A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

A Structured Hardware/Software Architecture for Embedded Sensor Nodes

Owing to the limited requirement for sensor processing in early networked sensor nodes, embedded software was generally built around the communication stack. Modern sensor nodes have evolved to contain significant on-board functionality in addition to communications, including sensor processing, energy management, actuation and locationing. The embedded software for this functionality, however, is often implemented in the application layer of the communications stack, resulting in an unstructured, top-heavy and complex stack. In this paper, we propose an embedded system architecture to formally specify multiple interfaces on a sensor node. This architecture differs from existing solutions by providing a sensor node with multiple stacks (each stack implements a separate node function), all linked by a shared application layer. This establishes a structured platform for the formal design, specification and implementation of modern sensor and wireless sensor nodes. We describe a practical prototype of an intelligent sensing, energy-aware, sensor node that has been developed using this architecture, implementing stacks for communications, sensing and energy management. The structure and operation of the intelligent sensing and energy management stacks are described in detail. The proposed architecture promotes structured and modular design, allowing for efficient code reuse and being suitable for future generations of sensor nodes featuring interchangeable components

Electrode and Electrolyte Design to Develop Advanced Battery Technologies for Large Scale Energy Storage

Large-scale energy storage devices play a key role in regulating the renewable energy to build a carbon-free sustainable future, but the widely used lithium-ion batteries cannot meet the demands because of the limited lithium resource and high cost. Thus, it is urgent to develop next-generation battery technologies with low cost and high safety. Sodium-ion battery is considered as a promising candidate due to the abundant sodium resources and low cost. Its practical application, however, is hindered by the absence of the advanced electrode materials. The tin-based anodes deliver high theoretical capacities and show great promise for the sodium-ion batteries, but the large volume expansion upon cycling can damage the structure and lead to short cycling life. In this dissertation, three tin-base anodes have been developed. First, a free-standing Sn@CFC electrode was synthesized via the electrospinning method. The carbon fiber and Sn nanoparticles together provide fast ions and electrons pathway, enabling a dominant pseudocapacitance contribution. Moreover, the facile manufacturing technique yields the Sn@CFC electrode with a high mass loading. Second, a novel anode was designed with a pomegranate-like structure that the SnP2O7 nanoparticles dispersed in the robust N-doped carbon matrix. The carbon matrix forms strong interaction with the SnP2O7 nanoparticles, leading to a stable structure without any particle aggregation. Third, a SnS/Sb2S3 heterostructure was prepared and encapsulated in the sulfur and nitrogen co-doped carbon matrix with engineered porous structure. The porous structure can provide void space to alleviate the volume expansion upon cycling, guaranteeing excellent structural stability. The unique heterostructure and the S, N co-doped carbon matrix together facilitate fast-charge transport to improve reaction kinetics. Aqueous zinc-ion batteries show great promise in large-scale energy storage. However, the decomposition of water molecules leads to severe side reactions, resulting in the limited lifespan of the zinc-ion batteries. Here, the tetrahydrofuran additive was introduced into the zinc sulfate electrolyte to reduce the water activity by modulating the solvation structure of the Zn hydration layer. Thus, in an optimal 2 M ZnSO4/THF (5% by volume) electrolyte, the hydrogen evolution reaction and byproduct precipitation can be suppressed, which greatly improves the cycling stability and Coulombic efficiency

A Novel Battery Management & Charging Solution for Autonomous UAV Systems

abstract: Currently, one of the biggest limiting factors for long-term deployment of autonomous systems is the power constraints of a platform. In particular, for aerial robots such as unmanned aerial vehicles (UAVs), the energy resource is the main driver of mission planning and operation definitions, as everything revolved around flight time. The focus of this work is to develop a new method of energy storage and charging for autonomous UAV systems, for use during long-term deployments in a constrained environment. We developed a charging solution that allows pre-equipped UAV system to land on top of designated charging pads and rapidly replenish their battery reserves, using a contact charging point. This system is designed to work with all types of rechargeable batteries, focusing on Lithium Polymer (LiPo) packs, that incorporate a battery management system for increased reliability. The project also explores optimization methods for fleets of UAV systems, to increase charging efficiency and extend battery lifespans. Each component of this project was first designed and tested in computer simulation. Following positive feedback and results, prototypes for each part of this system were developed and rigorously tested. Results show that the contact charging method is able to charge LiPo batteries at a 1-C rate, which is the industry standard rate, maintaining the same safety and efficiency standards as modern day direct connection chargers. Control software for these base stations was also created, to be integrated with a fleet management system, and optimizes UAV charge levels and distribution to extend LiPo battery lifetimes while still meeting expected mission demand. Each component of this project (hardware/software) was designed for manufacturing and implementation using industry standard tools, making it ideal for large-scale implementations. This system has been successfully tested with a fleet of UAV systems at Arizona State University, and is currently being integrated into an Arizona smart city environment for deployment.Dissertation/ThesisMasters Thesis Computer Engineering 201

Sustainability Assessment of Wireless Community Grid for Off-Grid Communities: A Case Study for Haiti

Affordable, reliable, and sustainable energy service is fundamental to human, social and economic development. Approximately 1.2 billion people lack access to basic energy services. There exists a huge energy access gap between urban centers and rural areas. Approximately 84% of the people deprived of energy access live in rural areas. Existing rural electrification options including grid extension, mini-grids, and stand-alone solar home systems, have limited penetration in rural regions. Entrepreneurs, with support from governments and international institutions, have experimented with different business mechanisms to facilitate energy delivery. A significant amount of investment is being made for rural electrification but many projects are not self-sustaining. This research develops a new approach, ‘Wireless Community Grid’, to provide basic energy services to rural households and evaluates if the approach meets the desired features of affordability, profitability, and scalability. The approach comprises of a central charging station operated by local vendors, where portable power systems are charged and rented to homeowners. Each portable power system provides power to each home in the form of indoor lighting and device charging. Each power system is swapped from the station at a regular interval. To understand the energy needs and expenses of a rural population, surveys were conducted in Borgne, Haiti. The major sources for lighting are kerosene lamps, rechargeable bulbs and candles. For charging lights and phones, people have to walk to a vendor with solar systems or generators. Based on three surveyed communities, each household typically spends $2.50 a week on energy services and local vendors make$0.70 a week from each household served. To explore the sustainability of the Wireless Community Grid approach, three preliminary evaluation models were developed. First, a techno-economic tool was used to evaluate the relationship between reliability and cost. Based on the developed tool, a system consisting of 350 W solar array and 58 portable power units with 283 Wh capacity would meet the basic energy needs of a community of 49 households at the lowest present value. Second, a life cycle assessment was performed to study the environmental impacts. It was observed that the proposed system would provide a yearly reduction of 382 kg of CO2 equivalents and 197 kg of crude oil equivalents for each household served compared to the current energy state. Finally, a social business structure was proposed to maximize the number of people impacted while keeping the system affordable and self-sustainable. While keeping the household energy cost level at $2.50/week for energy services, the capital investment of$6100 for a community system, could be recovered in less than 2 years. Over 10 years, the returns on a single investment would be able to expand to 64 similar communities and provide energy services to around 19,000 people. The wireless community grid approach appears to be affordable for end-users and provides profits for local vendors while being financially and environmentally sustainable and highly scalable

Solar energy harvesting and software enhancements for autonomous wireless smart sensor networks

Civil infrastructure is the backbone of modern society, and maintaining said infrastructure is critical in maintaining healthy society. Wireless smart sensors (WSSs) provide a means to effectively monitor the performance of buildings and bridges to improve maintenance practices, minimize the costs of repair, and improve public safety through a process called structural health monitoring (SHM). WSSs, traditionally powered by batteries, are limited in the length of time they can operate autonomously. The frequent need to change batteries in the networks can drive up maintenance costs and diminish the advantage first realized with WSSs. Efforts have been made to minimize the power consumption of WSSs operating in SHM networks, but there have been a limited number of new power supply options, such as energy harvesting, used in full-scale SHM applications. This research develops a solar energy harvesting system to provide power to Imote2 WSS platform and increase the long-term autonomy of wireless smart sensor networks (WSSNs). The approach is validated on a cable stayed bridge in South Korea. Additionally, software enhancements are introduced to allow sensor data to be stored in non-volatile memory, potentially further enhancing the efficacy of WSSNs. This research has resulted in greater overall autonomy of WSSNs

Design and Field Test of a WSN Platform Prototype for Long-Term Environmental Monitoring

Long-term wildfire monitoring using distributed in situ temperature sensors is an accurate, yet demanding environmental monitoring application, which requires long-life, low-maintenance, low-cost sensors and a simple, fast, error-proof deployment procedure. We present in this paper the most important design considerations and optimizations of all elements of a low-cost WSN platform prototype for long-term, low-maintenance pervasive wildfire monitoring, its preparation for a nearly three-month field test, the analysis of the causes of failure during the test and the lessons learned for platform improvement. The main components of the total cost of the platform (nodes, deployment and maintenance) are carefully analyzed and optimized for this application. The gateways are designed to operate with resources that are generally used for sensor nodes, while the requirements and cost of the sensor nodes are significantly lower. We define and test in simulation and in the field experiment a simple, but effective communication protocol for this application. It helps to lower the cost of the nodes and field deployment procedure, while extending the theoretical lifetime of the sensor nodes to over 16 years on a single 1 Ah lithium battery

Energy harvesting towards self-powered iot devices

The internet of things (IoT) manages a large infrastructure of web-enabled smart devices, small devices that use embedded systems, such as processors, sensors, and communication hardware to collect, send, and elaborate on data acquired from their environment. Thus, from a practical point of view, such devices are composed of power-efficient storage, scalable, and lightweight nodes needing power and batteries to operate. From the above reason, it appears clear that energy harvesting plays an important role in increasing the efficiency and lifetime of IoT devices. Moreover, from acquiring energy by the surrounding operational environment, energy harvesting is important to make the IoT device network more sustainable from the environmental point of view. Different state-of-the-art energy harvesters based on mechanical, aeroelastic, wind, solar, radiofrequency, and pyroelectric mechanisms are discussed in this review article. To reduce the power consumption of the batteries, a vital role is played by power management integrated circuits (PMICs), which help to enhance the system's life span. Moreover, PMICs from different manufacturers that provide power management to IoT devices have been discussed in this paper. Furthermore, the energy harvesting networks can expose themselves to prominent security issues putting the secrecy of the system to risk. These possible attacks are also discussed in this review article