Download Research of a Mine Safety Monitoring System Based on WSN LEI Wenli

Physical and Numerical Simulation of Geotechnical Engineering
21st Issue, Dec. 2015
Research of a Mine Safety Monitoring System Based on
WSN
LEI Wenli 1, REN Xincheng 1, ZHANG Yang 2
1. College of Physic and Electronic Information, Yan’an University, Yan’an 716000, China
2. China Coal Research Institute, Beijing 100013, China
ABSTRACT: This paper presents a mine safety monitoring system based on WSN network, which
collects mine tunnel environmental parameter data through a tunnel environmental data collection
node, and sending the collected environment parameter data to the ground monitoring center
computer by WSN network. The monitoring center computer can view the tunnel production
environmental information in real time combined with the geographic mine information, in order to
ensure mine production safety and provide a reliable basis for accident recovery. Tunnel
environmental data collection node is developed based on embedded system platform ARM7 which
has low power consumption and high reliability. Simulated tunnel test experiments show that the
system is stable, and it provides a reliable real-time early warning and rescue information for the
safety of mine production.
KEYWORDS: WSN, Mine safety, Monitoring, Accident rescue
environments.
1 INTRODUCTION
Frequent mine accidences have become the social focus.
At the same time, with the rapid development of wireless
communication technology and embedded technology, the
application of intelligent, automated monitoring system to
monitor the coal mine production environment and ensure
the mine safety has become an integral part of digital mines.
This paper puts forward a mine safety monitoring system
based on WSN network, which collects mine tunnel
environmental parameter data through a tunnel
environmental data sampling node, and sends the collected
environment parameter data to the ground monitoring
center computer. The monitoring center computer can view
the tunnel production environmental information in real
time combined with the geographic mine information,
which provides a reliable basis for mine production safety
and accident rescue.
2 WSN NETWORK TECHNOLOGY
WSN (Wireless Sensor Network) is a system formed
through self-organization network connection of many
microsensor nodes which have self-organizing capability.
The microsensor nodes have main control chips, which can
collect and process the parameter information in network
coverage areas, and send out the parameter data through
multi-hop. According to different sensors in WSN, WSN
can measure various parameter data, including temperature,
humidity, light, noise, pressure, water quality composition
and gas composition, etc. WSN can be applied in different
environments; the hardware and software platforms of
WSN in turn are different because of different
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3 DESIGN OF MINE SAFETY MONITORING
SYSTEM
Mine safety monitoring system is divided into data
acquisition of tunnel environment, routing transmission and
ground monitoring [4-6], as known in Figure 1. Data
acquisition of tunnel environment is composed of
environmental data sampling nodes with temperature,
humidity and gas sensor, which is placed in the tunnel
randomly or artificially. It is responsible for the
underground mine tunnel environmental data collection.
Routing transmission is composed of routing nodes and
aggregation nodes. Routing nodes are fixed on the supports
or equipment in the tunnel every 20~100 meters, according
to tunnel communication environment of the production
site. Its main task is conveying the tunnel environmental
data collected by tunnel environmental data sampling nodes
to aggregation nodes through multi-hop. Aggregation nodes
are the gateway nodes between sampling nodes of tunnel
environmental data and ground monitoring, which connect
ground monitoring computer by wire or wireless means,
and the data of routing nodes to ground monitoring center.
Ground monitoring computer can view the environmental
information in real time, such as temperature, humidity and
gas density of mine production field, on the basis of tunnel
environmental data, combined with the geographic mine
information. It provides a reliable basis for mine
production safety and accident rescue. The core of mine
safety monitoring system is tunnel environmental data
collection, which will influence the authenticity and
reliability.
Research of a Mine Safety Monitoring System Based on WSN
DOI: 10.5503/J.PNSGE.2015.21.013
Figure 1 System composition
nodes includes main control processor module, wireless
transceiver module [7-8], storage unit, power supply module,
clock circuit, sensor module and a control circuit, as shown
in Figure 2.
4
HARDWARE
DESIGN
OF
TUNNEL
ENVIRONMENTAL DATA SAMPLING NODE
Hardware of mine tunnel environmental data sample
Figure 2 Hardware block diagram
Main control processor module, which works under the
environment of much flammable and explosive gas, such as
gas in mine tunnel, can run under low power consumption;
the chip should possesses ADC in order to receive analog
signals collected by various sensors; it should also have
strong ability of data handling capacity. After comparison
of ARM, OMAP and other main processors, ARM7
S3C44B0 microsensor by Samsung Company has been
chosen. ARM7 S3C44B0 microsensor, which adopts
ARM7TDMI microprocessor core [9], has relatively rich
peripheral interface, strong expansion capacity, and higher
price performance. It is suitable to be used as a main
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Physical and Numerical Simulation of Geotechnical Engineering
21st Issue, Dec. 2015
control processor of the mine tunnel data sampling node.
Wireless receiving and dispatching module should
support ZigBee to achieve low power communications and
facilitate the formation of WSN network. The Nrf2401
transceiver chip is chosen, which works in ISM frequency
band (2.4 ~ 2.5 GHz). The chip includes crystal oscillator,
frequency synthesizer, power amplifier and modulator,
which connects with ARM7 S3C44B0 main control chip
through SPI bus. Its work parameter, such as output power,
frequency of communications can be configured through
3-wire SPI, which has the characteristics of low power
consumption, duplex communications and wide range of
application.
Storage unit is composed of SDRAM storage and
FLASH storage. SDRAM storage is used to store operation
system. FLASH storage is used to store mine tunnel
environmental data.
The tunnel environmental parameter sampling sensor
module is composed of temperature sensor, humidity sensor
and gas density sensor. The temperature sensor and
humidity sensor adopt DSl8B20 chip and HIH4000 chip,
whose external connection interface are simple, volume are
small. It is easy to carry under the mine. Gas density sensor
adopts MH-440D infrared gas sensor, which applies
non-dispersive infrared (NDIR) principle to detect the
existence of CH4 in the air. It has good selectivity, no
oxygen dependence, stable performance and long life with
a complete function of gas detection, analog voltage signal
output and serial communications.
Power module is composed of two 5V dry cells,
AMSl117-3.3 Variable voltage chip, AMSl117-1.8 Variable
voltage chip and power supply circuit. It can supply power
respectively to chips on board, peripheral chips, and main
control chip with voltage of 3.3 V and 1.8 V.
cut-back and portability. In the process of application
program development based on the uClinux operation
system, almost all the Linux API function can be used,
which will greatly reduce the difficulty and shorten the
cycle of system development.
5.1 System Transplantation
Boot loader is a small segment of boot code, which starts
from initial address on hardware system before the uClinux
operation system is called. It is in charge of basic hardware
equipment in initialization and memory mapping, which
loads the embedded uClinux operation system and file
system from FLASH storage to RAM; Boot loader can
online-update operation and file systems under command
line. It can also wipe and modify the physical address space
directly. Tunnel environmental sampling nodes adopt Blob
as the boot loader, which is stable and mature.
The kernel version of uClinux transplantation is
Linux2.4 kernel. The porting configurations adopt graphic
interface. The support of ARM7 processor in the kernel
should be pointed out. The compiling of the arm-elf-gcc
cross-compiler tool chain for the start of ARM platform is
shown as follows.
$> make menuconfig
$> make dep
$> make zImage
The uClinux kernel image file of ELF format after
compiling can be programmed to FLASH storage through
serial interface or network interface. The file system of
tunnel environmental data sampling nodes is romfs file
system.
5.2 Application Program Development
The application of tunnel environmental data sampling
nodes is in charge of collection and transmission of tunnel
environmental parameter data and the reception of
commands from ground monitoring center computer. The
application includes the tasks of temperature data collection,
humidity data collection and gas density data collection.
After the operation of system, hardware equipment should
be initialized and operation system software should be
started. When tunnel environmental data sampling nodes
receive commands of data collection, tasks of
environmental data collection should be started. When the
tasks are finished, the data are sent to routing nodes. The
routing nodes will convey the parameters of temperature,
humidity and gas density collected by sampling nodes to
aggregation nodes through multi-hop. Then aggregation
nodes will send the data to ground monitoring center
computer. When there is no command of data collection,
the system will hang the collection tasks, i.e. starting the
power-saving tasks and entering the power-saving mode.
The process of the software is shown in Figure 3.
5 SOFTWARE DESIGN
The software of tunnel environmental data sampling
nodes runs on hardware platform, with the function of
tunnel environmental data collection. It is composed of the
underlying operating system and tunnel environmental data
collection application program. The operating system
consists of hardware drivers which supplies interface
function for writing of environmental data collection
programs. The operation system of tunnel environmental
data sampling nodes adopts embedded uClinux system. The
system consists of boot loader, uCLinux kernel image file
and file system [10].
The uClinux is a lightweight embedded Linux version,
which is specifically aimed at the CPU without MMU
(memory management unit). It follows the GNU License,
which has good network performance, complete file
support system, high reliability, and the property of
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Research of a Mine Safety Monitoring System Based on WSN
DOI: 10.5503/J.PNSGE.2015.21.013
Figure 3 The software flow chart of the mine tunnel environmental data collection node
temperature and humidity parameter data are actually
measured in four periods under simulated tunnel
environment. The test data are compared with the actual
data. The test data under simulated tunnel environment are
listed as follows in Table 1.
6 TEST RESULTS
The tunnel environmental data sampling nodes operate
stably after module test and integration test. The tunnel
Table 1 Tunnel temperature and humidity environment parameter data
Humidity Test
Values (RH%)
Humidity Actual
Values (RH%)
Error Values
(%)
Temperature
Test Values (℃)
Temperature
Actual Values (℃)
Error
Values (℃)
1
48.3%
50.1%
-1.8
15.0
14.8
0.2
2
49.5%
50.2%
-0.7
18.5
18.9
-0.4
3
46.1%
48.1%
-2.0
21.0
21.0
0
4
47.0%
49.1%
-2.1
17.1
17.4
-0.3
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Physical and Numerical Simulation of Geotechnical Engineering
21st Issue, Dec. 2015
The test result shows that the statistical errors of the
temperature and humidity parameter data collected by
tunnel environmental data sampling nodes are small. The
ground monitoring center computer can view the tunnel
production environmental information in real time through
WSN network. The collection, transmission and reception
of the system data are stable, which provides a reliable
real-time early warning and rescue information for the
safety of mine production.
2. REN Xincheng (19667- ), male, professor, main
research:
electronic
information
technology,
communication system design. Physics and Electronic
Information College of Yan’an University, 716000.
3. ZHANG Yang (1984- ), male, master, main research:
coal mine safety.
7 CONCLUSION
[1].
BIBLIOGRAPHY
YUAN Shenfang, QI Lei, TONG Yao, ZHANG Bingliang,
GAO Shang. FPAA Based Self-repairing Wireless Sensor
Network Node [J]. Chinese Journal of Scientific Instrument.
2012, 33 (7): 1588-1593
[2]. LI Weibin. Research of Mine Environment and Personnel
Monitoring System Based on Wireless Sensor Networks [D].
Xi'an: Chang'an University. 2009: 5-11
[3]. WANG Ji, XU Guobao, SHEN Yuli. Sea Water Heavy Metal
Monitor System Based on Wireless Sensor Network [J].
Computer Measurement & Control. 2009. 04: 643-645
[4]. PENG Yu, WANG Dan. A Review: Wireless Sensor
Networks Localization [J]. Journal of Electronic
Measurement and Instrument. 2011, 25 (5): 389-399
[5]. ZHANG Qianqian, ZHANG Yikui, PAN Yong. Kind of
Fusion Protocol Node Design Based on Internet of Things
[J]. Electronic Measurement Technology. 2011, 34 (8):
85-87
[6]. MU Naigang. Introduction of ZigBee Technology [J].
Telecommunications Technology. 2006. 3: 84-86
[7]. NIU Haijun, FAN Yubo, YANG Songyan, LI Lifeng, LI
Deyu. Design of An Ultrasound Bladder Volume
Measurement and Alarm System Based on ARM and DSP
[J]. Chinese Journal of Scientific Instrument. 2011, 32 (8):
1858-1863
[8]. SUN Yi. ARM-Linux Embedded System Development
Foundation [M]. Xi'an: Xidian University Press. 2008.08
[9]. ZHANG Ru, SUN Songlin, YU Xiaogang. Embedded
Systems Technical Foundation [M]. Beijing: Beijing Posts
and Telecommunications University Press. 2006. 01
[10]. LIU Miao. Design of Embedded System Interface and Linux
Driver Development [M]. Beijing: Beijing Aerospace
University Press. 2006. 5
(1) A tunnel safety monitoring system is developed,
which is based on the WSN network. It describes in detail
the hardware architecture of tunnel environmental data
sampling nodes, the select of hardware chip, and the ways
of connection. It also explains the implementation
processes of the software platform and application
program.
(2) The low power consumption of main control chip
ARM7 processor is suitable to run under the underground
environment. Test results show that through WSN network,
mine safety monitoring system can view the tunnel
production environment data in real time. The collection,
transmission and reception of the system data are stable,
which provides a reliable real-time early warning and
rescue information for the safety of mine production. Later
paper aims at collecting the data of methane concentrations
under tunnel environment and further verifying the
performance of the system.
FUND PROGRAM
Natural Science Foundation of Shannxi Province
(2012JK0439), Science and Technology Projects of Yan’an
(2011kg-22), Natural Science Foundation of Yan’an
University
(YD2012-04),
High-level
university
construction Special Foundation of Shannxi Province
(Physics- 2012SXTS05).
AUTHORS
1. LEI Wenli (1982- ), male, lecturer, main research:
embedded system. Physics and Electronic Information
College of Yan’an University, 716000.
Email: [email protected]
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