Perpetual Sensing: Experiences with Energy-Harvesting Sensor Systems

Industry forecasts project the number of connected devices will outpace the global population by orders of magnitude in the next decade or two. These projections are application driven: smart cities, implantable health monitors, responsive buildings, autonomous robots, driverless cars, and instrumented infrastructure are all expected to be drivers for the growth of networked devices. Achieving this immense scale---potentially trillions of smart and connected sensors and computers, popularly called the "Internet of Things"---raises a host of challenges including operating system design, networking protocols, and orchestration methodologies. However, another critical issue may be the most fundamental: If embedded computers outnumber people by a factor of a thousand, how are we going to keep all of these devices powered? In this dissertation, we show that energy-harvesting operation, by which devices scavenge energy from their surroundings to power themselves after they are deployed, is a viable answer to this question. In particular, we examine a range of energy-harvesting sensor node designs for a specific application: smart buildings. In this application setting, the devices must be small and sleek to be unobtrusively and widely deployed, yet shrinking the devices also reduces their energy budgets as energy storage often dominates their volume. Additionally, energy-harvesting introduces new challenges for these devices due to the intermittent access to power that stems from relying on unpredictable ambient energy sources. To address these challenges, we present several techniques for realizing effective sensors despite the size and energy constraints. First is Monjolo, an energy metering system that exploits rather than attempts to mask the variability in energy-harvesting by using the energy harvester itself as the sensor. Building on Monjolo, we show how simple time synchronization and an application specific sensor can enable accurate, building-scale submetering while remaining energy-harvesting. We also show how energy-harvesting can be the foundation for highly deployable power metering, as well as indoor monitoring and event detection. With these sensors as a guide, we present an architecture for energy-harvesting systems that provides layered abstractions and enables modular component reuse. We also couple these sensors with a generic and reusable gateway platform and an application-layer cloud service to form an easy-to-deploy building sensing toolkit, and demonstrate its effectiveness by performing and analyzing several modest-scale deployments.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138686/1/bradjc_1.pd

Avoin alustakehitys IEEE 802.15.4 -standardin mukaisessa langattomassa automaatiossa

This doctoral dissertation focuses on open source platform development in wireless automation under IEEE 802.15.4 standard. Research method is empirical. A platform based approach, which targets to the design of a generic open source sensor platform, was selected as a design method. The design targets were further focused by interviewing the experts from the academia and industry. Generic and modular sensor platform, the UWASA Node, was developed as an outcome of this process. Based on the implementation results, a wireless sensor and actuator network based on the UWASA Node was a feasible solution for many types of wireless automation applications. It was also possible to interface it with the other parts of the system. The targeted level of sensor platform genericity was achieved. However, it was also observed that the achieved level of genericity increased the software complexity. The development of commercial sensor platforms, which support IEEE 802.15.4 sensor networking, has narrowed down the role of open source sensor platforms, but they are not disappearing. Commercial software is usually closed and connected to a specified platform, which makes it unsuitable for research and development work. Even though there exits many commercial WSN solutions and the market expectations in this area are high, there is still a lot of work to do before the visions about Internet of Things (IoT) are fulfilled, especially in the context of distributed and locally centralized operations in the network. In terms of control engineering, one of the main research issues is to figure out how the well-known control techniques may be applied in wireless automation where WSN is part of the automation system. Open source platforms offer an important tool in this research and development work.Tämä väitöskirja käsittelee avointa alustakehitystä IEEE 802.15.4 -standardin mukaisessa langattomassa automaatiossa. Tutkimusmenetelmä on empiirinen. Työssä sovelletaan alustaperustaista suunnittelutapaa, joka tähtää yleiskäyttöisen avoimen anturialustan kehittämiseen. Suunnittelun tavoitteita tarkennettiin haastattelemalla alan asiantuntijoita teollisuudesta ja yliopistomaailmasta. Tuloksena suunniteltiin ja toteutettiin anturialusta, the UWASA Node. Implementointituloksista voidaan vetää johtopäätös, että anturialustan tavoiteltu yleiskäyttöisyystaso saavutettiin. Toisaalta saavutettu yleiskäyttöisyystaso lisäsi alustan ohjelmistoarkkitehtuurin monimutkaisuutta. Kaupallisten IEEE 802.15.4 -standardia tukevien anturialustojen tulo markkinoille vähentää avointen anturialustojen käyttöä, mutta ne eivät ole katoamassa. Kaupalliset ohjelmistot ovat tyypillisesti suljettuja ja sidoksissa tiettyyn alustaan, mikä tekee niistä sopimattomia tutkimus- ja tuotekehityskäyttöön. Vaikka nykyään on saatavilla useita kaupallisia langattomia anturi- ja toimilaiteverkkoja, vaaditaan vielä paljon työtä ennen kun kaikki esineiden Internetiin (Internet of Things) liittyvät visiot voidaan toteuttaa. Tämä koskee erityisesti langattomassa anturi- ja toimilaiteverkossa hajautetusti tai paikallisesti toteutettavia toimintoja. Säätötekniikan näkökulmasta keskeinen kysymys on, miten tunnettuja säätömenetelmiä tulee soveltaa langattomassa automaatiossa, jossa langaton anturi- ja toimilaiteverkko on osa automaatiojärjestelmää. Avoimet anturialustat ovat tärkeä työkalu sen selvittämisessä.fi=vertaisarvioitu|en=peerReviewed

Energy adaptive buildings:From sensor data to being aware of users

Energie besparen is fundamenteel voor het realiseren van een duurzame energievoorziening. Het besparen van energie draagt bij aan milieudoelstellingen, verbetert de zakelijke positie van landen, en levert werkgelegenheid. Er zijn tal van mogelijkheden voor het behalen van aanzienlijke energiebesparingen in gebouwen gezien individuen en bedrijven gebaat zijn bij energiebesparingen en daardoor zelf de verantwoordelijkheid nemen. Het is bewezen dat het gedrag van gebouwgebruikers een grote impact heeft op de verwarming en ventilatie van ruimtes, en op het energieverbruik van verlichting en huishoudelijke apparaten. Huidige gebouwautomatiseringssystemen kunnen niet overweg met veranderingen in het gedrag van gebruikers en zijn daardoor niet in staat om het energieverbruik terug te dringen met behoud van gebruikerscomfort. Mijn promotieonderzoek wordt gedreven door het doel om een dergelijk energy adaptive building te realiseren dat intelligent systemen aanstuurt en zich aanpast aan de gebruiker en gebruikersactiviteiten door deze te leren, terwijl energieverspilling wordt teruggedrongen. Mijn focus ligt op het ontwikkelen van een framework, beginnende bij de hardware infrastructuur voor sensoren en actuatoren, het verwerken en analyseren van de sensordata, en de nodige informatie over de omgeving en gebruikersactiviteiten verkrijgen zodat het gebouw aangestuurd kan worden. Onze oplossing kan 35% besparen op het totale energieverbruik van een gebouw. Als een succesverhaal, besparen de software systemen zelfs 80% op het energieverbruik van de verlichting in het restaurant van de Bernoulliborg. Wij commercialiseren de resultaten verkregen in ons onderzoek door het oprichten van de start-up SustainableBuildings, een spin-off bedrijf van onze universiteit, om onze oplossing aan te bieden aan kantoorgebouwen.Saving energy is the foundation for achieving a sustainable energy supply. Saving energy contributes to environmental objectives, improves the competitiveness of a country’s businesses, and boosts employment. There are numerous opportunities for achieving significant energy savings in buildings since individuals and businesses have an interest themselves in saving energy and will shoulder the responsibility for doing so.Occupant behaviour has shown to have large impact on space heating and cooling demand, energy consumption of lighting and appliances. Current building automation systems are unable to cope with changes caused by occupants’ behaviour and interaction with the environment, therefore they fail to reduce unnecessary energy consumption while preserving user comfort.My PhD research is driven by the aim of realising such energy adaptive buildings that facilitate intelligent control, that learn and adapt to the building users and their activities, while reducing energy waste. My particular focus is on a framework, going from the hardware infrastructure for sensing and actuating, to processing and analysing sensor data, providing necessary information about the environment and occupants’ activities for the system to produce adaptive control strategies, regulating the environment accordingly.Our solution can save 35% of energy for a single building. As a success story, the software system saves 80 percent on energy spent for lighting in the restaurant of the Bernoulliborg.We are commercialising the results of our research by creating the SustainableBuildings start-up, a spin-off from our university, to offer the solutions to non-residential buildings, first in the Netherlands, and later extending wider