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We develop underwater robots to tackle tasks in challenging environments, focusing on omnidirectional manoeuvrability, modularity and easy deployability.
The underwater world is a challenging and dangerous environment. Every day, human lives and sensitive equipment are put at risk during search and rescue operations, commercial exploration, inspection and construction, and oceanographic research. That is why we, Tethys Robotics, are developing Unmanned Underwater Vehicles (UUVs) as a solution to support professionals perform their tasks safely, reliably and efficiently.
To date, there are absolutely no solutions to safely perform stationary tasks in high-current waters such as rivers, since control and navigation under these conditions are highly challenging due to abrupt changes in water conditions regarding flow velocities, turbulence and visibility. Navigating a UUV in this environment requires accurate, low-latency, and high-frequency pose estimation using several sensor systems to guarantee safe operation at all times.
To specify even more, despite the variety of possible underwater tasks around the globe, one of the biggest challenges, besides the problems that occur in strong currents, remains general underwater navigation and localization. Unlike flying vehicles, underwater vehicles cannot rely on conventional Global Navigation Satellite System (GNSS) technology because the required electromagnetic waves cannot penetrate deep enough into the water. Likewise, typically used vision sensors cannot be relied upon because visibility is not guaranteed. To overcome this navigational problem, acoustic-based devices are commonly used to determine the position of a UUV. The necessary underwater positioning sensors deployed in the industry are baseline systems (e. g. USBL, SBL, LBL), where several transponders with fixed, known positions are used to estimate the position of one or more mobile transponders through acoustic ranging. Additionally, vehicle based-sensors such as Doppler Velocity Loggers (DVLs) can be used to measure the vehicle’s relative velocity above ground. However, these systems and their implementations are mainly designed for open ocean applications, where the environment is not as turbid and cluttered as in lakes and rivers.
In these waters, the high particle density and turbidity, the correspondingly poor visibility and the usually limited operating area (i.e. harbour areas, river estuaries and underwater valleys) are the reasons why conventional UUVs, which rely on these acoustic sensors in combination with cameras, do not function as reliably as they do in the open ocean.
This is where we want to differentiate ourselves in the market by offering relatively low-cost and easy-to-use unmanned underwater vehicles with precise localization that allows us to perform semi-autonomous tasks under all the above-mentioned conditions. To offer these capabilities that are either traditionally reserved for much larger and/or more expensive systems or do not yet exist at all (e.g for strong currents applications), we leverage the history of core research in the navigation of aerial vehicles at ETH Zürich and extend it to the underwater domain. We use especially evaluated acoustic sensors, our unique knowledge regarding navigation in turbid and cluttered areas and an innovative approach to sensor fusion to operate our small and lightweight UUVs in a wider variety of conditions than what exists today.
Visit us at RobotX 2022! This year we will take again part in the RobotX exhibition at the ETH. The event will take place on the 1. July 2022 at the historic ML hall of the ETH. For more information, please visit the official webpage.