Tethys Robotics is an ETH Zurich spin-off that develops underwater drones. These small submersible robots are used, for example, on inspection dives at hydropower plants, to recover ordnance or in searches for people and objects.
Picture: Tethys
Machine-aided underwater exploration is nothing new; submersible robots have been around since the late 1950s. The images of the Titanic, which show the interior of the wreck lying at a depth of around 3,800 metres, have been etched into our collective memory by the eponymous film. The Japanese submersible robot Kaikō’s dive to the deepest point of the Mariana Trench in 1995 was just as spectacular.
Most conventional submersible robots are actually quite large and have to be lowered into the water by crane. Such submersible robots are far too big for dives in smaller or less deep waterbodies, such as lakes and rivers, or at shipyards. The alternative of using human divers is expensive and risky, especially when conditions are challenging.
Start-up company Tethys Robotics is currently developing a small submersible robot. It is 75 centimetres long, 50 centimetres wide, weighs 39 kilograms and looks much like a drone. As GPS signals do not work underwater, the underwater drones from Tethys Robotics are equipped with a camera and sonar as standard; this allows them to see in the water and to locate objects or creatures, such as dolphins, by emitting acoustic pulses. The system is modular, so tools and sensors can be mounted as required.
“We deliberately focus on keeping the underwater drone compact,” Jonas Wüst, CEO of Tethys Robotics, points out. “Just ten years ago,” he adds, “it was still impossible to build such small autonomous submersible robots. Back then, the robots weighed a few hundred kilograms. Due to its low weight, our submersible robot can be operated by one to two people. The size of our robots gives them the advantage of also being able to operate in artificial lakes and reservoirs, or in rivers like the Limmat or the Aare.”
Thus, such robots can be used for dives that were previously restricted to humans, such as ordnance recovery. Other possible applications include searches for people or objects, as well as infrastructure inspection and maintenance – which can include, for example, cleaning gratings or pumps by removing seaweed or branches. “As a robotics start-up,” says Jonas Wüst, “we have lots of ideas about where our submersible robots can be used. However, we are currently in the process of defining our specific business case.”
Artificial intelligence (AI) is now used as standard in robotics, and the underwater drones from Tethys Robotics are no exception. On one hand, AI aids navigation: Not only does AI make the sequence of movements in complex manoeuvres easier to implement, it also delivers more elegant motion than conventional algorithms. Furthermore, AI is used in downstream processing of measurement points, for instance to create a 3D model of a space that the robot has inspected. Here, the measurement data from the sonar is combined with images from the camera or data from other sensors. It takes around one hour to create a three-dimensional image of a space measuring ten by ten metres.
Unlike some other start-ups, robotics companies face high costs: It is not enough to just develop robots, they also have to be built, which requires more spending on materials, as well as on human resources. In addition, many components for underwater drones are more expensive to obtain than comparable components for terrestrial robots.
For several months now, Tethys Robotics has been based at the Wyss Zurich Translational Center, a multidisciplinary environment that it benefits from in terms of not only financial support, but also access to infrastructure and experts. However, the firm is equally embedded in the robotics start-ups ecosystem. This brings numerous advantages because other start-ups are facing similar challenges. Jonas Wüst puts it as follows:
“As very few start-ups compete directly with each other, exchanges within the robotics environment and with colleagues from other companies are very valuable, and have already yielded crucial information in some areas. There are also initiatives that promote exchanges, such as Swisscom Ventures and the ‘AI and Robotics’ platform. Such exchanges are worth a great deal to us; it helps when people from similar fields come together and discuss solutions.”
