CN102900469A - Safety monitoring method used for coal mine well - Google Patents

Abstract

The present invention relates to a safety monitoring method for underground coal mines, comprising the following steps: a. Set up a wireless sensor base station and a wireless sensor node at the monitored point, move the node relative to the base station, and set the coordinate points at different positions of the node relative to the base station , detect and record the signal strength of the current node received by the base station, build a signal strength and position coordinate mapping table, and store it in the base station; b. When the node is working, the base station obtains the node signal strength, and locates according to the signal strength and position coordinate mapping table The current position coordinates of the node; c. When it is judged that the current position coordinates of the node exceeds the set threshold, the base station sends an alarm message to the ground monitoring system. The present invention realizes position monitoring of wireless sensor nodes in coal mines at low cost, prevents violations of safety monitoring by placing sensor nodes in a safe environment, effectively eliminates potential safety hazards in coal mines, and prevents coal mines occurrence of security incidents.

Description

A safety monitoring method for coal mine underground

technical field

The invention relates to wireless sensor technology, in particular to a safety monitoring method for underground coal mines.

Background technique

Coal mine underground safety monitoring system has become an important means of coal mine safety management, production and equipment management. The coal mine safety monitoring system is mainly composed of sensors, sensor base stations, surface monitoring centers and transmission channels. The types of sensors commonly used in coal mines mainly include: environmental parameter sensors, production parameter sensors, equipment working conditions and fault protection sensors, and power sensors. The sensor is equivalent to the nerve endings of the safety monitoring system, responsible for measuring various parameters in the coal mine; other parts are responsible for the correct transmission and utilization of the parameters measured by the sensor. Therefore, it is the basis for the coal mine underground safety monitoring system to function normally that the sensor can obtain the correct measurement signal.

The signal measured by the sensor is transmitted to the ground monitoring center through the sensor base station in the coal mine. A sensor base station in the coal mine can be connected to one or more sensors. The sensor base station acts as a base station for communication between the sensor and the ground monitoring center. The sensor base station and Wired connections are used between the ground monitoring centers. Usually, the sensor base stations in coal mines are large in size and require special power supply for fixed installation, so they are not easy to move, while the sensors are small in size and flexible in power supply, so they are easy to install and easy to move. Therefore, some people take advantage of the movable characteristics of sensors to place sensor nodes in a safe environment, so that during daily monitoring, unreal coal mine underground information is transmitted to the ground monitoring center to avoid safety monitoring and conduct illegal operations.

Contents of the invention

In view of this, the object of the present invention is to propose a safety monitoring method for underground coal mines capable of positioning and monitoring wireless sensor nodes.

Safety monitoring method of the present invention comprises the following steps:

a. Set up a wireless sensor base station and a wireless sensor node at the monitored point, move the node relative to the base station, detect and record the signal strength of the current node received by the base station at different coordinate points of the node relative to the base station, and construct the signal strength and position The coordinate mapping table is stored in the base station;

b. When the node is working, the base station obtains the signal strength of the node, and locates the current position coordinates of the node according to the signal strength and position coordinate mapping table;

c. When it is judged that the current position coordinates of the node exceed the set threshold, the base station sends an alarm message to the ground monitoring system.

Based on the common wireless sensor transceiver device, the present invention applies the empirical model of converting wireless signal transmission loss into distance to the safety supervision system of the coal mine underground. The positioning function of the node in the system, when the node is moved so that its position coordinates relative to the base station exceeds the set threshold, the base station sends an alarm message to the ground monitoring system, preventing the evasion of security monitoring by placing the sensor node in a safe environment The illegal operation can effectively eliminate hidden safety hazards in coal mines and prevent the occurrence of safety accidents in coal mines, and the implementation of the safety monitoring method of the present invention does not require additional hardware facilities, and has good compatibility and low cost.

In the safety monitoring method for underground coal mines of the present invention, in the step b, the base station matches the position coordinates in the signal strength and position coordinate mapping table according to the minimum mean square error of the acquired signal strength as the current position coordinates of the node.

In the safety monitoring method for underground coal mines of the present invention, in the step a, the signal strength and position coordinate mapping table is constructed as follows:

According to the mathematical model between the signal strength value S and the relative distance d between the node and the base station: S=-(10n lg(d)+A)+45, calculate the current position coordinate point of the node, wherein, the A is the base station and the base station The absolute value of S when the nodes are 1 meter apart, and n is the wireless signal propagation index. Through the above steps, the signal strength and position coordinate mapping table of the present invention can be further refined. On the relative path between the node and the base station, a plurality of measurement points for measuring and recording the signal strength of the node can be taken, and the interval distance of each measurement point can be equal. The relative distance d between the node and the base station is quickly calculated through the above-mentioned mathematical model, so that the mapping table is more refined, so that the base station can more accurately locate the node when it is working.

In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: low-cost realization of the location monitoring of wireless sensor nodes in coal mines, preventing the evasion of safety monitoring by placing sensor nodes in a safe environment The illegal operation can effectively eliminate the potential safety hazards in coal mines and prevent the occurrence of safety accidents in coal mines.

Description of drawings

The present invention will be described by way of embodiment and with reference to accompanying drawing, wherein:

FIG. 1 is a schematic structural diagram of a wireless sensor node in the present invention.

Fig. 2 is a schematic structural diagram of the wireless sensor base station in the present invention.

Detailed ways

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification, unless specifically stated, can be replaced by other alternative features that are equivalent or have similar purposes. That is, unless stated otherwise, each feature is one example only of a series of equivalent or similar features.

Example

Referring to Fig. 1, the wireless sensor node in the present invention consists of MC9S12NE64 single-chip microcomputer (including processor and memory unit), Zigbee module CC2420E-M (including network and transceiver unit), gas sensor module (including sensor and digital-to-analog conversion unit) , power supply module and sound and light alarm module.

Referring to Fig. 2, the wireless transceiver module of the wireless sensor base station of the present invention is a Zigbee module CC2420E-M, and the wireless communication between the base station and the wireless sensor node is completed by this module; the controller is an integrated controller area network (ControllerArea Network, CAN) C85I F020 single-chip microcomputer, comprises processor and memory, realizes coordinate monitoring module function of the present invention by processor, writes the signal strength of wireless sensor node of the present invention and the position coordinate mapping table in memory; Wired communication module It is a CAN bus transceiver; the alarm module is an audible and visual alarm; it also includes a sensor module, that is, the base station can also sense and detect the surrounding environmental parameters. The wireless sensor base station is a node on the CAN bus system, and communicates with the ground monitoring center through a wired connection.

When the Zigbee module CC2420E-M of the base station correctly receives the signal strength value S of the current position of the node, it selects the ranging signal attenuation model of formula (1), converts the signal strength value S into a distance, and then constructs the node signal strength and position coordinates Mapping table:

S=-(10n l g(d)+A)+45 formula (1)

Wherein A is the absolute value of the RSS I when the base station and the node are 1 meter apart, and in this experiment, A ≈ 40 is measured, and n is the wireless signal propagation index, which is generally 2 to 4. In the present invention, the effect of 3.0 is obtained through repeated experiments. excellent.

In the present invention, both the wireless sensor base station and the nodes use short rod antennas, and the height of the base station is about 2m. Fix the base station, and gradually move the node relative to the base station. After a large number of experimental analysis, it is concluded that the signal strength value S of the node received by the base station changes significantly with the increase of the relative distance d between the node and the base station within the range of 30m. Therefore, the present invention The test range is limited to 0~30m. In the range of 0-30m, record the signal strength value S that the base station can receive at the current location of the node at intervals of 0.2m or 0.3m, and each location receives about 100 data packets, and the signal strength value S is averaged first , and then build a node signal strength and position coordinate mapping table based on formula (1), and write the mapping table into the memory of the C85IF020 microcontroller.

When the node is working, the base station takes the minimum mean square error of the acquired signal strength, and the position coordinates matched with the signal strength and position coordinate mapping table are the current position coordinates of the node, and the base station takes the minimum mean square error of the signal strength. Integrate the baseband IQ power within a time period (such as 104us) to obtain the instantaneous value S _i of the signal strength value S, that is, S _i = sum (I^2+Q^2); Taking n as 8192) S _i is averaged to obtain the average value S _average of the signal strength, that is, S _average = sumS _i /n, and at the same time, the maximum value of S _i within 1 second and S _i greater than a certain threshold K (K is The ratio of the arithmetic mean of n S _i ), that is, the number of S _i greater than K/n).

According to the obtained node signal strength, the current position coordinates of the node are located by the signal strength and position coordinate mapping table,

When it is judged that the current position coordinates of the node exceed the set threshold (according to the actual application environment, the set threshold in this embodiment is: the straight-line distance between the node and the base station is 5m), the base station sends an alarm message to the ground monitoring system to realize the prevention of safety monitoring Effective supervision of illegal operations.

The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, and any new method or process step or any new combination disclosed.

Claims (5)

1. a method for safety monitoring that is used under the coal mine is characterized in that, comprises the following steps:

A, at monitored some wireless senser base station, wireless sensor node are set, relatively described base station movement node, on the diverse location coordinate point of the relative base station of node, detect and record the signal strength signal intensity that the base station receives present node, make up signal strength signal intensity and position coordinates mapping table, and be stored in the base station;

B, when node is worked, the node signal intensity that the base station obtains is according to the current position coordinates of signal strength signal intensity and position coordinates mapping table location node;

C, when the decision node current position coordinates surpasses setting threshold, described base station earthward monitoring system sends a warning message.

2. as claimed in claim 1 for the method for safety monitoring under the coal mine, it is characterized in that, among the described step b, the base station is according to the Minimum Mean Square Error of the signal strength signal intensity obtained, with the position coordinates that mates in described signal strength signal intensity and the position coordinates mapping table be the current position coordinates of node.

3. as claimed in claim 1 or 2ly it is characterized in that for the method for safety monitoring under the coal mine, among the described step a, make up signal strength signal intensity and position coordinates mapping table and be:

According to the Mathematical Modeling between the relative distance d of signal strength values S and node and base station: S=-(10nlg (d)+A)+45, the current position coordinates point of computing node;

Wherein, described A is the absolute value of base station and node S in the time of 1 meter, and n is the radio signal propagation index.

4. be used for as claimed in claim 3 the method for safety monitoring under the coal mine, it is characterized in that, described A is that the span of 40, n is 2～4.

5. be used for as claimed in claim 4 the method for safety monitoring under the coal mine, it is characterized in that, described n is 3.0.

Images