Machines are already capable of many things. A certain set of sensors has already been fully developed. And yet, Harald Gietler, researcher at the Department of Smart Systems Technologies seeks to discover: “Who knows what kinds of sensors we will need in the future?” He is currently developing a new technology, which will allow machines to determine the location of other machines.

Harald Gietler specialises in electrical engineering. Using electromagnetic fields, for instance, he hopes to improve the localisation of autonomous systems, such as robots or drones. Explaining the mechanism involved, he tells us: “There’s a transmitter and a receiver. Between the two, an electromagnetic field is established, which helps the receiver to determine the location of the transmitter.”

This technology could be useful, for example, in production halls where several robots are actively deployed, or in the case of wireless charging platforms, which require drones to land as accurately as possible. When asked whether there are limits to using an electromagnetic field in this way, Gietler replies: “Yes, there are limits. However, within a range of just a few metres we can provide a position determination that is precise to the nearest centimetre. What counts is this: the closer, the better.”

Under the supervision of Hubert Zangl, professor at the Department of Smart Systems Technologies, Harald Gietler is working on this topic for his doctoral thesis. In the course of his scientific career, he recently had the opportunity to spend a semester abroad at the renowned ETH Zürich, where he focused on a different aspect of the functionality of this technology. Specifically, electromagnetic fields are subject to disturbance variables, which often take the form of conductive objects, usually made of metal. “In many cases, robots are also made of metal”, Harald Gietler points out. In order to be able to deliver correct results despite these disturbance variables, their effects must be taken into account in the mathematical model. For this, attention needs to be paid to both the respective metals and the design of the robots. Due to the intensive support received at ETH Zurich, Gietler and his supervising professor were able to achieve very good results within a very short time. After returning to Klagenfurt, he now wants to process these results further. What is more, he is already preparing for a further research period abroad.

It appears that Harald Gietler, who began his studies in Information and Communications Engineering after completing the secondary technical college in Klagenfurt and who is now about to complete his doctorate, is aiming straight for a scientific career. When asked, he elaborates: “Yes, research offers many advantages. One of them is freedom. Freedom to work on whatever interests you. And, to a large degree, freedom to do that wherever and whenever you want”. Harald Gietler also enjoys teaching. Whether his path will eventually lead him to a professorship, or whether he will be tempted by a job in industry, is still wide open. “At any rate, I’m not worried,” he explains. Thanks to his goal-oriented approach to work, there is certainly no need for concern.

A few words with … Harald Gietler

What would you be doing now, if you had not become a scientist?

I’ve never really thought about it. I’d probably be a freelancer.

Do your parents understand what it is you are working on?

Possibly not in every detail, but they certainly grasp the basics.

What is the first thing you do when you arrive at the office in the morning?

Chat with my colleagues over a cup of coffee.

Do you have proper holidays? Without thinking about your work?

Absolutely.

What makes you furious?

Injustice.

What calms you down?

Sports. It allows me to forget the worries of everyday life.

Who do you regard as the greatest scientist in history, and why?

I don’t think it’s possible to name a single person. Progress is based on the work of many. If I had to choose, I would mention James Clerk Maxwell, because his work has a significant influence on mine.

What embarrasses you?

My occasional impatience.

What are you afraid of?

Obtaining unsatisfactory results from experiments that have been planned far in advance.

What are you looking forward to?

My upcoming annual surfing trip to Portugal.

Download: Harald Gietler | aau/Müller

Der Beitrag Expanding the sensory skills of machines erschien zuerst auf University of Klagenfurt.

Source: AAU TEWI

In practical settings, ten minutes of flight time are generally not enough for most applications. A team comprised of researchers from the University of Klagenfurt (AAU) and NASA-JPL/California is working on ways to enable the autonomous flight of drones in several stages with intermittent charging phases. Christian Brommer, AAU doctoral student, has recently published the results of his research.

When Christian Brommer came to Klagenfurt from California, he brought a subtle, barely noticeable American accent with him. We met him to discuss his recent publication on the autonomous and long-duration flight of helicopter-drones, also known as rotorcraft UAS. It quickly became clear that the mission time of such small drones, roughly the size of a shoebox is even shorter than one might generally assume.

The origins of Brommer’s work can be traced back to the time he spent at NASA’s Jet Propulsion Laboratory (JPL) at the California Institute of Technology in Pasadena. The department of agricultural sciences and the Robotic Aerial Mobility Group located there are collaborating on a particular study case: Rotorcraft UAS equipped with multispectral cameras are deployed to patrol agricultural land by air. It is hoped that data collected in this way will allow biologists to determine the condition of the plants. To date, this task has been performed by stationary instruments, which have a limited reach, and light aircraft, which lead to significantly higher costs.

Helicopter-drones can offer an agile and cost-efficient alternative, though they have a disadvantage due to their size. Equipped with a battery the size of a typical smartphone, these helicopters can only fly for a few minutes at a time.

The goal the research team initially set itself was to allow this process to run autonomously. During the flight, the helicopter-drone should recognize when the battery is running low and return to a charging station in a timely manner. Having arrived there, the on-board computer transmits the recorded data to a basestation while the helicopter battery is automatically charged. Once recharged, the drone should be able to take off again. Using this mission plan, a plot of arable land can be accurately surveyed in several stages.

For this sequence to work smoothly, several challenges must be faced, as Christian Brommer explains: “We need sophisticated state-estimation algorithms that provide an accurate location of the helicopter to navigate and touch down precisely on the one square metre charging platform. Markings applied to the charging platform help us to achieve this. These are recognized by a camera and allow greater precision for the navigation required during the landing phase. Our algorithms for the state estimation combine data from several sensors to determine the best possible position of the helicopter. While the navigation of drones in laboratory environments and the aid of motion capture systems are already very accurate, once we are outdoors, numerous factors such as wind, changes in air pressure or lighting conditions that affect the sensors make it more difficult to estimate an accurate location. Especially because the usual GPS positioning only allows an accuracy of about five meters.

The results of the study were recently presented at the internationally renowned IROS conference (IEEE/RSJ International Conference on Intelligent Robots and Systems) and in the Journal of Field Robotics (JFR), in a special issue focusing on agricultural robotics. Having first met Stephan Weiss at NASA’s research centre in California several years ago, Christian Brommer has recently joined him in Klagenfurt, to pursue his doctoral degree here. Brommer grew up in Werne, a small town in the northwest of Germany and is the first one in his family who pursues his PhD. “But life in the countryside also laid strong foundations for my subsequent move into technology and I could always count on the support of my family”, he told us during the interview. He studied at the University of Applied Sciences in Dortmund and then went to JPL to complete his Master’s degree. The initial 6-month contract turned into three and a half years, which had a lasting effect on him: “At JPL you have the opportunity to work with the very best in each discipline. The intensive concentration of knowledge in one place gives you the feeling of having many more opportunities to choose from.” Stephan Weiss, professor at the Department of Smart Systems Technologies at the University of Klagenfurt is widely regarded as the driving force in the area of state estimation for unmanned aerial vehicles (UAV). As a member of Weiss’s research group, Christian Brommer is ideally placed to take his next steps in the world of science.

Christian Brommer, Danylo Malyuta, Daniel R. Hentzen, and Roland Brockers. Long-duration autonomy for small rotorcraft UAS including recharging. In Proc. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2018. https://ieeexplore.ieee.org/document/8594111

Danylo Malyuta, Christian Brommer, Daniel Hentzen, Thomas Stastny, Roland Siegwart and Roland Brockers. Long-Duration Fully Autonomous Operation of Rotorcraft UAS for Remote-Sensing Data Acquisition. Journal of Field Robotics (JFR) Special Issue on Agricultural Robotics. DOI:10.1002/rob.21898

Der Beitrag Enabling drones to fly long-durations autonomously erschien zuerst auf University of Klagenfurt.

Source: AAU TEWI