponding to visible light and a fire source characteristic template corresponding to infrared light;

s3: further judging the infrared thermal image at the same time according to a set temperature threshold value aiming at the suspected fire source area, and judging the area as the fire source area if the average temperature of the area reaches or exceeds the set temperature threshold value;

s4: stopping the water cannon from rotating and giving fire source alarm information;

s5: segmenting a high-temperature region from the infrared thermograph by image cutting, extracting the boundary of the region, and calculating pixel points to obtain pixel point area characteristics and a central position of a fire source region;

s6: and enabling the water cannon to point to the central position of the fire source area, and determining the direction of the fire source through position information fed back by the water cannon and real-time course information of the robot.

Further, a method for estimating the distance between the fire source and the fire-fighting robot comprises the following steps:

suppose a point F (X) for the center position of the fire_f,Y_f) Indicating that the robot first makes a point A (X)_a,Y_a) Position-to-source identification and determination of source orientation, then at point B (X)_b,Y_b) Identifying and orienting the fire source again to construct a positioning triangle; wherein the coordinates of point A and point B in the global mapAs is known, the angle θ is the angle between the segment AB and the Y axis, so that the lengths l and θ of the segment AB can be determined, and can be expressed as

Firstly, a GPS positioning system is obtained to obtain a heading angle of the fire-fighting robot and a rotation angle of a gun barrel fed back by a water cannon relative to the heading of the fire-fighting robot, and an included angle theta between the gun barrel and a Y axis when the robot respectively locates at a point A and a point B can be calculated according to the two angles_aAnd theta_bThe value of (B) can further calculate three internal angles of ^ A, < B and < F in < delta > ABF, as shown in formulas (3) to (5):

∠A＝θ_a+θ (3)

∠B＝π-(θ_b+θ) (4)

∠F＝θ_b-θ_a (5)

in Δ ABF, AF distance l can be calculated using sine theorem₁And a distance l of BF₂Thereby completing the estimation of the fire source distance,/₁And l₂Can be expressed as

Finally, the position coordinates (X) of the fire source in the global map can be obtained by the formula (6) or the formula (7)_f,Y_f) As shown in formulas (8) and (9):

X_f＝X_b+l₂·sin(θ_b) (8)

Y_f＝Y_b-l₂·cos(θ_b) (9)

the B coordinate (X) of the midpoint between the formula (8) and the formula (9)_b,Y_b) Derived from GPS positioning, variable θ_bCan be calculated to obtain₂From the calculation of equation (7), it can be seen that by identifying and orienting the ignition source at two points by the robot, the coordinates of the point F of the ignition source can be calculated by equations (8) and (9), and the distance from the point F of the ignition source to the point a or B can be further obtained.

Because the existing fire-fighting robot moves to the vicinity of a fire source in a manual remote control mode to extinguish a fire, when designing an autonomous fire-fighting robot, a person skilled in the art generally thinks that the fire-fighting robot autonomously aims at the fire source to realize rapid fire extinguishing, for example, an autonomous aiming fire-source water-spraying fire-extinguishing method disclosed in the patent publication No. CN 105944270A, includes measuring an included angle between a fire source direction of the fire-fighting robot at an initial position and a moving route of the fire-fighting robot, an included angle between a fire source direction of the fire-fighting robot at a terminal position and a moving route of the fire-fighting robot, and a distance of the fire-fighting robot moving, calculating a distance between the fire-fighting robot at the terminal position and the fire source according to a trigonometric function, calculating a water monitor elevation angle according to a relational expression of the fire source distance and the water monitor elevation angle, the fire-fighting robot fire-fighting according to the calculated fire source distance and water monitor elevation angle, the fire extinguishing system comprises a thermal imager, a holder system, a chassis servo system, a servo electric control type fire water monitor, an electronic water pressure meter and a control system, and the fire-fighting robot comprises the fire extinguishing system. Also disclosed in patent publication No. CN 107224692 a is a method for self-aiming fire extinguishing by a wheeled fire-fighting robot. It includes the focus of confirming the flame source through video flame detection, measure flame source focus and robot contained angle, one section distance is removed wantonly to the fire-fighting robot, measure fire-fighting robot and flame source focus contained angle once more, rising cloud platform is certain to certain height and is measured focus and robot contained angle once more, calculate the position of flame source focus in three-dimensional space according to trigonometric function, remove the fire-fighting robot through integrated control, the initial velocity and the flow of fire monitor, make the flame source focus be located the effect that reaches accurate fire extinguishing on the orbit of fire monitor water jet. Since the autonomous fire extinguishing methods disclosed in the above two patent documents perform autonomous fire extinguishing when the location of the fire source is known, the technical solutions of autonomous search, fire source identification and location, and fire extinguishing according to the present application are not easy to be considered by those skilled in the art.

Compared with the prior art, the invention has the following beneficial effects:

the invention relates to an autonomous fire extinguishing method of a fire-fighting robot in an unknown environment. Firstly, distributing target point locations to fire-fighting robots according to a building map of a park, enabling the robots to conduct autonomous SLAM exploration around the park, and meanwhile conducting autonomous obstacle avoidance, fire source identification and orientation. After finding and positioning a fire source, the fire-fighting robot records the current position and course of the robot, acquires fire source early warning, fire source temperature, area size and center coordinate information of the fire source in an image and sends early warning information to a remote control terminal; and then, the robot continues to walk for a set distance and then carries out fire source identification and orientation again, the position and the course information of the robot at the new position are recorded again, fire source early warning, fire source temperature, the area size of the fire source in the image and center coordinate information are obtained, the position coordinate of the fire source center point is calculated through a triangulation method, and the position coordinate of the fire source center point is sent to the remote control terminal. When the distance between the fire source and the robot is less than the maximum range of the fire-fighting robot water cannon, the fire-fighting robot is directly stopped to carry out fire-fighting work; otherwise, prompting a remote control operator to release the target fire extinguishing position, and stopping the robot to perform fire extinguishing work after the robot reaches the target fire extinguishing position through autonomous navigation and identifying and orienting a fire source. Therefore, the fire-fighting robot can realize autonomous navigation, autonomous fire source searching, positioning and fire extinguishing in unknown environment, so that the fire-fighting robot can replace firemen to enter dangerous places such as chemical industrial parks, coal production occasions and the like for routing inspection and fire extinguishing, casualties of the firemen are effectively reduced, and the firemen are assisted to extinguish fire and rescue fire.

Drawings

FIG. 1 is a schematic flow diagram of an embodiment of the present invention;

FIG. 2 is a schematic flow chart of fire source identification and location in an embodiment of the present invention;

FIG. 3 is a schematic diagram of triangulation in an embodiment of the invention;

FIG. 4 is a software framework diagram of dynamic navigation of a fire fighting robot in an embodiment of the present invention;

fig. 5 is a hardware connection diagram of a fire-fighting robot control system in an embodiment of the invention.

Detailed Description

In order to better understand the present invention, the following examples are further provided to clearly illustrate the contents of the present invention, but the contents of the present invention are not limited to the following examples. In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details.

As shown in fig. 1, an autonomous fire extinguishing method for a fire-fighting robot in an unknown environment is implemented by combining autonomous obstacle avoidance, fire source identification and orientation technologies based on dynamic navigation, and includes the following steps:

step 1: distributing a target fire extinguishing location to a fire fighting robot;

step 2: autonomous SLAM exploration is carried out on the fire-fighting robot, and fire source identification and positioning are carried out;

and step 3: after finding and positioning a fire source, the fire-fighting robot records the current position and course of the fire-fighting robot, acquires fire source early warning, fire source temperature, area size and center coordinate information of the fire source in an image and sends early warning information to a remote control terminal;

and 4, step 4: after the fire-fighting robot continues to walk for a set distance, identifying and orienting the fire source again, recording the position and course information of the fire-fighting robot when the fire source is found again, acquiring the early warning of the fire source, the temperature of the fire source, the area of the fire source in the image and the central coordinate information, calculating the position coordinate of the point of the center of the fire source by a triangulation location method, and sending the position coordinate of the point of the center of the fire source to a remote control terminal;

and 5: estimating the distance between the fire source and the fire-fighting robot by using a triangulation method, and judging whether the distance between the fire source and the fire-fighting robot is smaller than the range of a water cannon or not;

step 6: if so, opening the water cannon to supply water, extinguishing the fire, otherwise, turning to the step 1, and prompting the remote control operator to reissue the target fire extinguishing position.

The dynamic navigation and autonomous obstacle avoidance functions of the fire-fighting robot are established based on an outdoor laser radar, a high-precision GPS (global positioning system) and an SLAM (SLAM) technology, so that autonomous walking and obstacle avoidance can be realized in an unknown environment.

The three-light composite fire source detection sensor carries three cameras of visible light, infrared light and infrared thermal imaging, and in the process of fire source identification, the three cameras simultaneously acquire images, identify and process the images of the visible light and the infrared light cameras, and realize fire source identification and judgment by combining the processing technology of the infrared thermal imaging images.

As shown in fig. 2, the method for identifying and locating a fire source includes the following steps:

s1: the water cannon is controlled to rotate left and right and drives the fire source detection camera carried by the water cannon to synchronously rotate, so that the three-light composite fire source detection sensor can detect the fire source in the range of 180 degrees right in front of the fire-fighting robot;

s2: on the basis of synchronously obtaining different images of three cameras, the three-light composite fire source detection sensor firstly compares an RGB color image obtained by a visible light camera with an infrared spectrum color image obtained by an infrared light camera, and preliminarily judges that the region is a suspected fire source region and positions the region when the two images simultaneously meet the matching requirements of a fire source characteristic template corresponding to visible light and a fire source characteristic template corresponding to infrared light;

s3: further judging the infrared thermal image at the same time according to a set temperature threshold value aiming at the suspected fire source area, and judging the area as the fire source area if the average temperature of the area reaches or exceeds the set temperature threshold value;

s4: stopping the water cannon from rotating and giving fire source alarm information;

s5: segmenting a high-temperature region from the infrared thermograph by image cutting, extracting the boundary of the region, and calculating pixel points to obtain pixel point area characteristics and a central position of a fire source region;

s6: and enabling the water cannon to point to the central position of the fire source area, and determining the direction of the fire source through position information fed back by the water cannon and real-time course information of the robot.

As shown in fig. 3, the method for estimating the distance between the fire source and the fire-fighting robot comprises the following steps:

assume the center of the fire for point F (Xf, Y)_f) Indicating that the robot first makes a point A (X)_a,Y_a) Position-to-source identification and determination of source orientation, then at point B (X)_b,Y_b) Identifying and orienting the fire source again to construct a positioning triangle; wherein the coordinates of the point a and the point B are known in the global map, and the angle θ is the angle between the segment AB and the Y axis, so that the length l and θ of the segment AB can be determined, which can be expressed as

Firstly, a GPS positioning system is obtained to obtain a heading angle of the fire-fighting robot and a rotation angle of a gun barrel fed back by a water cannon relative to the heading of the fire-fighting robot, and an included angle theta between the gun barrel and a Y axis when the robot respectively locates at a point A and a point B can be calculated according to the two angles_aAnd theta_bThe value of (B) can further calculate three internal angles of ^ A, < B and < F in < delta > ABF, as shown in formulas (3) to (5):

∠A＝θ_a+θ (3)

∠B＝π-(θ_b+θ) (4)

∠F＝θ_b-θ_a (5)

in Δ ABF, AF distance l can be calculated using sine theorem₁And a distance l of BF₂Thereby completing the estimation of the fire source distance,/₁And l₂Can be expressed as

l₁ sin(θ_a+θ)＝l₂sin(π-(θ_b+θ))

l₁cos(θ_a+θ)+l₂cos(π-(θ_b+θ))＝l

Finally, the position coordinates (X) of the fire source in the global map can be obtained by the formula (6) or the formula (7)_f,Y_f) As shown in formulas (8) and (9):

X_f＝X_b+l₂·sin(θ_b) (8)

Y_f＝Y_b-l₂·cos(θ_b) (9)

the B coordinate (X) of the midpoint between the formula (8) and the formula (9)_b,Y_b) Derived from GPS positioning, variable θ_bCan be calculated to obtain₂From the calculation of equation (7), it can be seen that by identifying and orienting the ignition source at two points by the robot, the coordinates of the point F of the ignition source can be calculated by equations (8) and (9), and the distance from the point F of the ignition source to the point a or B can be further obtained.

The fire-fighting robot provided by the embodiment of the invention adopts a crawler-type travelling mechanism and is provided with a water cannon, a spraying device, a camera, an environment monitoring sensor, a wireless communication device and the like. The left side and the right side of the robot are respectively provided with a crawler belt, the robot is driven by a crawler belt driving module consisting of a driving wheel, a guide wheel, a tension wheel and a bearing wheel set, and the moving functions of advancing, retreating, steering and the like of the robot are realized by controlling the rotating speed and the steering of the driving wheels on the crawler belts at the two sides. Wherein, the driving wheel radius of setting in the robot rear portion is 150mm, and leading wheel and take-up pulley set up in the front portion of robot and form the rake angle of about 45 with the track together. Each wheel in the bearing wheel set is provided with an independent spring suspension for pressing the crawler belt and buffering the load fluctuation. The main parameters and performance indexes are shown in table 1.

TABLE 1 fire-fighting robot main parameters and Performance indexes

On the basis, in order to realize the functions of autonomous fire source searching and autonomous fire extinguishing of the robot in the unknown environment, a laser radar for outdoor navigation, a RTK-based GPS high-precision positioning system, a three-light composite fire source detection sensor and a wireless communication module are additionally arranged on the robot body, and the laser radar is used for realizing autonomous navigation, autonomous fire source searching and fire extinguishing of the robot in the unknown environment.

The software framework for the dynamic navigation of the fire-fighting robot is shown in fig. 4. The laser radar node is used for acquiring laser radar ranging data; the GPS odometer node is used for acquiring GPS data and converting the GPS data into odometer information required by autonomous navigation; the chassis control node is used for receiving the movement instruction and controlling the driving motor to realize the movement of the robot. In the dynamic navigation process, firstly, a target point position needs to be issued to the robot, the real-time construction of an environment map is completed through distance information acquired by a laser radar, positioning information acquired by a GPS and odometer positioning information, global path planning and local path planning of the robot on the real-time map are realized in a navigation node, and the path planning is updated in real time in the robot walking process. And simultaneously, issuing a speed control instruction, receiving the speed control instruction by the chassis control node, and driving the robot chassis to run according to the planned route to finish autonomous navigation in the unknown environment.

The three-light composite fire source detector is selected to accurately identify the fire source, and is fixedly installed on the water cannon barrel with the two-dimensional rotation function and keeps the same direction with the water cannon barrel. The water cannon barrel can rotate in two dimensions, and the relative angle between the water cannon barrel and the fire-fighting robot body at any moment can be detected in real time. Therefore, the fire source can be found by controlling the rotation of the water cannon barrel.

On the basis that the fire-fighting robot has the two capabilities, a remote operator can determine a proper target position and send the target position to the fire-fighting robot. And after receiving the target position, the robot performs autonomous navigation and obstacle avoidance in an unknown environment, and automatically controls the water cannon barrel to rotate at the specific target position to search for a fire source. After the robot identifies and positions the fire source, the included angle between the gun barrel of the water cannon and the ground is automatically adjusted upwards to a specified angle, and the azimuth information of the fire source is sent to a remote operator. The water source is controlled to be communicated with the water pressure by a remote operator, fire is put out, and meanwhile, the water pipe swings left and right in a small range according to a set program, so that the coverage range of the water faucet is expanded, and the water faucet direction deviation caused by errors of the wind direction and the angle is prevented.

As shown in fig. 5, the fire-fighting robot control system adopts a high-performance embedded industrial personal computer as a main controller, and a PCIE board card carried on the industrial personal computer sends a PWM pulse signal to a driving motor and receives a pulse generated in a motor rotation process. The motion control of the industrial personal computer on the water cannon is realized through a J1939 communication protocol based on a CAN bus. In the aspect of perceiving the self state and the surrounding environment, the current position and the course information of the robot obtained by the high-precision GPS and the surrounding environment obstacle information detected by the laser radar are respectively sent to the industrial personal computer through the RS232 interface and the network cable interface. The information of the gas sensor, the temperature and humidity sensor and the power management module is read by the single chip microcomputer board and then fed back to the industrial personal computer through the RS232 interface, and then the information is transmitted to the remote control box of the upper computer through the wireless data transmission module by the industrial personal computer. In addition, the fire source identification structure of the fire source detection sensor is sent to the industrial personal computer through the network port, and simultaneously, real-time video information of the fire source identification structure and video information obtained by the camera are transmitted to the upper computer remote control box through the wireless image transmission module, so that the field real-time condition is provided for remote control operators.

The three-light composite fire source detection sensor adopts a TCP communication mechanism to transmit a fire source identification and positioning result to the industrial personal computer, the communication data of the sensor adopts a pure json character string, and the information output mainly comprises the following two structural body data as shown in the following table 2.

TABLE 2 three light composite fire source detection sensor result output

As can be seen from table 2, the three-light composite fire source detection sensor can output fire source early warning, fire source temperature, and area size and center coordinate information of the fire source in the image after completing fire source identification and positioning.

Experiments and analyses

1. Experiment for identifying fire source

In the fire source identification experiment, burning waste wood and cardboard form the fire source, set up in the place of about 40m in front of fire-fighting robot. After the water cannon is fully combusted until the fire source is larger than 0.3m multiplied by 0.3m, the water cannon is controlled to swing in a reciprocating mode within 180 degrees right ahead, the three-light composite fire source detection sensor carried on the water cannon barrel is enabled to identify the fire source, and the feedback information of the sensor is read to verify the accuracy of fire source identification. The data of 10 replicates are shown in Table 3.

TABLE 3 fire source identification experimental data

As can be seen from the data in table 3, the identified fire source temperature is between 250 and 350 ℃, and the general wood burning temperature is above four hundred degrees celsius, and usually about six hundred degrees celsius. Considering that the heat radiation decreases with increasing distance, it is reasonable to experiment the data.

The information feedback frequency of the three-light composite fire source detector is about 0.67Hz, and the swing speed range of the water cannon is 5-20 degrees/s. The experimental result shows that under the condition that the size of the fire source meets the requirement, the fire source identification accuracy rate reaches 100 percent and is higher than the set index of 90 percent.

2. Robot obstacle avoidance and positioning experiment

In order to verify the obstacle avoidance performance and the positioning precision of the fire-fighting robot, the robot obstacle avoidance and positioning experiment is carried out in the dynamic navigation process, and the experiment method comprises the following steps: the robot is at initial position (0, 0), a target point position (x, y) is given, 2-3 obstacles are arranged between the two positions, the robot is required to avoid the arranged obstacles in autonomous navigation, and autonomous navigation is carried out to the target point. Then, the actual arrival position of the robot is measured, and the positioning accuracy of the robot is verified by comparing the given target positions. The experiment was repeated 10 times and the positioning data are shown in table 4.

Table 4 positioning experimental data

As can be seen from the data in Table 4, the positioning error of the robot in the dynamic navigation is within +/-0.4 m in the X direction and the Y direction, and the positioning precision can ensure that the function of self-extinguishing is realized in the dynamic navigation process of the fire-fighting robot.

3. Autonomous fire extinguishing experiment

In the autonomous fire extinguishing test, the fire-fighting robot firstly conducts autonomous SLAM exploration of a park environment and conducts fire source identification and orientation, after the fire source is detected, the fire source is navigated to a fire extinguishing point to conduct secondary fire source identification and orientation, the position of the fire source in a global map is determined through a triangular positioning method, meanwhile, the distance between the fire source and the fire extinguishing point is determined, the pitch angle of a water cannon is adjusted, and the fire extinguishing distance is controlled by matching with the pressure of a rear water pump to extinguish fire. The experimental data for 5 replicates are shown in table 5.

TABLE 5 autonomous fire extinguishing test data

As can be seen from the data in Table 5, in 5 experiments, the fire source orientation accuracy obtained by calculation according to the detection data is within 3 degrees, the maximum distance estimation error is about 8m, and the feasibility of the fire source identification orientation method and the triangular positioning method for estimating the fire source distance is verified.

Conclusion

According to the requirement that the fire-fighting robot carries out fire-fighting rescue in a chemical industry park with explosion possibility or a coal industry unit and other fire scenes instead of firemen, the autonomous fire source searching and fire-fighting technology of the fire-fighting robot is developed. Specifically, firstly, on the basis of introducing a structure and a control system of the fire-fighting robot, the technical requirements of the fire-fighting robot for independently searching a fire source and extinguishing fire in an unknown environment are determined; secondly, analyzing the working environment of the fire-fighting robot, and providing a technical scheme for the fire-fighting robot to independently find a fire source and extinguish fire; then, the autonomous walking and obstacle avoidance of the fire-fighting robot in an unknown environment are realized based on the SLAM technology, and a method and a technology suitable for the robot to autonomously find a fire source and position the fire source are developed; and finally, performing effectiveness verification on the fire source independently found and the fire extinguishing technology of the fire-fighting robot through simulation and experiments. Experimental results show that the developed fire-fighting robot autonomous fire source searching and extinguishing technology can enable the fire-fighting robot to independently walk and cross obstacles in an unknown environment, the positioning precision is less than 0.4m, the fire source identification rate is greater than 90%, autonomous fire source searching and extinguishing can be achieved, and the fire-fighting robot autonomous fire source searching and extinguishing device has a good application prospect.

Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.