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Preparing the Uppsala University wave energy converter generator for large-scale production
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
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2014 (English)Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Halifax, Canada, 2014.
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-237554OAI: oai:DiVA.org:uu-237554DiVA, id: diva2:768281
Conference
5th International Conference on Ocean Energy
Available from: 2014-12-03 Created: 2014-12-03 Last updated: 2024-12-10
In thesis
1. Automated Production Technologies and Measurement Systems for Ferrite Magnetized Linear Generators
Open this publication in new window or tab >>Automated Production Technologies and Measurement Systems for Ferrite Magnetized Linear Generators
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The interest in breaking the historical dependence on fossil energy and begin moving towards more renewable energy sources is rising worldwide. This is largely due to uncertainties in the future supply of fossil fuels and the rising concerns about humanity’s role in the currently ongoing climate changes. One renewable energy source is ocean waves and Uppsala University has since the early 2000s been performing active research in this area. The Uppsala wave energy concept is centered on developing linear generators coupled to point absorbing buoys, with the generator situated on the seabed and connected to the buoy on the sea surface via a steel wire. The motion of the buoy then transfers energy to the generator, where it is converted into electricity and sent to shore for delivery into the electrical grid.

This thesis will mainly focus on the development and evaluation of technologies used to automate the manufacturing of the translator, a central part of the linear generator, using industrial robotics. The translator is a 3 m high and 0.8 m wide three sided structure with an aluminum pipe at its center. The structure consists of alternating layers of steel plates (pole-shoes) and ferrite magnets, with a total of 72 layers per side. To perform experiments on translator assembly and production, a robot cell (centered on an IRB6650S industrial robot) complimented with relevant tools, equipment and security measures, has been designed and constructed. The mounting of the pole-shoes on the central pipe, using the industrial robot, proved to be the most challenging task to solve. However, by implementing a precise work-piece orientation calibration system, combined with selective compliance robot tools, the task could be performed with mounting speeds of up to 50 mm/s. Although progress has been made, much work still remains before fully automated translator assembly is a reality.

A secondary topic of this thesis is the development of stand-alone measurement systems to be used in the linear generator, once it has been deployed on the seabed. The main requirements of such a measurement system is robustness, resistance to electrical noise, and power efficiency. If possible the system should also be portable and easy to use. This was solved by developing a custom measurement circuit, based on industry standard 4–20 mA current signals, combined with a portable submersible logging unit. The latest iteration of the system is small enough to be deployed and retrieved by one person, and can collect data for 10 weeks before running out of batteries. Future work in this area should focus on increasing the usability of the system.

The third and final topic of this thesis is a short discussion of an engineering approach to kinetic energy storage, in the form of high-speed composite flywheels, and the design of two different prototypes of such flywheels. Both designs gave important insights to the research group, but a few crucial design faults unfortunately made it impossible to evaluate the full potential of the two designs.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. p. 79
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1573
Keywords
industrial robotics, automation, self-sensing, calibration, ferrite, linear generator, wave energy, offshore, measurements, electronics, kinetic energy storage, reluctance motor
National Category
Robotics and automation Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-330866 (URN)978-91-513-0095-5 (ISBN)
Public defence
2017-11-24, Polhemsalen, Lägerhyddsvägen 1, 752 37 Uppsala, 13:00 (English)
Opponent
Supervisors
Available from: 2017-11-02 Created: 2017-10-08 Last updated: 2025-02-05
2. Robotized Production Methods for Special Electric Machines
Open this publication in new window or tab >>Robotized Production Methods for Special Electric Machines
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A research project on renewable energy conversion from ocean waves to electricity was started at the Division of Electricity at Uppsala University (UU) in 2001. The Wave Energy Converter (WEC) unit developed in this project is intended to be used in large offshore WEC farms and has therefore been designed with large-scale production in mind. The concept has now also been commercialized by the spin-off company Seabased Industry AB.

An essential part of the UU WEC is the linear direct-drive generator. This thesis presents the pilot work on developing robotized production methods for this special electric machine. The generator design is here investigated and four different backbreaking, monotone, potentially hazardous and time consuming manual production tasks are selected for automation. A robot cell with special automation equipment is then developed and constructed for each task. Simplicity, reliability and flexibility are prioritized and older model pre-owned industrial robots are used throughout the work. The robot cells are evaluated both analytically and experimentally, with focus on full scale experiments. It is likely that the developed production methods can be applied also for other similar electric machines.

The main focus in the thesis is on robotized stator cable winding. The here presented robot cell is, to the knowledge of the author, the first fully automated stator cable winding setup. Fully automated winding with high and consistent quality and high flexibility is demonstrated. Significant potential cost savings compared to manual winding are also indicated. The robot cell is well prepared for production, but further work is required to improve its reliability.

The other three developed robot cells are used for stator stacking, surface mounting of permanent magnets on translators and machining of rubber discs. All robot cell concepts are experimentally validated and considerable potential cost savings compared to manual production are indicated. Further work is however required with regards to autonomy and reliability.

Finally, the thesis presents a pedagogical development work connected to the research on robotized production methods. A first cycle course on automation and robot engineering is here completely reworked, as it is structured around three real-world group project tasks. The new course is evaluated from the examination results, the students’ course evaluations and the feedback from the teachers during six years. The students greatly appreciated the new course. It is indicated that the developed teaching approach is effective in teaching both classical and modern engineering skills.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2018. p. 82
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1608
Keywords
Industrial robotics, Assembly automation, Large-scale production, Cable winding, Linear generator, Wave energy converter, Wave power, Engineering education
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-335504 (URN)978-91-513-0177-8 (ISBN)
Public defence
2018-02-02, Polhemsalen, Lägerhyddsvägen 1, Uppsala, 13:00 (English)
Opponent
Supervisors
Available from: 2018-01-12 Created: 2017-12-07 Last updated: 2018-03-07
3. Industrial robot as main equipment for testing and production of Wave Energy Converters
Open this publication in new window or tab >>Industrial robot as main equipment for testing and production of Wave Energy Converters
2025 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Since 2001, research and development on the conversion of ocean wave energy into electricity has been conducted at the Division of Electricity at Uppsala University. Different Wave Energy Converter (WEC) technologies has been developed, such as the point-absorber linear Uppsala University WEC (UU-WEC) and the Low-RPM Torque Converter WEC (LRTC-WEC). 

This thesis focuses primarily on the development of a robotized dry test rig, to facilitate assessment of different WEC technologies in house. An existing industrial six degrees of freedom robot system is used to emulate buoy movement on the sea surface, with regard to the impact of hydrodynamic forces in real time. Two different methods for integrating a hydrodynamic model to the robot controller are presented: the force control and the position control methods. Both methods are evaluated and validated across various regular and irregular wave climates, as well as for different theoretical buoy shapes.  

The secondary focus in this thesis is the development of robotized production methods for the UU-WEC. The surface mounting of Neodymium Iron Boron (Nd2Fe14B) magnets and the cutting of rubber discs are investigated, resulting in viable solutions that include development and validation of robot tooling and robot cell proposals. 

A smaller segment of the thesis examines the use of robotics in teaching a course for bachelor engineering students. At the outbreak of the COVID-19 pandemic a challenging task was imposed: a swift shift to online distant education. A major task was to replace physical lab exercises with video recordings, detailed instructions and simulated laboratory environments. The results indicated that the upgraded online education successfully meet the course objectives.

The final part of the thesis investigates the use of WECs for powering a desalination plant. Desalination presents a viable solution for islands or coastal regions deficient in freshwater resources, but is also an energy intensive process. Practical experiment evaluated the possibility of utilizing the UU-WEC as power source for desalination plants.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2025. p. 78
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 2485
Keywords
Dry test rig, Industrial robotics, Manufacturing automation, Large-scale production, Linear generator, Wave energy converter, Engineering education, Desalination
National Category
Robotics and automation Other Electrical Engineering, Electronic Engineering, Information Engineering Communication Systems Control Engineering
Research subject
Engineering Science with specialization in Science of Electricity; Engineering Science with specialization in Electronics; Engineering science with specialization in Applied Mechanics; Engineering Science with specialization in industrial engineering and management; Electrical Engineering with specialization in Automatic Control; Engineering Science with specialization in industrial engineering and management
Identifiers
urn:nbn:se:uu:diva-544285 (URN)978-91-513-2337-4 (ISBN)
Public defence
2025-02-10, Polhem, Lägerhyddsvägen 1, 75237 Uppsala, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2025-01-17 Created: 2024-12-10 Last updated: 2025-02-05

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Hultman, ErikEkergård, BoelKamf, TobiasSalar, DanaLeijon, Mats

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