Protective mask intelligent control method and device based on intelligent safety helmet

Abstract

The invention provides a protective mask intelligent control method and device based on an intelligent safety helmet. The device comprises the safety helmet, a mask body, a gas supply cover, an oxygen bottle, a filter element, a valve, a gas concentration sensor and an oxygen concentration sensor. Therefore, when the gas concentration is larger than the gas concentration threshold value, the control module in the safety helmet controls the valve to isolate the filter element from the gas supply cover and controls the oxygen bottle to output gas at the first standard gas output; when the gas concentration is smaller than the gas concentration threshold value, the control valve enables the filter element to be communicated with the gas supply cover, and the gas output of the oxygen bottle is adjusted in real time according to the detection value of the oxygen concentration sensor; therefore, intelligent control over the gas output of the oxygen bottle is achieved, the service life of the oxygen bottle with the same size is prolonged, the burden of miners is reduced, meanwhile, sufficient supply of oxygen is guaranteed, and it is guaranteed that the miners can evacuate rapidly.

Description

Technical Field

[0001] The present invention relates to the field of intelligent control technology, and in particular to an intelligent control method and device for a protective mask based on an intelligent safety helmet. Background Art

[0002] With the rapid development of electronic technology, the hard hats used to protect miners in mineral mining are becoming more and more intelligent, that is, the use of smart hard hats is becoming more and more popular. During use, in order to facilitate timely communication with miners, supervisors can initiate voice communication with the smart hard hat. Since most mining processes are noisy environments, in order to be able to hear the content of the voice communication clearly and reduce noise interference during the mining process, the patent document with authorization announcement number CN110262326A discloses an "intelligent control method and device for the protective mask on the smart hard hat". The protective mask on the smart hard hat can be automatically controlled to start by using environmental noise, thereby reducing the interference of environmental noise on voice communication and realizing intelligent and automatic control of the protective mask. From the above, it can be seen that the intelligent and automated control of protective masks can be regarded as a general control and regulation system; protective masks and smart safety helmets are the functional units of this system; but under normal circumstances, protective masks are also used in conjunction with oxygen cylinders during mining to ensure the safety of miners under different mining conditions; but since miners need to carry oxygen cylinders, if the oxygen cylinders are too heavy, it will affect the miners' movements, and if the oxygen cylinders are too light, they cannot support the miners for a long time; it is too difficult for miners to actively adjust the oxygen output in real time; therefore, there is an urgent need for a control method and device that can realize intelligent adjustment of the oxygen output. Summary of the Invention

[0003] The purpose of the present invention is to design an intelligent control method and device for a protective mask based on a smart helmet to solve the problems raised by the background technology. To achieve the above purpose, the present invention provides a protective mask based on a smart helmet, comprising a helmet that can form an ad hoc network and generate a first evacuation route, a mask body that transmits signals to the helmet through a quick plug-in method, and an oxygen cylinder connected to the air supply hood in the mask body, the air supply hood is connected to the outside world through a filter element, and a valve is provided between the filter element and the air supply hood; the helmet detects the gas concentration and oxygen concentration in the environment in real time, and the control module in the helmet controls the opening and closing of the valve and the gas output of the oxygen cylinder according to the gas concentration and oxygen concentration; Furthermore, a gas concentration sensor and an oxygen concentration sensor connected to the control module are provided inside the safety helmet.

[0004] Furthermore, a piezoelectric film respiratory rate sensor connected to the control module is provided inside the air supply hood to measure the respiratory rate of workers during the evacuation process.

[0005] Furthermore, a display screen is provided on the hood body above the air supply hood, and a compass is provided on the display screen for guiding the workers.

[0006] The present invention also discloses an intelligent control method for a protective mask, which is as follows: a control module receives detection data from a gas concentration sensor and an oxygen concentration sensor in a safety helmet in real time; When the detection value of the gas concentration sensor is greater than the gas concentration threshold, the control module controls the valve to isolate the filter element from the gas supply hood, and controls the oxygen cylinder to output gas at the first standard output volume; When the detection value of the gas concentration sensor is less than the gas concentration threshold, the control module controls the valve to connect the filter element with the gas supply hood, and adjusts the gas output of the oxygen cylinder in real time according to the detection value of the oxygen concentration sensor.

[0007] Furthermore, the control module intermittently collects the total length L of the mine, and instructs the front workers between the mine exit and the point L / a from the mine exit to evacuate in an equidistant and side-by-side manner, and instructs the middle and rear workers between the point L / a from the mine exit and the point L from the mine exit to evacuate along the first evacuation route designated by the safety helmet, where a is the safety factor, 2≤a≤3; The control module forms a gas concentration cloud map based on the detection values ​​of the gas concentration sensor fed back by the front-end workers, and connects the center points of the areas below the gas concentration threshold in the gas concentration cloud map to form a second evacuation route for the middle and back-end workers to evacuate.

[0008] Furthermore, the control module controls the direction of the compass through the first evacuation route and the second evacuation route to guide the middle and back-end workers to walk along the first evacuation route and the second evacuation route.

[0009] Furthermore, a first oxygen concentration threshold value Y1 is pre-input into the control module. When the detection value of the gas concentration sensor is less than the gas concentration threshold value and the real-time oxygen concentration Yi is greater than Y1, the control module controls the oxygen cylinder to stop supplying oxygen; wherein Y1>19.5%.

[0010] Furthermore, the control module pre-inputs the second standard gas output volume C2 of the oxygen cylinder and the oxygen concentration threshold value Y0. When the detection value of the gas concentration sensor is less than the gas concentration threshold value and the real-time oxygen concentration Yi<19.5%, the control module controls the actual gas output volume Ci=bxC2xY0 / Yi of the oxygen cylinder through C2, Y0 and Yi; b is a pre-input constant, and Y0<19.5%.

[0011] Furthermore, the control module corrects the output volume of the oxygen cylinder upward when the breathing rate increases.

[0012] Furthermore, the control module pre-inputs the standard breathing frequency H0 and the first standard oxygen output volume C1. When the detection value of the gas concentration sensor is greater than the gas concentration threshold, the control module determines the actual output volume of the oxygen cylinder Ci=cxC1xHi / H0 through H0, C1 and the actual breathing frequency Hi; c is a pre-input constant.

[0013] Furthermore, the standard breathing frequency H1 is pre-input into the control module. When the detection value of the gas concentration sensor is less than the gas concentration threshold, the control module determines the actual gas output of the oxygen cylinder Ci=dxC2xHi / H1+exC2x(Y0 / Yi) through C2, Y0, Yi, H1 and the actual breathing frequency Hi, where d and e are pre-input proportional coefficients.

[0014] Furthermore, along the evacuation direction of the second evacuation route, the control module will sequentially group three consecutive center points to form several path correction groups, and take the distance from the first center point to the second center point in each path correction group as D1, the distance from the first center point to the third center point as D2, and the distance from the second center point to the third center point as D3. If D1+D3≥2D2, the control module will correct the second evacuation route in which the three center points in the path correction group are sequentially connected to become a second evacuation route in which the first center point and the third center point are connected.

[0015] Furthermore, the control module simulates and calculates the maximum inscribed circle radius R in the area of ​​the second center point in each path correction group based on the gas concentration cloud map. The center of the inscribed circle is the center point of the area. If D2≤D1+D3-2R+fxqxR / R0 exists, the control module corrects the second evacuation route connecting the three center points in the path correction group in sequence to the second evacuation route connecting the first center point and the third center point. The standard oxygen consumption required for the miner to walk out of the area with a standard inscribed circle radius of R0 is Q. When the miner walks with the gas output of the oxygen cylinder as the first standard gas output, the distance the miner walks when the oxygen consumption reaches Q is q, and f is a pre-input constant.

[0016] Compared with the prior art, the present invention has the following beneficial effects: an air supply hood that can filter external air and is connected to the oxygen cylinder is provided in the cover body of the present invention, and data transmission is realized between the cover body and the safety helmet; therefore, when the gas concentration is greater than the gas concentration threshold, the control module in the safety helmet controls the valve to isolate the filter element from the air supply hood, and controls the oxygen cylinder to output at a first standard gas output; when the gas concentration is less than the gas concentration threshold, the control valve is controlled to connect the filter element with the air supply hood, and the gas output of the oxygen cylinder is adjusted in real time according to the detection value of the oxygen concentration sensor; thereby, intelligent control of the gas output of the oxygen cylinder is realized, thereby extending the use time of oxygen cylinders of the same volume, reducing the burden on miners while ensuring sufficient oxygen supply, thereby ensuring that miners can evacuate quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the second evacuation route.

[0019] Among them: 1. Display screen; 2. Safety helmet; 3. Cover body; 4. Air supply cover; 5. Filter element; 6. Oxygen cylinder. DETAILED DESCRIPTION

[0020] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0021] See also Figure 1In the process of mineral mining, underground operations and blasting scenes are usually accompanied. Both scenes have a lot of dust, or the overflow of harmful gases (gas) during the blasting process, or the insufficient oxygen concentration. At this time, miners need to wear protective masks connected to oxygen cylinders for protection for a period of time; but because miners need to carry oxygen cylinders, if the oxygen cylinders are too heavy, it will affect the miners' movements, and if the oxygen cylinders are too light, they cannot support the miners for a long time; it is too difficult for miners to actively adjust the oxygen output in real time; therefore, the present invention provides a protective mask based on a smart safety helmet, comprising a safety helmet 2, a cover body 3 that generates signal transmission with the safety helmet 2 by quick plugging, and an air supply hood 4 connected to the cover body 3. The oxygen cylinder 6 is connected to the air supply hood 4 of the present invention, and the air supply hood 4 is connected to the outside world through the filter element 5. A valve is provided between the filter element 5 and the air supply hood 4. The safety helmet 2 detects the gas concentration and oxygen concentration in the environment in real time. The control module in the safety helmet 2 controls the on and off of the valve and the gas output of the oxygen cylinder 6 according to the gas concentration and oxygen concentration. Among them, the safety helmet 2 and the cover body 3 are in a detachable form, that is, a quick-plug form. When the mask is not needed, the safety helmet 2 is separated from the cover body 3 to ensure the normal work of the miner, and the wearing method of the air supply hood 4 can adopt a common adjustable form, and a gas concentration sensor and an oxygen concentration sensor are provided inside the safety helmet 2 for transmitting the gas concentration and oxygen concentration in the environment to the control module in real time.

[0022] In addition, the present invention also provides an intelligent control method for a protective mask, namely, a control module can control the gas output volume of the oxygen cylinder 6 and the opening and closing of the valve. When the detection value of the gas concentration sensor is greater than the gas concentration threshold, the control module controls the valve to isolate the filter element 5 from the gas supply hood 4 and control the oxygen cylinder 6 to output gas at a first standard gas output volume to prevent miners from poisoning. When the detection value of the gas concentration sensor is less than the gas concentration threshold, the control module controls the valve to connect the filter element 5 to the gas supply hood 4 and adjusts the gas output volume of the oxygen cylinder 6 in real time according to the detection value of the oxygen concentration sensor, thereby realizing intelligent control of the gas output volume of the oxygen cylinder 6, extending the service life of oxygen cylinders 6 of the same volume, reducing the burden on miners, ensuring an adequate oxygen supply, and filtering external gases, thereby ensuring long-term work for miners. The gas concentration threshold can be determined by the degree of gas filtration of the filter element 5. In this embodiment, the filter element 5 adopts the filter element structure of the self-priming filter mask. At this time, the gas concentration threshold can be a value between 0.1% and 0.5%.

[0023] Furthermore, when an accident occurs inside a mine, harmful gases (such as gas and coal dust) are released into the air, increasing their concentration and posing a threat to the health of miners. In this situation, the oxygen cylinders of the present invention are particularly important. However, after an accident, miners must be evacuated promptly to ensure the safety of mine workers. While the present invention can intelligently adjust the gas and oxygen concentrations, it cannot provide a preferred evacuation route for miners, such as requiring them to evacuate to areas with lower gas concentrations and higher oxygen concentrations. In order to solve the above problems, the patent document with the authorization announcement number CN112690529B provides a mine safety helmet; the safety helmet detects the gas concentration, oxygen concentration and position coordinates of the current position through a gas concentration sensor, an oxygen concentration sensor and a positioning module, and realizes self-organizing network with the mine safety helmets carried by other personnel in the mine through a wireless communication module, and interacts with the gas concentration and oxygen concentration of each position. When the gas concentration at the current position is too high or the oxygen concentration is too low, an alarm is issued, and an evacuation route is formulated in combination with the gas concentration, oxygen concentration and position coordinates of other positions to guide the safe evacuation of the personnel carrying the mine safety helmet; thus, When an accident occurs inside a mine, the safety helmet can plan an evacuation route while realizing intelligent oxygen supply to the oxygen cylinder; thereby increasing the service life of the oxygen cylinder and further ensuring the safety of the miners; and the function of the safety helmet in this patent does not conflict with the function of the safety helmet mentioned in the background technology. Specifically, the device mentioned in the background technology can be adaptively adjusted according to the usage scenario, such as designing the protective mask to be detachable. In normal use, the form of the protective mask mentioned in the background technology is adopted. When oxygen adjustment is needed, the protective mask in the normal state is removed and replaced with the protective mask in this application. Therefore, the structure of the safety helmet in the previous article is not overly limited here.

[0024] See also Figure 1-Figure 2In addition, in large mines, such as in long distance adit (horizontal or near horizontal tunnel) development of the form of the tunnel, due to the large size of the adit, the distance is long (2.5-6 kilometers), although the above safety helmet plans the optimal escape route, but for the miners near the mine exit, they actually do not need to perform the escape route, only need to leave after wearing the oxygen mask in the shortest distance; therefore, in the intelligent control method of the protective mask of the present application, the control module can intermittently collect the total length L of the mine (the reason for adopting intermittent is that in the mining process, the length of the tunnel form of the mine is gradually increasing), and instruct the front workers between the mine exit and the distance L / a from the mine exit to evacuate in the form of equal distance side by side, because the number of miners in large adit mines is large, even up to 200-500 people, therefore, the control module sets the miners between the mine exit and the distance L / a from the mine exit as front workers, and makes the front workers evacuate in the form of equal distance side by side, in the process of evacuation of the front workers, the safety helmet 2 of the front workers will feedback the detection values of the gas concentration sensors at each place in real time, the control module forms a gas concentration cloud chart according to these values, and connects the center points of the areas in the gas concentration cloud chart which are below the gas concentration threshold to form a second evacuation route for the middle and rear workers to evacuate; During this period, the control module instructs the middle and rear workers between the distance L / a from the mine exit and the distance L from the mine exit to evacuate along the first evacuation route designated by the safety helmet 2, when the middle and rear workers enter the front range, the control module instructs the middle and rear workers to evacuate along the second evacuation route, thereby greatly improving the accuracy of the evacuation route of the middle and rear workers; wherein a is a safety factor, which ensures that the front workers can safely evacuate without considering the gas concentration and oxygen concentration, and 2≤a≤3, when L is relatively small, such as 2.5≤L≤3.5, for example, when a=2, at this time, when the workers at the depth of L / 2 leave the mine, the workers at the depth of L will get the complete gas concentration cloud chart from the mine exit to the depth of L / 2, thereby helping them to evacuate quickly; when L is relatively large, such as 5≤L≤6, a=3 can be taken, thereby ensuring the safe evacuation of the front workers.

[0025] In addition, a display screen 1 is arranged on the cover 3 above the gas supply cover 4 in the protective mask, and a compass for guiding the workers is arranged on the display screen 1, therefore, in the control method in the present embodiment, the control module controls the direction of the compass through the first evacuation route and the second evacuation route to guide the middle and rear workers to walk along the first evacuation route and the second evacuation route, thereby ensuring the accuracy of the walking direction of the miners, wherein the compass can adopt the existing common technology, such as the guide mark in the map in the network, only needs to be able to guide the first evacuation route and the second evacuation route, which is not limited in this paper.

[0026] In the control method of the present invention, when the detection value of the gas concentration sensor is less than the gas concentration threshold and the real-time oxygen concentration Yi ≥ 19.5%, the control module controls the oxygen cylinder 6 to stop supplying oxygen. At this time, the miner can breathe outside air through the filter element 5 to achieve normal oxygen supply, thereby saving oxygen usage. In addition, the control module pre-inputs a second standard gas output volume C2 and an oxygen concentration threshold Y0 of the oxygen cylinder 6. When the detection value of the gas concentration sensor is less than the gas concentration threshold and the real-time oxygen concentration Yi < 19.5%, the control module controls the actual gas output volume Ci = bxC2xY0 / Yi of the oxygen cylinder 6 through C2, Y0, and Yi; b is a pre-input constant and Y0 < 19.5%. When the oxygen content decreases, the control module increases the gas output volume of the oxygen cylinder 6, thereby achieving a coordinated supply of oxygen to the miner by the oxygen cylinder 6 and the air. At this time, the actual gas output volume of the oxygen cylinder 6 is less than the first standard gas output volume, thereby further extending the service life of the oxygen cylinder 6 and ensuring the smooth evacuation of the miners.

[0027] It is worth mentioning that when miners are evacuated, their breathing will accelerate due to a lot of running in a short period of time, thereby increasing the oxygen consumption required by the human body. Therefore, in the present invention, a piezoelectric film respiratory rate sensor connected to the control module is provided inside the air supply hood 4 to measure the respiratory rate of the workers during the evacuation process. The control module upwardly corrects the gas output of the oxygen cylinder 6 when the respiratory rate increases, thereby ensuring sufficient oxygen supply to the miners and preventing hypoxia. Specifically, the standard respiratory rate H0 and the first standard oxygen output volume C1 are pre-entered into the control module. Therefore, when the detection value of the gas concentration sensor is greater than the gas concentration threshold, the control module determines the actual gas output volume Ci=cxC1xHi / H0 of the oxygen cylinder 6 based on H0, C1 and the actual respiratory rate Hi. c is a pre-entered constant. At this time, when the respiratory rate increases, the actual gas output volume of the oxygen cylinder 6 will also increase, thereby ensuring normal breathing of the miners. A standard respiratory rate H1 is pre-entered into the control module. When the detection value of the gas concentration sensor is less than the gas concentration threshold, the control module determines the actual gas output of the oxygen cylinder 6 using C2, Y0, Yi, H1, and Hi: Ci=dxC2xHi / H1+exC2x(Y0 / Yi), where d and e are pre-entered proportional coefficients and are both less than 1. A respiratory rate threshold H2 can be set. When Hi is less than H2, it indicates that the oxygen consumption has not increased much. At this time, the actual oxygen content in the outside air has a greater impact on the actual gas output of the oxygen cylinder 6. Therefore, d is less than e, and d=0.3 and e=0.7 are suitable. When Hi is greater than H2, it indicates that the oxygen consumption has increased significantly. At this time, the actual gas output of the oxygen cylinder 6 needs to be determined based on the actual oxygen consumption of the human body (i.e., respiratory rate). Therefore, d is greater than e, and d=0.8 and e=0.2 are suitable. This further realizes intelligent oxygen supply and ensures that the miners can evacuate smoothly.

[0028] It is worth mentioning that for the evacuation direction along the first or second evacuation route, the control module will group three consecutive center points into a group in sequence, thereby forming several path correction groups, and take the distance from the first center point to the second center point in each path correction group as D1, the distance from the first center point to the third center point as D2, and the distance from the second center point to the third center point as D3. If D1+D3≥2D2, there is a high probability that the oxygen consumption generated when passing through the first center point, the second center point and the third center point in sequence will be greater than the oxygen consumption generated when walking directly from the first center point to the third center point, and ... each path correction group will be greater than the oxygen consumption generated when walking directly from the first center point to the third center point, and the oxygen consumption generated when passing through the first center point, the second center point and the third center point in each path correction group will be greater than the oxygen consumption generated when walking directly from the first center point to the third center point, and the oxygen consumption generated when passing through the first center point, the second center point and the third center point in each path correction group will be greater than the oxygen consumption generated when walking directly from the first center point to the third center point, and the oxygen consumption generated when passing through the first center point, the second center The distance between the first center point, the second center point and the third center point must be greater than the distance from the first center point to the third center point. Therefore, since D1+D3≥2D2, if the evacuation is carried out according to the original route, the oxygen consumption will most likely increase and the distance will also increase. Therefore, it is necessary to correct the actual walking path of the path correction group at this time, that is, the control module corrects the second evacuation route connecting the three center points in the path correction group in sequence to the second evacuation route connecting the first center point and the third center point, thereby reducing the distance and having a greater probability of reducing oxygen consumption, thereby increasing the evacuation speed of the miners while preventing oxygen waste.

[0029] In addition, based on the above technical solution, for the second evacuation route, the control module further simulates and calculates the maximum inscribed circle radius R within the area of ​​the second center point in each path correction group based on the gas concentration cloud map. The center of the inscribed circle is the center point of the area. If D2 ≤ D1 + D3 - 2R, there is a greater probability that the oxygen consumption generated by passing through the first center point, the second center point, and the third center point in sequence will be greater than the oxygen consumption generated by walking directly from the first center point to the third center point. In this case, the control module corrects the second evacuation route connecting the three center points in sequence in the path correction group to a second evacuation route connecting the first center point and the third center point. In order to further accurately judge whether the path needs to be corrected, the standard inscribed circle radius R0 is pre-input into the control module, and the standard oxygen consumption required for the miner to walk out of the area with the standard inscribed circle radius R0 is taken as Q. When the miner walks with the output of the oxygen cylinder 6 as the first standard output, the distance the miner walks when the oxygen consumption reaches Q is q. q is pre-input into the control module, so when D2≤D1+D3-2R+fxqxR / R0 exists, the path is corrected. Here, the influence of the oxygen consumption in the second center point is taken into account, so the accuracy of whether the path needs to be corrected is further improved, thereby further improving the miner's evacuation speed while preventing oxygen waste, where f is a pre-input constant.

[0030] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "upper," "lower," "left," "right," "front," "rear," and similar expressions used herein are for illustrative purposes only.

[0031] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A protective mask based on a smart helmet, characterized in that: It includes a safety helmet, a cover body that transmits signals to the safety helmet through quick plug-in, and an oxygen cylinder connected to the air supply hood in the cover body. The air supply hood is connected to the outside world through a filter element, and a valve is provided between the filter element and the air supply hood. The safety helmet detects the gas concentration and oxygen concentration in the environment in real time, and the control module in the safety helmet controls the opening and closing of the valve and the gas output of the oxygen cylinder according to the gas concentration and oxygen concentration.

2. An intelligent control method for a protective mask, applied to the protective mask based on the smart helmet according to claim 1, characterized in that: A gas concentration threshold is pre-inputted into the control module; when the gas concentration is greater than the gas concentration threshold, the control module controls the valve to isolate the filter element from the gas supply hood, and controls the oxygen cylinder to output at the first standard gas output volume C1; when the gas concentration is less than the gas concentration threshold, the control module controls the valve to connect the filter element to the gas supply hood, and adjusts the gas output of the oxygen cylinder in real time according to the oxygen concentration.

3. The intelligent control method of the protective mask according to claim 2, characterized in that: The control module intermittently collects the total length L of the mine and instructs the front workers between the mine exit and the point L / a from the mine exit to evacuate in an equidistant and side-by-side manner, and instructs the middle and rear workers between the point L / a from the mine exit and the point L from the mine exit to evacuate along the first evacuation route designated by the safety helmet, where a is the safety factor; The control module forms a gas concentration cloud map based on the detection values ​​of the gas concentration sensor fed back by the front-end workers, and connects the center points of the areas below the gas concentration threshold in the gas concentration cloud map to form a second evacuation route for the middle and back-end workers to evacuate.

4. The intelligent control method of the protective mask according to claim 3, characterized in that: When the gas concentration is less than the gas concentration threshold and the real-time oxygen concentration Yi≥19.5%, the control module controls the oxygen cylinder to stop supplying oxygen.

5. The intelligent control method of the protective mask according to claim 3, characterized in that: The control module pre-inputs the second standard gas output volume C2 of the oxygen cylinder and the oxygen concentration threshold Y0. When the gas concentration is less than the gas concentration threshold and the real-time oxygen concentration Yi is less than 19.5%, the control module controls the actual gas output volume Ci=bxC2xY0 / Yi of the oxygen cylinder through C2, Y0 and Yi; b is a pre-input constant, and Y0<19.5%.

6. The intelligent control method of the protective mask according to claim 5, characterized in that: A piezoelectric film respiratory rate sensor connected to the control module is installed inside the air supply hood to measure the respiratory rate of workers during the evacuation process; the control module upwardly corrects the gas output of the oxygen cylinder when the respiratory rate increases.

7. The intelligent control method of the protective mask according to claim 6, characterized in that: The control module pre-inputs the standard breathing frequency H0 and the first standard oxygen output volume C1. When the gas concentration is greater than the gas concentration threshold, the control module determines the actual output volume of the oxygen cylinder Ci=cxC1xHi / H0 through H0, C1 and the actual breathing frequency Hi; c is a pre-input constant.

8. The intelligent control method of the protective mask according to claim 6, characterized in that: The standard breathing frequency H1 is pre-input into the control module. When the gas concentration is less than the gas concentration threshold, the control module determines the actual gas output of the oxygen cylinder Ci=dxC2xHi / H1+exC2x(Y0 / Yi) through C2, Y0, Yi, H1 and the actual breathing frequency Hi, where d and e are the pre-input proportional coefficients.

9. The intelligent control method of the protective mask according to claim 3, characterized in that: Along the evacuation direction of the second evacuation route, the control module will sequentially group three consecutive center points to form several path correction groups, and take the distance from the first center point to the second center point in each path correction group as D1, the distance from the first center point to the third center point as D2, and the distance from the second center point to the third center point as D3. If D1+D3≥2D2, the control module will correct the second evacuation route connecting the three center points in sequence in the path correction group to a second evacuation route connecting the first center point and the third center point.

10. The intelligent control method of the protective mask according to claim 9, characterized in that: The control module simulates and calculates the maximum inscribed circle radius R in the area of ​​the second center point in each path correction group based on the gas concentration cloud map. The center of the inscribed circle is the center point of the area. If D2≤D1+D3-2R+fxqxR / R0, the control module corrects the second evacuation route connecting the three center points in the path correction group in sequence to the second evacuation route connecting the first center point and the third center point; wherein, the standard oxygen consumption required for the miner to walk out of the area with the standard inscribed circle radius R0 is taken as Q. When the miner walks with the gas output of the oxygen cylinder as the first standard gas output, the distance the miner walks when the oxygen consumption reaches Q is q, and f is a pre-input constant.

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