The first generation of the ARGO underwater drone is presented at the IDET International Defence and Security Technologies Fair by students of Brno University of Technology. The strojLAB team, which brings together students from across faculties and disciplines, is working on the construction of a small submarine with which it wants to explore and perhaps even reach the bottom of the Hranice Abyss. After a year of development, students have finished the first model, on which they test the intended design elements, special drive and control. ARGO can be seen from 24 to 26 May at the BUT stand, Hall P, stand no. 110.

"I got the idea for a submarine for the Hranice Abyss last year at the end of the exam period. At the time, I was reading an article about another attempt to reach the bottom of the abyss and it occurred to me that we might try to design and construct our own submarine. Of course, we cannot be sure if we succeed or if we actually reach the bottom of the abyss, but that is not what our team is about. The goal is for us to learn as much as possible from the project and for every member of the team to find an area that they will find interesting and entertaining," says Jan Kalina, head of the strojLAB student team.

The Hranice Abyss is located in the Hranice Karst in the Olomouc Region. The depth of the dry part of the abyss is 69.5 meters. At the bottom there is the Hranice Lake, which covers the flooded part of the abyss, the depth of which has not yet been fully established. In August 2022, a record depth of 450 meters below the surface was reached, but even then then the bottom was not reached. The Hranice Abyss is the deepest flooded freshwater cave in the world.

According to Kalina, the submarine – or underwater drone, as ARGO is called by the students – was a sufficiently ambitious project, which also offered the possibility of involving students across BUT. Although the team is based at the Faculty of Mechanical Engineering, it already includes a group of young chemists who plan to deploy a water analysis module at ARGO, computer science students working on software and students from the Faculty of Business and Management take care of sponsors and marketing. About twenty-five students are currently working on the design and development of the submarine.

A cylinder about a meter and twenty long does not weigh much yet, on land it is between two and five kilograms. For the first phase of testing, ARGO is largely made of 3D-printed plastic. At one end, the submarine carries cameras and sonar, and at the other, a cable that powers and controls it. And – perhaps surprisingly – water deliberately leaks into the submarine. "It's designed in such a way that its interior is flooded with water and our drive and the 'brain' of the whole submarine are in pipes that pass through its body. It is structurally simpler than dealing with waterproofness," explains Tomáš Jakuš, a student of the Faculty of Mechanical Engineering, who is in charge of the simulation development team.

The mentioned drive is quite rare. The students opted for the so-called rim-thruster, an innovative type of electric motor that the layman can recognize at first glance by the fact that its blades are not located on the central shaft, but on the outer ring. "So far, we are trying to get closer to the real rim-thruster, and we selected this drive for a reason. A number of previous dives had failed because the submarine's cable got tangled. Thanks to the rim-thruster drive, we should avoid this danger," adds Jakuš, adding that the use of this drive for an underwater drone is quite unusual, the rim-thruster is still used more in sea transport.

To control the submarine, the team modifies commonly used software designed to control flying drones. "Our underwater drone is a bit similar, but we still have to modify the software a lot. After all, movement under water is spatially more complicated and also slower than in the air. We are also planning partial elements of autonomous driving and we are also preparing our own user interface and controller that the pilot will use," said Tomáš Svoboda, coordinator of strojLAB projects.

The submarine’s design is modular. The aim is to make it easy to fit it with the necessary equipment of various types and thus change its purpose. In the meantime, students plan to work on 3D mapping of the environment, water and sediment sampling, or rock sampling. The submarine team has already applied for the BUT Student Entrepreneurship Award, thanks to which they had the opportunity to demonstrate ARGO at this year's IDET fair. "The jurors in the competition advised us that a number of elements from our submarine can be quite innovative and interesting, for example, to be used by the army or the police," says Vojtěch Parkan from the team's business section.

At the BUT at IDOS fair, also the following FME exhibits can be seen: · Fire platform APP30 (FSI, Department of Production Machines, Systems and Robotics) · Underwater drone ARGO (FSI, strojLAB) · Demonstrator of semi-active damper function (FSI, Department of Design) · OpenTube2: robotized workplace for handling potentially infectious biological samples · (FSI, Institute of Automation and Informatics) · Part of the BUT exhibition is also a distinctive front panel with the university logo, · which was created using 3D printing by colleagues from the Institute of Design FSI. More about BUT's participation in IDET can be found here.

The so-called first development stage, which will be completed by ongoing tests, aims to check whether students have chosen the right type of construction and that the selected drive does not represent a dead end. "If all goes well, we would like to have phase two ready at the beginning of the next year. It will be a more solid design, many components will not be made of plastic, but of metal and the systems will be more sophisticated. The ambition of stage two is to dive ARGO into the Brno dam. There, due to the depth, it will have to withstand higher pressure, the water will be murky and the movement will be more complicated. It will no longer be about laboratory conditions," concludes Parkan.

strojLAB is an inter-faculty team of BUT students, which aims to work on unique projects that students would not dare to do on their own. It offers students the opportunity to participate in the development of the device from the very beginning. The team is based in the student workshop strojLAB at the Faculty of Mechanical Engineering, but also uses other laboratories across BUT. www.strojlab.cz team website