Topic
eWind Solutions                          
  e-Wind  

M 28058 by Dave Santos  on Aug. 24, 2019,

e-Wind raising more funds while crashing a lot

From Geekwire: "In pursuit of the perfect kite, the eWind team has crashed and destroyed about three dozen drones. “It can get really depressing,” Schaefer said. It takes a week-and-a-half or even two to make a new one. “Our success comes from not dwelling on the failures, and moving on.”"

Standard power kites can crash dozens of times and pop right back up. Bespoke kiteplanes generally crash once, and its over. Crashworthiness is a critical AWES cost, reliability, and safety factor.

New Forum Moderation censored kPower's "unwelcoming" post that eWind's kiteplane designs have not provided enough vertical surface forward for reliable flight at the edge of the window (see below). eWind for years has declined to informally fly-off against KiteLab Ilwaco's prototypes based on cheap TRL9 COTS power kites rigged for passive dynamic-stability, to see what happens. eWind never even made it to the Pacific Coast an hour away; invited to inspect and observe in flight AWES developed at the World Kite Museum (citing briefly frozen roads). The kPower business argument is that if a better solution exists in eWind's backyard, on the Lower Columbia River, where kitesurfing was invented, then they should pivot to that, especially to meet public funding goals. eWind diligence so far is more toward securing lucrative start-up funding-rounds, rather than in broader domain research and expertise. They are betting their investors will continue to hang on meekly as they bet on only-invented-in-house R&D. kPower continues to refine the COTS-based alternatives that KiteLab Illwaco pioneered, and the offer to cross-license with eWind remains open. Good Luck to them in any case.


Specifically, the eWind design needs vertical keel area forward to not fall-off at the edge of the kite window or stall at low wind-speed sweeping crosswind. This falling-off is noticeable in the video. which seems to cut off before a stall. Other teams have made this same disastrous kite design error, like Enerkite, for example.


M 24276    Dec. 7, 2018     Joe Faust
TED Tethered Energy Drone :: energy kite system
Dec. 7, 2018     Joe Faust
TED Tethered Energy Drone :: energy kite system
eWind coining "TED"  for tethered energy drone for its energy kite system.
Pumping system is TED.

M 22419   March 1, 2017     Joe Faust

Re: eWind USDA Grant documentation


April 18, 2016
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Video is part of the article.

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eWind Solutions home:  http://www.ewindsolutions.com/
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Job opportunity: 
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Their news: 
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M 21991  Feb 18, 2017   Dave Santos
eWind USDA Grant documentation

 
Two docs copied from USDA server-

ACCESSION NO: 1006331 SUBFILE: CRIS
PROJ NO: OREW-2015-00340 AGENCY: NIFA OREK
PROJ TYPE: SMALL BUSINESS GRANT PROJ STATUS: TERMINATED
CONTRACT/GRANT/AGREEMENT NO: 2015-33610-23555 PROPOSAL NO: 2015-00340
START: 15 JUN 2015 TERM: 14 FEB 2016
GRANT AMT: $100,000 GRANT YR: 2015
AWARD TOTAL: $100,000
INITIAL AWARD YEAR: 2015
INVESTIGATOR: Schaefer, D. B.
PERFORMING INSTITUTION:
EWINDSOLUTIONS LLC
30678 SW ORCHARD DR
WILSONVILLE, OREGON 97070
NEXT GENERATION WIND ENERGY SYSTEMS FOR CASH-STRAPPED FARMERS AND COMMUNITIES

NON-TECHNICAL SUMMARY: eWind is proposing a highly efficient and low-cost wind-energy system for small and mid-sized farms that will produce approximately four times the electricity per year as comparably priced "conventional" wind turbines. This project addresses the USDA priorities of Energy Efficiency and Alternative and Renewable Energy and Agriculturally-related Manufacturing Technology. We directly support Energy Efficiency and Alternative and Renewable Energy since we will enable farms and rural communities to produce electricity from a clean wind source. Our project will also positively impact the fledgling unmanned aerial vehicle (UAV) industry, a manufacturing field that is increasingly used by farmers and agriculture. We also expect that most of the components of the airborne wind-energy system will be made and assembled in the U.S.--a combination that supports Agriculturally-related Manufacturing Technology. Finally, the project addresses the NIFA Societal Challenge Area 2: Climate Change. Adoption of our technology will reduce the overall carbon footprint of farms in fossil fuel-intensive electricity markets by producing clean wind energy.As Oregon farmer and Organically Grown Company (OGC) executive director Andy Westlund confesses, being one of the 800,000 small commercial farmers in America is challenging. Small farms are highly exposed to market risks, tend to focus on commodities, and have profit margins of just 3-4% (Hoppe, MacDonald, & Korb, 2010, p. 6). As such, small price changes of a single crop can have a substantial impact on their financial status(Page, 2011, p. 11). Thus, variable input costs, such as energy, can play havoc with financing annual operating loans(Page, 2011, p. 11). Therefore, reasonable methods of reducing the uncertainty of operating costs and diversifying the income of small farms are desirable--not just to the farmers themselves, but also for maintaining this sector of our agricultural industry.As Andy Westlund and many other small farmers have discovered, the desire to reduce operating costs is the primary factor that motivates farmers to produce their own electricity, usually through solar or wind (Page, 2011). Andy uses recycled solar panels and "primitive" wind turbines to reduce his energy bills. For small farmers, the use of alternative energy simultaneously lowers the operating cost of the farm by reducing the usage of grid electricity and reduces exposure to risk from fluctuating energy prices (Sands & Westcott, 2011; United States Department of Agriculture, 2011). Finally, farmers recognize that generating renewable energy and using fewer fossil fuels reduces dependence on foreign oil, providing greater local and national energy security while reducing the risk of climate change (Sustainable Agriculture Research & Education, 2008, p. 1).However, there are distinct challenges that have kept many small farms from implementing solar and wind renewable energy. The top three barriers that Oregon farmers identified are: 1) up-front project costs, 2) permitting, and 3) troublesome paperwork for the incentive programs(Page, 2011, p. 31). Andy Westlund, for example, had to secure county permits for his twenty-foot wind tower, which is sited just a few steps from his thirty-foot-tall house. Additionally, he admits that the electricity produced doesn't cover the up-front cost of the system.In addition to the general renewable energy challenges Andy has encountered, traditional wind turbines have difficulties specific to farmers that has limited their adoption. The construction of the wind tower can disrupt farming activities and cause soil compaction issues (Linowes, 2013). The tower and its blades can also pose an operating and safety problem for agriculture aerial work and can significantly hamper their access to cropland, in turn detrimentally affecting agricultural production(National Agricultural Aviation Association, 2014). Finally, while the permit and incentive program paperwork problems are important, the up-front costs of a large wind turbine can remove any chance of adoption by small farmers. For example, wind farms often used the Vestas V82-1.65 turbine (a 1.6 MW unit) which had an installed cost of approximately $3.3 million ($2,000 per kW capacity) (National Renewable Energy Laboratory, 2014). This is well outside the financial range of any small farm. While wind turbines are available in smaller sizes and prices, their efficiency drops quickly with the shorter tower while maintaining a similar level of product complexity. As a result, the system install cost doubles to $4,000 per kW capacity. Additionally, they actually produce only 10-15% of their stated generating capacity, about half the efficiency of utility scale systems (National Renewable Energy Laboratory, 2014). Thus, a wind tower system that may be affordable to the average small farmer--e.g., tens of thousands of dollars--does not produce enough electricity to make it financially sensible.eWind Solutions sees these obstacles as both a problem and an opportunity. Our intention is to remove these barriers and create affordable wind-energy generation systems tailored to small farms and rural communities. These systems will produce four times the power per year as comparably priced traditional wind turbines and are compliant with current federal regulations. We propose to do this by using a novel method for generating electricity from wind. Instead of a large, vertical wind tower with equally large blades, eWind Solutions uses airborne wind-energy technology. The system consists of a novel flying craft that is tethered to a power-generating ground station. Figure 1 shows the basic layout of the system. As the wind blows the flying craft downwind (step 1), the tether spins an electrical generator on the ground. When the tether is fully extended (step 2), the airborne craft glides back to the start of its power cycle (step 3), while the ground station simultaneously winds up the tether and the process is repeated (step 4).

OBJECTIVES: Technical ObjectivesThe primary technical objective to enable implementation of the eWind airborne wind energy system is the design and construction of the flying wing craft. As such, we have broken its research and development into a set of requirements and four Tasks. Task #1: Determine Design Variables Task #2: Design Flying Craft Task #3: Build Flying Craft Prototype Task #4: Test Prototype, Validate Models and Satisfy RequirementsThe requirements, listed in Table 4, come from a mixture of addressing the small farmers' needs, complying with FAA regulations, and our initial research. 1: Determine Design VariablesWhile the requirements form the general backbone of the research effort, they inform numerous aerodynamic design variables with various trade-offs. Thus, the first task of the proposal's technical objective is to determine the aerodynamic design variables that satisfy the requirements. First, the required tether tensions and wind speeds represent two points on the eWind power curve shown in Figure 3 and were chosen such that the nameplate capacity, when combined with the calculated capacity factor, will produce approximately the amount of electricity used each year by a small farm (see Table 3). To achieve these forces, the flying craft must have the appropriate balance of aerodynamic parameters. Most importantly, but not exclusively, in this case is the lift-to-drag ratio, number and arrangement of wings, control surfaces, and wing aspect ratio of the craft and a lightweight design.Second, we have determined that we must utilize at least 75% of the available tether length within the power generation stage of the flight pattern. Since the ground and FAA sets hard limits on our vertical operating range, we must use the tether length that can fit in that space efficiently. This directly affects the maneuverability of the craft. If the craft takes too long to turn, the top and bottom of the figure-8 flight patterns will start to impede into the vertical limits. Figure 5 demonstrates how a larger turn radius of the flying craft would reduce the length of the power-generating portion of our cycle. If the craft turns in a small radius, such as Example #1, it can fit more turns and pull out more tether in the available space. If, however, it has a larger turning radius such as Example #2, it quickly hits both the lower and upper vertical altitude limits before it has time to pull out as much tether. In this case, the flying craft would spend too much time resetting its position and not enough time generating power to meet our necessary capacity factor.While the 75% tether utilization requirement is necessary for the finished eWind system to achieve, we will, however, not be able to measure that value using the Phase I flying craft prototype. Thus, we have determined that a turn radius of 20 m or less will demonstrate that the flying craft will be able meet that requirement when it can be directly measured during a Phase II prototype of the full power-generating system. The advantage of this modified requirement is that we can measure it directly during Phase I testing. Working with Dr. Roberto Albertani of Oregon State University, the result of Task #1 will be a computer model that allows us to determine the combination of aerodynamic variables (e.g. number of wings, wing area, wing length, chord, etc.) that will best meet our requirements.Once we have determined the aerodynamic properties of the flying craft, we will move on to the task of physically designing it. This will include the incorporation of the aerodynamic properties with material selection, structural design, and mechanical control mechanisms. Using a 3-D structural model, we will evaluate the dynamic forces on the craft, as well as a finite element stress analysis. In combination, these will allows us to work out any significant design problems before we progress to the construction of the craft prototype.Once the flying craft is fully designed, our research will transition to the construction of a full-sized prototype. Initial estimations indicate that the prototype will be approximately eight feet across. Using existing tools developed by eWind, we have the space and expertise to create custom wing molds of this size. These, in turn, will create the actual wings while retaining the ability to be easily modified. Since it is reasonable to assume that the design will be tweaked upon actually constructing a prototype, the mold's potential to be easily adjusted is crucial. Once the prototype is fully constructed, we must ensure that it actually conforms to our expectations and requirements. Thus, we will design and implement a series of experiments to test the values detailed by the requirements (i.e. the tether forces and the turning radius detailed in Table 4). Outdoor tests at various wind speeds will measure the force the craft exerts on a tether using a strain gauge. The turning radius of the flying craft will be measured by the placement of GPS sensors in the body and wing tips. These will capture the spatial position of each point on the craft and will allow evaluation of the maneuverability. The final objective of the research effort is to prove the feasibility of designing, developing, and flying the envisioned craft that will enable highly efficient and low-cost power generation within the defined settings. We will produce a final report summarizing our work: the design choices of the craft, the construction and testing of the prototype, and the success of meeting our tension and turning radius requirements.
APPROACH: Usage of general engineering tools and principles, such as design-of-experiments, failure modes and effects analysis, statistical principles, finite element analysis, and computational fluid dynamics.
PROGRESS: 2015/06 TO 2016/02
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported
IMPACT: 2015/06 TO 2016/02
What was accomplished under these goals? Impact: The goal of eWind Solutions and this research is to create an airborne wind energy system that will provide cost effective renewable energy to small and mid-sized farms. Not only will the cost of the electricity produced be comparable to the price of the local utility grid (depending on wind quality, local utility prices, etc.), but the system will have several advantages over existing solutions (traditional wind towers, solar, other airborne wind energy companies). eWind is scaling the system to produce approximately the amount of electricity used each year by a small farm. When combined with a local utility net-metering arrangement, this can alleviate most of the farm's annual electric bill. The system is four times more efficient than existing traditional wind turbines of comparable cost. In addition, our system requires no heavy construction equipment or large concrete pad, negating the soil compaction issues that have soured some farmers to wind energy. Land space use is minimal land space, allowing more room for cultivation, a clear advantage over wind towers and solar panels. Finally, we are following existing FAA regulations. Therefore, we do not need special permission or waivers that other airborne wind energy companies are seeking in order to fly in the United States. When completed, the eWind airborne wind energy system will provide most of the electricity for a small farm for a fraction of the cost of a modern tractor (about $50,000). This will replace carbon intensive power generation and increase the financial resilience of our farming sector. This will also bring jobs to rural communities through installation and maintenance work. The goal of this grant was the development of the flying kite that will power the electrical generator. The entire system is complex, but the flying kite is one of the most technically challenging aspects of the development. It must be rugged, fast and highly maneuverable while producing enough tension on the attaching tether to turn the electrical generator. This grant focused on beginning that development by meeting the initial physical requirements of the kite, namely turning radius and pull strength. Results: eWind accomplished each goal laid out in the proposal objectives and goals. The primary means of measurement on our progress was the three physically measurable properties of the latest version of the kite. Specifically we wished to have a turning radius of less than 20m, a pull strength of 2.1kN at 7 m/s of wind and a pull strength of 3.8kN at 9 m/s of wind. These measured objectives required the completion of numerous other tasks that were harder to quantify, but no less important to the success of the project. Specifically, in collaboration with Oregon State University, we developed a computer model that predicts the performance of a given kite design (with numerous other variables: flight path, tether properties, generator efficiency, etc.). We combined this with other Computer Aided Drafting (CAD) and aerodynamic modeling software to create a pipeline from initial idea to design to build to test. In addition, we streamlined the manufacturing of prototypes using the CAD software and 3D printers, allowing us to go from improvement idea to built prototype in just a few days. While there were minor changes to our work plan which could be expected of any technology development effort, we followed the proposed steps closely. They showed we had a realistic and appropriateplan before beginning this project. While the building ofthis software and construction pipeline took a large portion of the grant period, we were still able to meet our quantifiable goals. There were three criteria we measured (as mentioned above): 1) Turning radius of less than 20m: This was accomplished during one of our earlier prototypes and has been the expectation and standard for all following kites. It was successfully achieved and measured during our latest test, where we had a consistent turning radius of approximately 10 m. 2 and 3) A pull strength of 2.1kN at 7 m/s of wind and a pull strength of 3.8kN at 9 m/s of wind: These two goals were not technically measured, but we are considering them accomplished. The final tests were performed in approximately 6.2 m/s winds. Since we are currently unable to force nature to provide the exact winds we desire on command, our best option is to use basic aerodynamic scaling equations to determine what our forces would be at faster wind speeds. In this case we measured 1.65 kN at 6.2 m/s wind. Because the force scales at the square of the wind speed, this equates to an expected force of 2.11 kN at 7 m/s and 3.40 kN at 9 m/s. While these estimations are based on rough, simple calculations, they have proven to be accurate to approximately 10%. Therefore, even though the higher wind speed estimate is slightly below the grant goal, it is close enough that it is likely we will meet it with the current prototype or, failing that, with the next iteration that will continue our tension improvements. We anticipate being able to directly measure the force at these faster wind speeds the next time the weather provides them to us. It should also be noted that all these measurements are collected by a custom built electronics system. Elements of this system on the kite are: location, speed and orientation. Ground elements record the tension on the tether and wind speed. A nearby laptop computer collects both the ground and kite signals and stores everything at a 5 Hz rate on a nearby laptop. The electronics also have the capability to send signals from the laptop back up to the kite. While the kite is currently human controlled, this capability is the first step in transferring control to the computer and beginning the work of creating an autonomous flying system. Finally, because most of our demonstrative progress is best shown in pictures and plots, we have created a final report outside of this web form. This report will combine pictures of our prototypes and data collected from their testing. In addition, we will include the software results created for us by Oregon State University that describes their efforts and conclusions.
PUBLICATIONS (not previously reported): 2015/06 TO 2016/02
No publications reported this period.

Item No. 1 of 1
ACCESSION NO: 1010100 SUBFILE: CRIS
PROJ NO: OREW-2016-03858 AGENCY: NIFA OREK
PROJ TYPE: SMALL BUSINESS GRANT PROJ STATUS: NEW
CONTRACT/GRANT/AGREEMENT NO: 2016-33610-25696 PROPOSAL NO: 2016-03858
START: 01 SEP 2016 TERM: 31 AUG 2018
GRANT AMT: $600,000 GRANT YR: 2016
AWARD TOTAL: $600,000
INITIAL AWARD YEAR: 2016
INVESTIGATOR: Schaefer, D. B.
PERFORMING INSTITUTION:
EWINDSOLUTIONS LLC
30678 SW ORCHARD DR
WILSONVILLE, OREGON 97070
CONTINUED DEVELOPMENT OF A NOVEL NEXT GENERATION AIRBORNE WIND ENERGY SYSTEM FOR SMALL AND MID SIZE FARMS
NON-TECHNICAL SUMMARY: As Oregon farmer and Organically Grown Company (OGC) executive director Andy Westlund confesses, being one of the 800,000 small commercial farmers in America is challenging (Hoppe, MacDonald, & Korb 2010). Small farms are highly exposed to market risks, tend to focus on commodities, and have profit margins of just 3-4% (Hoppe, MacDonald, & Korb 2010). As such, small price changes of a single crop can have a substantial impact on a farm's financial status (Page 2011). Variable input costs, such as energy, can play havoc with financing annual operating loans (Page 2011). Therefore, reasonable methods of reducing the uncertainty of operating costs and diversifying the income of small farms are desirable--not just for the farmers themselves, but also for maintaining this sector of our agricultural industry.In our market research, we conducted sit down interviews with more than 45 small farmers such as Andy Westlund. Not surprisingly, their desire to reduce operating costs is the primary factor that motivates farmers to produce their own electricity, usually through solar or wind. Andy uses recycled solar panels and primitive wind turbines to reduce his energy bills. For small farmers, the use of alternative energy simultaneously lowers the operating cost of the farm by reducing the usage of grid electricity and reduces exposure to risk from fluctuating energy prices (Sands & Westcott 2011; USDA 2011). Finally, farmers recognize that generating renewable energy and using fewer fossil fuels reduces dependence on foreign oil, providing greater local and national energy security while reducing the risk of climate change (Sustainable Agriculture Research & Education 2008).However, there are distinct challenges that have kept many small farms from implementing solar and wind energy. The top three barriers that Oregon farmers identified are (based on our own and external research): 1) up-front project costs, 2) permitting, and 3) troublesome paperwork for the incentive programs (Page 2011). Andy Westlund, for example, had to secure county permits for his twenty-foot wind tower, which is sited just a few steps from his thirty-foot-tall house. Additionally, he admits that the electricity produced will never cover the up-front cost of the system.In addition to the general renewable energy challenges Andy has encountered, traditional wind turbines have difficulties specific to farmers that have limited their adoption. The construction of the wind tower can disrupt farming activities and cause soil compaction issues (Linowes 2013). The tower and its blades can also pose an operating and safety problem for agriculture aerial work and can significantly hamper access to cropland, in turn detrimentally affecting agricultural production (National Agricultural Aviation Association 2014). Finally, while the permit and incentive program paperwork problems are important, the up-front costs of a large wind turbine can remove any chance of adoption by small farmers. For example, wind farms often use the Vestas V82-1.65 turbine (a 1.6 MW unit), which has an installed cost of approximately $3.3 million ($2,000 per kW capacity) (NREL 2014). This is well outside the financial range of any small farm. Although wind turbines are available in smaller sizes and prices, their efficiency drops quickly with the shorter tower while maintaining a similar level of product complexity. As a result, the system install cost doubles to $4,000 per kW capacity. Additionally, they actually produce only 10-15% of their stated generating capacity, about half the efficiency of utility scale systems (NREL 2014). Thus, a wind tower system that may be affordable to the average small farmer (e.g., tens of thousands of dollars) does not produce enough electricity to make it financially sensible.eWind Solutions sees these obstacles as both a problem and an opportunity. Our intention is to remove these barriers and create affordable wind energy generation systems tailored to small farms and rural communities. These systems will produce four times the power annually as comparably priced traditional wind turbines and are compliant with current federal regulations. We propose to do this by using a novel method for generating electricity from wind. Instead of a large, vertical wind tower with equally large blades, eWind Solutions uses airborne wind energy technology.The eWind system consists of three main components: a novel flying craft (1) that is tethered by a rope (2) to a power-generating ground station (3). The flying craft will be approximately 8 feet across and weigh about 15 pounds. It will fly between 200-500 feet above the ground and will be tethered to the ground station by use of a nylon or steel rope. At the ground station, the rope will be wrapped around a steel drum/cylinder with an electrical generator attached to the drum axle. Figure 1 shows the basic flying motion of the system and how it generates electricity. The flying craft does figure-8s as it is blown downwind (step 1), pulling out the tether and spinning the drum and electrical generator. When the tether is fully extended (step 2), the airborne craft glides back to the start of its power cycle (step 3), while the ground station simultaneously winds up the tether and the process is repeated (step 4). Additionally, this entire system will be completely autonomous, requiring no attention or effort from the farmer.Although there are other companies pursuing airborne wind energy, most are focused on utility-scale electricity generation that will not be feasible for small farmers. At eWind, we focus on smaller systems that are specifically tailored in cost and capacity to the needs of small farmers. We are also compliant with current Federal Aviation Administration (FAA) regulations, which require tether flags, lighting, and an altitude limit. Other airborne wind energy companies are attempting to receive complicated waivers or rule modifications.
OBJECTIVES: The goal of eWind Solutions is to create a wind energy system for small farmers that is efficient, affordable and easy to use. We accomplish this by using a novel way to collect the stronger, faster, more reliable winds found at higher altitudes that are inaccessible to wind towers that small farmers can currently afford. Because we intend to directly compete with traditional wind turbines, it is instructive to highlight the technical background of wind energy in general and to then discuss how our approach differs from existing wind-power technologies.It is important to remember that the specifications of the flying craft are actually secondary to the overall goal of the entire system. Thus, our overriding goal is to provide 40,000 kWh to the small farmer over the course of a year because that is what actually creates value for our customer. As the research into the tether diameter showed, when a particular attribute is (nominally) beneficially improved, it can actually reduce the power of the overall system. Therefore, we will be listing specific tensions and specifications we currently believe will be sufficient to achieve our overall goal. However, we will modify those specifications if necessary, while maintaining a focus on our power production goals. This Phase II proposal has technical objectives that should take the flying craft development to a state that is commercially viable. This will require the final physical design of the flying craft and near completion of the autonomous flight control system and software. We propose technical objectives for Phase II:Group I:Generate enough tension while the tether is reeled out to generate 40,000 kWh annually (at a good wind resource location).1) A peak force of 3.8 kN on a static tether at 9 m/s wind speed2) A peak force of 2.1 kN on a static tether at 7 m/s wind speed3) Maintain existing maneuverability accomplishments (<20 m turn radius)4) Continue to improve our software analysis capability to include more advanced CFD (computational fluid dynamics) packagesGroup II:Transition the control of the flying craft from mechanical means to fully electronic ground-based signals (fly-by-wire), to computer controlled and then autonomous crosswind flight.1) Stepwise progression from human fly-by-wire control to computer control (using a static tether length) a) Fully human controlled via electronics only (fly-by-wire) b) Computer controlled stable stationary hover c) Computer controlled side-to-side drift motion (slow and with small angle deviations from the vertical) d) Computer controlled side-to-side motion (directed and with turns) e) Automated guidance for figure-8 crosswind turns2) Fully automated crosswind flight: follow power production path put out by computer3) Repeat objectives II:1 and II:2 while actively reeling out tether (at increasing speeds)4) Stretch goals: Time of flight under autonomous control a) 5, 10, 30, 60 minutesGroup III:Determine reliability requirements and incorporate safety aerodynamic characteristics.1) Use reliability growth curve analysis to track progress and use research progress and financial considerations to determine reliability thresholds/goals.2) Introduce aerodynamic, weight and structure characteristics into the flying craft design that when control is lost, the craft enters a safer flat spin and settles to the ground at a reduced speed.The first group of objectives remain similar to Phase I, and as noted before, the work on them is on-going. Now that they have been validated with our mathematical model, they remain acceptable tension goals. Again, if we do modify them, they will continue to support our power production goals, the cornerstone of our commercial viability. We will also continue to upgrade our aerodynamics design software pipeline. Notably, this will include replacing our current XFLR5 package with a more advanced CFD suite. The second group of objectives is based around the transition from human controlled flight to autonomous flight. Based on our research, current progress and discussions with experts, we believe these are good markers for a continuous progression to this goal. It is worth noting that these goals represent a progression of increasingly complex control objectives. Essentially, we need fully autonomous flight and the progression to that goal will be a spectrum of improvement. Initially, these objectives will be met with a static tether length (neither reeling out nor pulling in). Once completed, we will increase the difficulty by allowing the tether to reel out in a manner similar to the power generating cycle. It is expected that the faster the tether reels out, the harder the autonomous control will become due to the increased likelihood and severity of perturbations of the flight path from wind gusts and tether tension oscillations. These tests will gradually increase the tether reel out speed until it exceeds the expected speed necessary to maximize the power generation of the system (approximately 1/3 the wind speed). Finally, we must address the time duration of flight. In many respects, we actually expect this to be both easy and difficult simultaneously. To clarify, to achieve the objectives in Group II we must maintain flight for at least several minutes to demonstrate the success of each milestone repeatedly. If wind and weather conditions are stable during that time, longer flight times are relatively easy. However, the longer the flight lasts, the more likely it is that something will change with the wind and/or weather. It is those transitions or perturbations that will cause the greatest difficulty in extending our autonomous flight time. It is also the hardest to test and plan for because you have to find a stable wind condition, start flying and then have the wind be courteous enough to get mildly unpredictable so that you can test the responses of the flying craft. (It should also be noted that a parallel SBIR Phase I submission would develop the tension control system that would help mitigate these effects during the testing process.) That difficultly will likely lead to an extended time that we will have to work on 'fringe' flight conditions. Thus, we have decided to place flight time duration as a "stretch goal" for this grant. As part of Group III, we must determine how reliable the flying craft must be. To that end, we will employ reliability growth curve analytics. Our prototype testing will provide the necessary reliability/failure data. Additionally, we must determine the failure rate goal. While we obviously do not want the commercial flying craft to ever fail, it is inevitable that it will at some point. Assuming that these failures damage the craft and require a repair visit, we need to balance the economics of that with the time and money in research and development necessary to increase the reliability, at least in the short-to-medium term. This reliability growth curve analytics study will help us manage both the cost of the craft and its field reliability in preparations for commercial use. Thus, one of the more important goals of the Phase II proposal is determining the necessary reliability of the flying craft. Additionally, we will incorporate design elements into the flying craft that will minimize the impact of these failures. For example, we are currently shaping the system to enter a "flat spin" when tether tension/control is lost. This state puts the flying craft horizontal to the ground and allows air drag the maximum amount of time to bleed velocity and kinetic energy before it lands. Currently, this helps us preserve prototypes, but when commercialized it will increase safety and reduce damage during flying craft control failures.
APPROACH: Task #1: Design, analyze, optimize, build and test a flying craft that can match the tension and maneuverability requirements of 40,000 kWh (Group I objectives) (Months 1-24). As previously described, the focus of the entire research and development effort within this SBIR proposal is to create a flying craft capable of creating enough tension in a tether that can be converted into 40,000 kWh of electricity. This task will be carried out by founders P.I. David Schaefer and Dr. Brennan Gantner, with the help of the expected two new employee hires. The research and development process will be similar to the work of Phase I. We are continuing to refine the university collaboration mathematical model (using an Oregon BEST grant, see Commercialization Plan). The lessons and refinements of that knowledge are then folded into new designs built in our aerodynamic software package (currently XFLR5). These designs are imported into our CAD (computer aided drafting, Autodesk) software, split into parts and individual pieces are created via 3D printers, machined by a CNC router and foam hot wire molds. The prototype is then built/assembled. Tests consist of flying the prototype in a relatively steady wind for as long as possible/needed. During that time, our custom equipment is continuously measuring the tension generated on the tether and the Pixhawk/Labview software/electronics is tracking velocity, orientation and location (as well as temperature, air pressure, wind speed/direction, etc.). Currently, we typically conduct these tests on the Oregon coast. Not only does this area have reliable winds, but the loose sand provides reasonable cushioning during control failures and minimizes damage to the prototype. We are investigating the possibility of also using the FAA designated drone testing area at the nearby Warm Spring reservation. While we do not legally need FAA exceptions/permission this area provides, it does allow us to forgo some of the visibility requirements for higher/longer tests on a temporary basis.Task #2: Transition the control of the flying craft from mechanical means to fully electronic ground signals (fly-by-wire), to computer controlled and then autonomous crosswind flight (Group II objectives) (Months 1-24) Founder Sean Mish will lead the effort to automate the flight of the flying craft. After optimizing the CFD software system, Dr. Gantner will transition to contributing to the automation task. As discussed, this will be a spectrum of improvement that will slowly transition control away from direct hand/mechanical links to a flying craft controlled completely by a software/electronic servo system. While this is technically a separate task from the aerodynamic design, Mr. Mish and Dr. Gantner will continually contribute and add requirements to the flying craft design. Because the computer control aspect of the flying craft is mandatory, we have determined that it is most efficient to not only advance the automation concurrently with the aerodynamic design, but to immediately incorporate its needs and lessons into the current prototype. For example, if the computer response time is slow to correct for an unanticipated turn than a human, it may need larger or more aggressive turning control surfaces to compensate. This requirement needs to be known to the aerodynamic design team so that these enhanced control surfaces can be incorporated into the latest design. This task will begin with the attempt to have the computer hold the flying craft stationary on a static length tether. Our initial work suggests that the Pixhawk controller and its corresponding open-source control software is capable of completing these tasks. At its core, it is designed to take a radio-controlled hobby plane and turn it into a computer controlled drone. We essentially want to do something similar, but with a different default orientation (perpendicular to the tether instead of gravity) and different physical responses to the standard commands (it likely won't have airplane standard ailerons, rudder, etc.).Therefore, a large portion of this task will be the modification of this open-source software to our specific needs. To this end, we are initiating a collaboration with Dr. Christopher Lum, who runs the Autonomous Flight Systems Laboratory at the University of Washington. His lab specializes in drone control systems and several of his students have worked on very similar control system modifications of Pixhawk software. Once we had modified the Pixhawk software to our flying craft, we will begin to transfer control to it. As stated, the first task will be to have it hold the flying craft stationary in the sky. Once it can reliably do that, we will have it create side-to-side motion, likely by having it make small orientation changes that creates a slow drift to one side, followed by the opposite motion in the other direction. The key to this progression will be the ability of the system to return to a stationary or 'resting' position as quickly as possible. To succeed at these steps, the Pixhawk will have to demonstrate that it can move the flying craft in the desired direction and stop that motion as needed. These tests will increase in difficulty by increasing the orientation angle from vertical (see Figure 13) that the Pixhawk is allowed to turn the flying craft, thus, increasing the speed of the side-to-side motion. Essentially, true side-to-side or figure-8 flight will be achieved when this angle is increased to (or above) 90 degrees; when it is pointing horizontally.Task #3: Determine reliability requirements and incorporate safety aerodynamic characteristics (Group III) (Months 1-24). Task #3 will be run by P.I. Schaefer, who has decades of experience in these types of product development cycles. Reliability growth curves track the improvement of reliability of the system. One of the key ingredients of properly using them is having a meaningful reliability goal to achieve. In this case, that goal will be a balance of costs based on the value of the flying craft and the cost of replacement (time, travel, materials, etc.) versus the rate of flight time improvement per dollar spent in research and development. This task is a combination of financial considerations balanced with hard data of reliability gathered from prototype testing. To accomplish this, each failure mode will be tracked and rated on severity, likelihood, detectability and consequences. These measures will then be combined (Risk Priority Number (RPN)) to determine the most severe failures so that efforts can be directed to mitigate those cases. This process is a standard approach to product development. While this work will cover the full grant duration, its efforts will ramp up significantly during the second half.
M 21997   Feb 18, 2017   Dave Santos
Pixhawk Autopilots
eWind teamed up with University of Washington’s Department of Aeronautics and Astronautics to adapt the Pixhawk for AWES use.

Looks like a nice low-mass drone controller from open-source culture. We have reviewed various active-control options (Kestrel, NI/smartphone, Arduino, Silicon Labs microcontrollers, etc), and will no doubt find more emerging.
Home - Pixhawk Flight Controller Hardware Project
21461    Dec 9, 2016   Dave Santos
Re: [AWES]      eWind media coverage on its team and challenges


A photo from last year of one of the "forty prototypes"-



On Friday, December 9, 2016 4:42 PM, "dave santos santos137@yahoo.com [AirborneWindEnergy]" <AirborneWindEnergy@yahoogroups.com> wrote:

Beaverton tech startup takes kite flying to new heights


By Rick Arnett
A Beaverton tech startup has designed a new system that can produce up to four times more energy than comparable...