Design and development of multifunctional energy harvesting and storage systems for sensor applications

This research focuses on the design and development of multifunctional components intended to provide three basic functions: (i) power generation, (ii) power storage, and (iii) structural support. They are made of composite multi-material systems that include smart materials. By combining various functions into the same component significant performance, weight, space, assembly and packing benefits can be achieved. A major portion of this thesis is devoted to the use of piezoelectric layers in order to generate few milliwatts of power and enhance the utility of electrical mobility products and subsystems while facilitating new venues for implementing such devices. Shoes and pneumatic tires were used to harvest energy from their innate motion and various useful applications of harvested energy have been demonstrated in the form of sensors and power sources for larger devices. Shoe-based power generation can be used for charging Radio Frequency IDentification (RFID) tags, GPS sensors, portable electronics, etc. Tire-based power generation can be used for powering battery-less wireless Tire Pressure Monitoring Systems (TPMS), wireless Vehicle Speed Sensors (VSS), tire health monitoring sensors, etc. Fully functional proof-of-product prototypes of a variety of multifunctional components were developed and subjected to experimentation and testing using custom designed and built lab-scale made experimental machinery. Contrary to the paradigm, the possibility of using piezoelectric materials in automotive tires to produce few watts of power (>2 watts) has been successfully demonstrated with applications ranging from powering more demanding sensors to onboard batteries. An Electronic Vehicle Control System (EVCS) with electronic differential and cruise control capabilities has also been designed, developed and tested on the Extended Range Plug-In Hybrid vehicle previously developed at UOIT

Design and development of multifunctional energy harvesting and storage systems for sensor applications

This research focuses on the design and development of multifunctional components intended to provide three basic functions: (i) power generation, (ii) power storage, and (iii) structural support. They are made of composite multi-material systems that include smart materials. By combining various functions into the same component significant performance, weight, space, assembly and packing benefits can be achieved. A major portion of this thesis is devoted to the use of piezoelectric layers in order to generate few milliwatts of power and enhance the utility of electrical mobility products and subsystems while facilitating new venues for implementing such devices. Shoes and pneumatic tires were used to harvest energy from their innate motion and various useful applications of harvested energy have been demonstrated in the form of sensors and power sources for larger devices. Shoe-based power generation can be used for charging Radio Frequency IDentification (RFID) tags, GPS sensors, portable electronics, etc. Tire-based power generation can be used for powering battery-less wireless Tire Pressure Monitoring Systems (TPMS), wireless Vehicle Speed Sensors (VSS), tire health monitoring sensors, etc. Fully functional proof-of-product prototypes of a variety of multifunctional components were developed and subjected to experimentation and testing using custom designed and built lab-scale made experimental machinery. Contrary to the paradigm, the possibility of using piezoelectric materials in automotive tires to produce few watts of power (>2 watts) has been successfully demonstrated with applications ranging from powering more demanding sensors to onboard batteries. An Electronic Vehicle Control System (EVCS) with electronic differential and cruise control capabilities has also been designed, developed and tested on the Extended Range Plug-In Hybrid vehicle previously developed at UOIT

Piezoelectric energy harvesting utilizing metallized poly-vinylidene fluoride (PVDF)

The primary objective of the enclosed thesis was to identify and develop a viable concept for an autonomous sensor system that could be implemented onto the surface of a road. This was achieved by an analysis of combinations of materials, sensing methods, power sources, microsystems, energy storage options, and wireless data transmission systems; the sub-systems required for an autonomous sensor. Comparison of sensing methods for the application of an on-road, autonomous sensor yielded a piezoelectric material as the ideal choice. A 52μm thin film of poly- vinylidene fluoride (PVDF) was chosen and coated with Ag electrodes on both sides.This was due to many constraints imposed by the intended environment including: physical, electrical, thermal, and manufacturing characteristics. One major hurdle in providing an autonomous sensor is the power source for the sensing, encoding, and transmission of data. Research involved determining the option best suited for providing a power source for the combination of sensors and wireless telemetry components. An energy budget of 105μJ was established to determine an estimate of energy needed to wirelessly transmit data with the selected RF transmitter. Based on these results, several candidates for power sources were investigated, and a piezoelectric energy harvesting system was identified to be the most suitable. This is an ideal case as the sensor system was already based on a piezoelectric material as the sensing component. Thus, a harvesting circuit and the sensor can be combined into one unit, using the same material. By combining the two functions into a single component, the complexity, cost and size of the unit are effectively minimized. In order to validate the conclusions drawn during this sensor system analysis and conceptual research, actual miniaturized systems were designed to demonstrate the ability to sense and harvest energy for the applications in mind. This secondary aspect of the research was a proof-of-concept, developing two prototype energy harvesting/sensing systems. The system designed consisted of a PVDF thin film with a footprint of 0.2032 m x 0.1397m x 52μm. This film was connected to an energy-harvesting prototype circuit consisting of a full-wave diode bridge and a storage capacitor. Two prototypes were built and tested, one with a 2.2μF capacitor, the other with a 0.1mF capacitor. The film was first connected to an oscilloscope and impulsed in an open circuit condition to determine the sensor response to a given signal. Secondly, the energy harvesting circuits were tested in conjunction with the film to test the energy supply component of the system. Lastly, the film and both energy-harvesting systems underwent full scale testing on a road using a vehicle as the stimulus. Both systems showed excellent rectification of the double polarity input with an evident rise in voltage across the capacitor, meaning energy was harvested. Typical results from the tests yielded 600-800mV across the 2.2μF capacitor, harvesting only a few μJ of energy. The 0.1mF capacitor system yielded approximately 4V per vehicle axle across the capacitor, harvesting 400-800μJ of energy. This equates to 4-8 times the required energy for wireless data transmission of the measurement data, which was estimated by other research groups to be on the order of 105μJ for the given system, and therefore proves the concept both, for bench-top and full-scale on-road experiments under controlled laboratory conditions

A Multi-Hop 6LoWPAN Wireless Sensor Network for Waste Management Optimization

In the first part of this Thesis several Wireless Sensor Network technologies, including the ones based on the IEEE 802.15.4 Protocol Standard like ZigBee, 6LoWPAN and Ultra Wide Band, as well as other technologies based on other protocol standards like Z-Wave, Bluetooth and Dash7, are analyzed with respect to relevance and suitability with the Waste Management Outsmart European FP7 Project. A particular attention is given to the parameters which characterize a Large Scale WSN for Smart Cities, due to the amount of sensors involved and to the practical application requested by the project. Secondly, a prototype of sensor network is proposed: an Operative System named Contiki is chosen for its portability on different hardware platforms, its Open Source license, for the use of the 6LoW-PAN protocol and for the implementation of the new RPL routing protocol. The Operative System is described in detail, with a special focus on the uIPv6 TCP/IP stack and RPL implementation. With regard to this innovative routing proto col designed specifically for Low Power Lossy Networks, chapter 4 describes in detail how the network topology is organized as a Directed Acyclic Graph, what is an RPL Instance and how downward and upward routes are constructed and maintained. With the use of several AVR Atmel modules mounting the Contiki OS a real WSN is created and, with an Ultrasonic Sensor, the filling level of a waste basket prototype is periodically detected and transmitted through a multi-hop wireless network to a sink nodeope

A Low-Power BFSK/OOK Transmitter for Wireless Sensors

In recent years, significant improvements in semiconductor technology have allowed consistent development of wireless chipsets in terms of functionality and form factor. This has opened up a broad range of applications for implantable wireless sensors and telemetry devices in multiple categories, such as military, industrial, and medical uses. The nature of these applications often requires the wireless sensors to be low-weight and energy-efficient to achieve long battery life. Among the various functions of these sensors, the communication block, used to transmit the gathered data, is typically the most power-hungry block. In typical wireless sensor networks, transmission range is below 10 meters and required radiated power is below 1 milliwatt. In such cases, power consumption of the frequency-synthesis circuits prior to the power amplifier of the transmitter becomes significant. Reducing this power consumption is currently the focus of various research endeavors. A popular method of achieving this goal is using a direct-modulation transmitter where the generated carrier is directly modulated with baseband data using simple modulation schemes. Among the different variations of direct-modulation transmitters, transmitters using unlocked digitally-controlled oscillators and transmitters with injection or resonator-locked oscillators are widely investigated because of their simple structure. These transmitters can achieve low-power and stable operation either with the help of recalibration or by sacrificing tuning capability. In contrast, phase-locked-loop-based (PLL) transmitters are less researched. The PLL uses a feedback loop to lock the carrier to a reference frequency with a programmable ratio and thus achieves good frequency stability and convenient tunability. This work focuses on PLL-based transmitters. The initial goal of this work is to reduce the power consumption of the oscillator and frequency divider, the two most power-consuming blocks in a PLL. Novel topologies for these two blocks are proposed which achieve ultra-low-power operation. Along with measured performance, mathematical analysis to derive rule-of-thumb design approaches are presented. Finally, the full transmitter is implemented using these blocks in a 130 nanometer CMOS process and is successfully tested for low-power operation

Contributions to the development of active RFID systems at the 433 MHz band

Donat el potencial de la tecnologia RFID activa, aquesta tesi contribueix al seu desenvolupament centrant-se en les capes més baixes de la pila de protocols, és a dir, la capa física i la capa d'enllaç de dades. Aquestes capes determinen l'abast de la comunicació entre l'interrogador i les etiquetes, el nombre d'etiquetes que un interrogador pot llegir per segon i el consum d'energia que utilitzen les etiquetes en el procés, que en són els paràmetres de rendiment clau. A la capa física la tesi avalua els aspectes de propagació de la banda 433 MHz en diferents entorns i els compara amb la banda 2.4 GHz. Els resultats demostren que, per a la mateixa potència de transmissió, els sistemes RFID actius que funcionen a la banda 433 MHz aconsegueixen un millor abast de comunicació gràcies a unes millors característiques de propagació. A la capa d'enllaç de dades la tesi proposa LPDQ (Low-Power Distributed Queuing), un nou protocol d'accés al medi, i el compara amb FSA (Frame Slotted ALOHA). LPDQ combina LPL (Low-Power Listening) per a la sincronització de xarxa i DQ (Distributed Queuing) per a la transmissió de dades. En comparació amb el cas òptim de FSA, LPDQ aconsegueix un rendiment proper al màxim teòric (99.5%) independentment del nombre d'etiquetes i redueix el consum d'energia de les etiquetes en més d'un 10%.Dado el potencial de la tecnología RFID activa, esta tesis contribuye a su desarrollo centrándose en las capas más bajas de la pila de protocolos, es decir, la capa física y la capa de enlace de datos. Estas capas determinan el alcance de la comunicación entre el interrogador y las etiquetas, el número de etiquetas que un interrogador puede leer por segundo y el consumo de energía que utilizan las etiquetas en el proceso, que son los parámetros de rendimiento clave. En la capa física la tesis evalúa los aspectos de propagación de la banda 433 MHz en diferentes entornos y los compara con la banda 2.4 GHz. Los resultados demuestran que, para la misma potencia de transmisión, los sistemas RFID activos que funcionan en la banda 433 MHz consiguen un mejor alcance de comunicación gracias a unas mejores características de propagación. En la capa de enlace de datos la tesis propone LPDQ (Low-Power Distributed Queuing), un nuevo protocolo de acceso al medio, y lo compara con FSA (Frame Slotted ALOHA). LPDQ combina LPL (Low-Power Listening) para la sincronización de red y DQ (Distributed Queuing) para la transmisión de datos. En comparación con el caso óptimo de FSA, LPDQ consigue un rendimiento cercano al máximo teórico (99.5%) independientemente del número de etiquetas y reduce el consumo de energía de las etiquetas en más de un 10%.Given the potential of active RFID technology, this thesis contributes to its development by focusing on the lowest layers of the stack, that is, the physical and data-link layers. These layers determine the tag communication range, packet throughput and energy consumption, which are key performance parameters. At the physical layer, the thesis studies propagation aspects of the 433 MHz band in different environments and compares it to the 2.4 GHz band, which is also used in active RFID systems. The results demonstrate that active RFID systems operating at the 433 MHz band can achieve a better communication range at the same transmit power due to better propagation characteristics. At the data-link layer, the thesis proposes LPDQ (Low-Power Distributed Queuing), a new MAC (media access control) protocol, and compares it to FSA (Frame Slotted ALOHA). LPDQ combines LPL (Low-Power Listening) for network synchronization and DQ (Distributed Queuing) for data transmission. Compared to the optimal FSA case, LPDQ can achieve a performance close to the theoretical maximum (99.5%), regardless of the number of tags, and reduces tag energy consumption by more than 10%

Road Condition Estimation with Data Mining Methods using Vehicle Based Sensors

The work provides novel methods to process inertial sensor and acoustic sensor data for road condition estimation and monitoring with application in vehicles, which serve as sensor platforms. Furthermore, methods are introduced to combine the results from various vehicles for a more reliable estimation

ctOS-TPMS

Hoy en día los elementos de seguridad de los vehículos se han convertido en una pieza clave a la hora de evitar accidentes y de reducir las posibles lesiones que estos puedan producir. De entre todos los sistemas de seguridad existentes, este proyecto se enfoca en el TPMS, el sistema de monitorización de presión de los neumáticos obligatorio desde 2014 en todos los vehículos nuevos de la categoría M1, que proporciona información sobre el estado de los neumáticos y se comunica con el sistema central del vehículo mediante señales de radio, emitiendo este una serie de alertas en función de los datos de temperatura y presión que reciba. Ahora bien, estas señales se emiten sin cifrar, por lo que con las herramientas apropiadas es posible captar dicha señal y replicarla con datos falsos con el fin de confundir al vehículo. Para generar esta señal falsa hay que seguir varios pasos, empezando por la construcción de la trama de datos que se quiere enviar, continuando por la codificación de dicha trama (en este caso Manchester o Manchester diferencial) con el fin de provocar transiciones que permitan la sincronía de reloj o sincronía de bit, además de minimizar los posibles errores de transmisión, y por último la generación de la señal mediante la modulación de los datos digitales, lo que permite el envío de información a través de un medio analógico. Sin embargo, antes de generar la señal hay que demodular la señal recibida para obtener algunos datos importantes. Teniendo esto en cuenta, a lo largo del proyecto se explica el proceso para conseguir replicar dicha señal con éxito.

Circuits de transmission sans fil à faible puissance pour dispositifs implantables

Les systèmes de télémétrie existants -- Architectures et circuits des systèmes d'émission -- Système de transmission pour applications biomédicales -- Système de transmission proposé