How to deploy wireless sensor networks in challenging industrial environments. Wireless distributed sensor networks Sensor networks

Overview of modern wireless technologies

Sensor architecture

The touch sensor consists of hardware and software, like any other telecommunications node. AT general case sensor consists of the following

subsystems: perception, data processing, monitoring, communication and power supply (Figure 1.1).

Figure 1.1 - General architecture of the sensor.

The perception subsystem usually consists of an analog device that captures certain statistics and an analog-to-digital converter. The data processing subsystem contains a central processor and memory that allow storing not only data generated by the sensor, but also service information that is necessary for the correct and full functioning of the communication subsystem. The monitoring subsystem allows the sensor to collect environmental data such as humidity, temperature, pressure, magnetic field, air chemistry, etc. Also, the sensor can be supplemented with a gyroscope, an accelerometer, which makes it possible to build a positioning system.

Progress in the field wireless communication and microchip miniaturization open up new horizons in information and computer technologies. In addition to multi-hop networks, there are more complex routing protocols where the next node is selected based on an analysis of its characteristics, such as energy level, reliability, and the like. The situation becomes more complicated when the nodes of the wireless sensor network move - the network topology becomes dynamic.

To implement the sensor as a telecommunication device of small size (no more than one cubic centimeter), many technical aspects must be taken into account. The frequency of the central processor must be at least 20 MHz, the volume random access memory not less than 4 KB, transfer rate not less than 20 Kbps. Optimization of the hardware will reduce the size of the sensor, but will entail an increase in its price. operating system(OS) must be optimized for the architecture of the CPU being used. Limited resources and small memory size encourage the placement of the OS in ROM. Currently, the OS is widely used with open source Tiny OS, which allows you to control the sensors quite flexibly different manufacturers. In the field of networking, the limited power supply in the sensors imposes significant limitations on

the use of radio technologies that can be applied in sensor networks. It should also be noted that the limited performance of the central processor does not allow the use of standard routing protocols for IP networks.

– the high complexity of calculating the optimal path algorithm will overload the CPU. To date, a large number of special routing protocols for sensor networks have been developed.

The development of technology for data transmission in sensor networks is one of the most important tasks in building a sensor network, since its specific architectural and system characteristics impose a number of strict restrictions, among which the following should be emphasized:

Limited energy reserves, due to which the range is limited;

Limited processor performance;

Simultaneous operation of a large number of nodes in a limited space;

Equivalence of nodes, the client-server architecture is not applicable due to its characteristic delays;

Operation in the unlicensed frequency spectrum;

Low cost.

Currently, the development of sensor networks is based on the IEEE 802.15.4 Zigbee standard, which I mentioned above. In addition, I note that the Zigbee Alliance assumes that ZigBee radio access will be used in applications such as monitoring, factory automation, sensors, security, control, Appliances and much more. Thus, sensor network applications can be divided into several main categories:

Security, Emergencies and Military Operations;

Medicine and health;

Weather, environment and agriculture;

Factories, factories, houses, buildings;

Transport systems and vehicles.

I will consider cases of specific application of sensor networks in the above categories. Sensor networks can, at a minimum, be used in the following scenarios.

Application of sensor networks

Wireless sensor networks have unique characteristics of easy deployment, self-organization and fault tolerance. Emerging as a new information gathering paradigm, wireless sensor networks have been used for a wide range of purposes related to health, environmental monitoring, energy, food safety and production.

Over the past few years, there have been many prerequisites for sensor networks to become real. Several sensor node prototypes have been created, including Motes at Berkeley, uAMPS at MIT (at the Massachusetts Institute of Technology), and GNOMES at Rice. The elementary functions of sensor networks are positioning, detection, tracking, and detection. In addition to military applications, there have also been civilian applications based on elementary functions, which can be divided into environmental control, environmental monitoring, health care and other commercial

applications. In addition, Sibley recently created a mobile sensor called Robomote, which is equipped with wheels and is able to move around the field.

As one of the first attempts to use sensor networks for civil applications, Berkeley and Intel Research Laboratory used the Mote sensor network to monitor storm readings in the Great Duck Islands, Maine in the summer of 2002. Two-thirds of the sensors were installed off the coast of Maine to collect the necessary (useful) information in real time on the world wide web (Internet). The system worked for more than 4 months and supplied data

For 2 months after the scientists left the island due to bad weather conditions (in winter). This habitat monitoring application is an important class of sensor network applications. Most importantly, network sensors are able to collect information in dangerous environments that are unfavorable to people. In the course of monitoring studies, design criteria were considered, including design, creation, creation of a sensor system with the possibility of remote access and data management. Numerous attempts have been made to achieve the requirements, leading to the development of a set of prototype sensor network systems. The sensor system used by the Berkeley and Intel Research Laboratory, although primitive, was effective in collecting interesting environmental data and provided scientists with important information.

Sensor networks have found applications in the field of observation and prediction (guessing). A living example of such an application is the Automated Local Evaluation in Real-Time (ALERT) system developed by the National Weather Service with a wireless network of sensors. Equipped with meteorological/hydrological sensor devices, sensors in these conditions usually measure several properties of local weather, such as water level, temperature, wind. Data is transmitted via a direct radio transmission line (line-of-sight radio communication) through sensors on base station. The Flood Forecast Model has been adapted to process the data and issue automatic warnings. The system provides important information rainfall and water levels in real time to assess the possibility of potential flooding anywhere in the country. The present (current) ALERT system is installed throughout the US West Coast and is used for flood warning in California and Arizona.

Recently, sensor systems have been used extensively in the healthcare industry, used by patients and physicians to track and monitor glucose levels, cancer detectors, and even artificial organs. Scientists suggest the possibility of implanting biomedical sensors into the human body for various purposes. These sensors transmit information to an external computer system via a wireless interface. Several biomedical sensors are combined into a system of applications to determine the diagnosis and treatment of the disease. Biomedical sensors herald a more advanced level of medical care.

The main difference between wireless sensor networks and traditional computer and telephone networks is the absence of a permanent infrastructure that belongs to a particular operator or provider. Each user terminal in the sensor network has the ability to function not only as an end device, but also as a transit node, as shown in Figure 1.2.

Figure 1.2 - An example of connecting network sensors

Almost all spheres of life in the 21st century depend on information and communication technologies (ICT). Data is exchanged not only by people, but also by all kinds of intelligent systems, Cell phones, wearable devices, ATMs, sensors. At least 5 billion devices are already connected to the Internet of Things. The functioning of any large complexes - enterprises of industry, energy, agriculture, shopping centers, museums, offices, residential buildings - is associated with constant monitoring of the situation on their territory. Sensitive sensors in real time monitor the health of the equipment, the organization of the interaction of devices with each other, warn about the need to replace them or about emergencies. With rapidly growing volumes of data, an easy and convenient way to share them between devices and data centers is needed.

Print version:

Wireless sensor networks (WSNs, Wireless Sensor Networks), consisting of wireless sensors and control devices and capable of self-organization using intelligent algorithms, demonstrate large-scale prospects for monitoring human health, the state of the environment, the functioning of production and transport systems, accounting for various resources and others. This issue of the newsletter presents technological trends in the field of FSN related to the provision of permanent job wireless sensors and their application in two areas of the modern economy - advanced manufacturing and smart energy (smart grid).

Self-loading touch devices

For the development of wireless sensor networks, it is important to solve the problem of their power supply. A promising trend is the creation of durable offline devices with minimal energy consumption - converted from external sources.

Wireless touch devices can, for example, be powered by radio energy sent to them from a transmitter (like radio frequency identification (RFID) devices or contactless smart cards). This energy is used by the device both for recharging the sensor and for generating a response signal with information about the current state of the controlled object.

Another way is passive conversion of energy from the external environment (energy harvesting): solar (outside the premises in fairly clear weather), thermal energy, mechanical vibration energy (from devices working nearby - assembly machines, conveyors, etc.), vibration energy of the sensor itself (in the case of wearable devices), background radio emissions from surrounding electrical appliances (including Wi-Fi).

effects By reducing the highly toxic waste of spent power sources, the negative impact on the environment is reduced. The use of self-charging sensor devices will contribute to the development of wireless Internet of Things devices, personalized medicine (wearable and implantable devices that monitor human health indicators), as well as environmentally friendly technologies (green technologies) in energy, industry (especially in hazardous industries) and other areas .

Market estimates 30.1 billion By 2020, there will be 30.1 billion wireless devices in the world. The potential share of self-loading devices will reach 30-65%. The maximum manifestation of the trend is predicted in 2020–2030.

Drivers and barriers The relevance of the trend is constantly growing due to the miniaturization of wireless devices and reducing their cost. The development of the direction is hindered by the insufficient amount of energy in the current models of wireless sensors converted from the external environment, which is necessary to monitor the state of complex equipment and periodically send information to the data processing center.

Realization of advanced production based on wireless sensor networks

The irrational use of resources and production capacities, the generation of large amounts of polluting waste, the lack of constant monitoring of the state of facilities at enterprises - these and other problems of modern industry stimulate the transition to an advanced manufacturing model. It is characterized by the use of new materials and environmentally friendly technologies (green technologies), as well as the widespread use of ICT and intelligent systems, in particular robotics and wireless sensor networks.

Industrial wireless sensor networks (IBSS, Industrial Wireless Sensor Networks) - the most important factor in the implementation of advanced production. A set of interconnected wireless sensors and information systems, which process data from sensors and interact with controlled objects using control devices. Such automated system responds to any changes in indicators at the enterprise, notifies personnel about accidents and problem situations, analyzes the efficiency of equipment use, assesses the level of environmental pollution and the volume of waste generated.

effects The implementation of advanced production will increase the efficiency, accuracy and flexibility of process control at large enterprises and the quality of products, solve the issues of optimizing resources and identifying bottlenecks. Minimizing risks in production (due to greater automation) and reducing emissions will significantly reduce the industrial burden on the environment.

Market estimates $3.8 billion will reach the market size of industrial wireless sensor networks in 2017. The mass distribution of IBSS is predicted by 2017–2020.

Drivers and barriers The development of self-loading sensor devices, the transition to digital control of production equipment, the mass introduction of robotic systems stimulate the development of the trend. The lack of standardization of wireless sensor networks and the outdated ICT infrastructure in many industrial enterprises are slowing down the transition to an advanced manufacturing model.

"Smart" grids

The global problem of irrational use of electricity is especially relevant for Russia. High costs for electricity generation increase the cost of production, which places a double burden on the end consumer. To improve the efficiency and reliability of energy systems, many countries are moving towards the concept of "smart" energy networks (smart grid).

Such a network manages in real time all generating sources connected to it, main and distribution networks and objects that consume electricity. To manage the "smart" grid, wireless sensor networks are used that control the volume of energy production and energy consumption in its different sections. With the help of information systems, the optimal distribution of energy in the network is calculated, forecasts are made for different seasons and periods of the day, energy generation and its delivery are synchronized, and the safety of power lines is monitored. To increase the efficiency of the power grid, its non-critical elements are turned off for the period of reduced activity.

effects Continuous monitoring and control of devices in the power system reduces power outages. Significant cost savings in its production leads to positive effects for industry, the social sphere and the environment (now in Russia the share of energy in air pollution is 26.8% - the maximum value in comparison with other areas).

Market estimates $63 billion by 2020 will be the size of the global market for smart grid technologies with an average annual growth rate of more than 8%. 2018–2025 - the period of maximum manifestation of the trend.

Drivers and barriers The introduction of more stringent environmental regulations and standards is accelerating the trend. The right moment for the introduction of smart grid in Russia is the planned renewal of the infrastructure facilities of the electric power industry. The transition to the smart grid concept is complicated by the large scale of the industry, the high cost and significant time spent on its technological renewal. Periodic shutdowns of power plants during the modernization of power grids are a problem for consumer companies.

Monitoring of global technological trends is carried out by the Institute for Statistical Research and Economics of Knowledge of the Higher School of Economics () as part of the Program fundamental research NRU HSE.

The following sources were used in preparing the trendletter: Forecast of scientific and technological development of the Russian Federation until 2030(prognoz2030.hse.ru), materials scientific journal "Foresight"(foresight-journal.hse.ru), data web of science, Orbit, idc.com, marketsandmarkets.com, wintergreenresearch.com, greentechmedia.com, greenpatrol.ru, etc.

History and scope

One of the first prototypes of the sensor network can be considered the SOSUS system, designed to detect and identify submarines. Technologies of wireless sensor networks began to develop actively relatively recently - in the mid-1990s. However, only at the beginning of the 21st century, the development of microelectronics made it possible to produce a fairly cheap element base for such devices. Modern wireless networks are mainly based on the ZigBee standard. A considerable number of industries and market segments (manufacturing, various modes of transport, life support, security) are ready for the implementation of sensor networks, and this number is constantly increasing. The trend is driven by increasing complexity technological processes, the development of production, the expanding needs of individuals in the segments of security, resource control and the use of inventory. With the development of semiconductor technologies, new practical tasks and theoretical problems appear related to the applications of sensor networks in industry, housing and communal services, and households. The use of low-cost wireless sensor control devices opens up new areas for the application of telemetry and control systems, such as:

• Timely detection of possible failures of actuators, to control such parameters as vibration, temperature, pressure, etc.;
• Real-time access control to remote systems of the monitored object;
• Automation of inspection and maintenance of industrial assets;
• Commercial asset management;
• Application as components in energy and resource saving technologies;
• Control of eco-parameters of the environment.

It should be noted that despite the long history of sensor networks, the concept of building a sensor network has not finally taken shape and has not been expressed in certain software and hardware (platform) solutions. The implementation of sensor networks at the current stage largely depends on the specific requirements of the industrial task. The architecture, software and hardware implementation is at the stage of intensive technology formation, which draws the attention of developers in order to search for a technological niche for future manufacturers.

Technology

Wireless sensor networks (WSNs) are made up of miniature computing devices- motors equipped with sensors (sensors for temperature, pressure, light, vibration level, location, etc.) and signal transceivers operating in a given radio range. Flexible architecture, reduced installation costs distinguish wireless smart sensor networks from other wireless and wired data interfaces, especially when it comes to in large numbers connected devices, the sensor network allows you to connect up to 65,000 devices. The constant reduction in the cost of wireless solutions, the increase in their operational parameters make it possible to gradually reorient from wired solutions in systems for collecting telemetry data, remote diagnostics, and information exchange. "Sensory network" is a well-established term today. Sensor Networks), denoting a distributed, self-organizing, fault-tolerant network of individual elements from unattended and requiring no special installation of devices. Each sensor network node can contain various sensors for environmental control, microcomputer and radio transceiver. This allows the device to take measurements, independently carry out initial data processing and maintain communication with an external information system.

802.15.4/ZigBee relayed short-range radio technology, known as "Sensor Networks" (eng. WSN - Wireless Sensor Network), is one of the modern directions in the development of self-organizing fault-tolerant distributed systems for monitoring and managing resources and processes. Today, wireless sensor network technology is the only wireless technology, with which you can solve the tasks of monitoring and control, which are critical to the operation time of sensors. The sensors combined into a wireless sensor network form a territorially distributed self-organizing system for collecting, processing and transmitting information. The main area of ​​application is the control and monitoring of the measured parameters of physical media and objects.

• radio path;
• processor module;
• battery;
• various sensors.

A typical node can be represented by three types of devices:

• Network coordinator (FFD - Fully Function Device);
  • performs global coordination, organization and setting of network parameters;
  • the most complex of the three device types, requiring the most memory and power supply;

• Device with a full set of functions (FFD - Fully Function Device);
  • support for 802.15.4;
  • additional memory and power consumption allows you to act as a network coordinator;
  • support for all types of topologies ("point-to-point", "star", "tree", "mesh network");
  • the ability to act as a network coordinator;
  • the ability to access other devices on the network;
• (RFD - Reduced Function Device);
  • supports a limited set of 802.15.4 features;
  • support for point-to-point, star topologies;
  • does not act as a coordinator;
  • calls the network coordinator and router;

Companies developers

There are different types of companies on the market:

Notes

Wikimedia Foundation. 2010 .

See what "Wireless Sensor Networks" is in other dictionaries:

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The advantages of wireless sensor networks technologies can be effectively used to solve various applied problems related to the distributed collection, analysis and transmission of information.

Building automation

In some building automation applications, the use of traditional wired communication systems is not feasible for economic reasons.

For example, you need to introduce a new or expand existing system in a used building. In this case, the use of wireless solutions is the most acceptable option, because. no additional installation work is required with a violation of the interior decoration of the premises, practically no inconvenience is caused to employees or residents of the building, etc. As a result, the cost of implementing the system is significantly reduced.

Another example would be open-plan office buildings for which it is not possible to specify the exact locations of sensors at the design and construction stage. At the same time, the layout of offices can change many times during the operation of the building, therefore, the time and cost spent on reconfiguring the system should be minimal, which can be achieved by using wireless solutions.

In addition, the following examples of systems based on wireless sensor networks can be given:

• monitoring of temperature, airflow, presence of people and control of heating, ventilation and air conditioning equipment in order to maintain the microclimate;
• lighting control;
• energy management;
• collection of readings from apartment meters for gas, water, electricity, etc.;
• monitoring of the state of load-bearing structures of buildings and structures.

industrial automation

Until now, the widespread use of wireless communication in the field of industrial automation has been constrained by the low reliability of radio channels compared to wired connections in harsh industrial environments, but wireless sensor networks are fundamentally changing the current situation, because inherently resistant to various kinds of disturbances (for example, physical damage to the node, the appearance of interference, changing obstacles, etc.). Moreover, under some conditions, a wireless sensor network can provide even greater reliability than a wired communication system.

Solutions based on wireless sensor networks fully meet the requirements of the industry:

• fault tolerance;
• scalability;
• adaptability to operating conditions;
• energy efficiency;
• taking into account the specifics of the applied task;
• economic profitability.

Wireless sensor network technologies can be used in the following industrial automation tasks:

• remote control and diagnostics of industrial equipment;
• maintenance of equipment according to the current state (prediction of the safety margin);
• monitoring of production processes;
• telemetry for research and testing.

Other applications

The unique features and differences of wireless sensor networks from traditional wired and wireless data transmission systems make their application effective in a wide variety of areas. For example:

• security and defense:
  • control over the movement of people and equipment;
  • means of operational communications and intelligence;
  • perimeter control and remote monitoring;
  • assistance in rescue operations;
  • monitoring of property and valuables;
  • security and fire alarm;
• environmental monitoring:
  • pollution monitoring;
  • Agriculture;
• healthcare:
  • monitoring the physiological state of patients;
  • location control and notification of medical personnel.