German researchers have invented an aquatic robot designed to prevent drowning.
Scientists from the Fraunhofer Institute for Optronics, System Technologies and Image Exploitation (ISOB) in Germany have created an autonomous underwater robot intended to assist lifeguards rescuing swimmers in emergencies.
According to the German life-saving association, the Deutsche Lebens-Rettungsgesellschaft (DLRG), nearly 420 people drowned in Germany in 2019. Although the majority of these deaths occurred in fresh water lakes, numerous accidents also occurred in swimming pools.
Because a reason for this is a lack of trained life-guards to watch over pools, a team of researchers from the Institute for Advanced Systems Technology (AST) of Fraunhofer IOSB has developed an aquatic robot, the only one of its kind.
The project was led by computer scientist Helge Renkewitz, in close collaboration with Wasserrettungsdienst Halle e.V.
“There are typical postures that you can use to recognize when someone is in danger,” Renkewitz said.
The robot has been tested in a variety of settings including indoor pools and open water.
In an indoor pool, the robot works in coordination with cameras mounted on the ceilings. When the cameras register
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movements consistent with drowning, it sends the coordinates of the drowning person to the robot, which is stored in a docking station on the pool floor, and released by a signal from the surveillance cameras. Once the robot reaches its destination, it carries the endangered person to the surface. The robot is designed with a mechanism for keeping the lifeless person from sliding down as the robot surfaces.
When tested at lakes and other outdoor settings, drones and zeppelin systems took on the task of the surveillance cameras.
“These drones and advertising balloons can easily be fitted with cameras,” Renkewitz said.
For rescues in swimming lakes where the visibility is restricted, the underwater vehicle must be equipped with acoustic sensors instead of optical ones. Sound wave echoes can be used to determine people’s positions and orientation so precisely that the robot can autonomously head for the target person and pick them up.
This system was shown to work in practice at the Hufeisensee lake in Halle (Saale).
A 176-pound dummy was deposited at a depth of three meters. The robot then picked it up, secured it in place, brought it to the surface within a second, and carried it via the shortest route – a distance of about 43 yards – to shore, where the rescue team was waiting.
When the robot is informed of an emergency, a signal alerts the team immediately.
“The full rescue operation lasted just over two minutes. Casualties must be resuscitated within five minutes to avoid long-term damages of the brain. We were able to stay within this critical time frame without any problems,” Renkewitz said.
The current system is 90 centimeters long, 50 centimeters high, and 50 centimeters wide and looks like an underwater submersible that might be used for exploring shipwrecks. The central innovation of the system is side folding wings that fix lifeless people on a stretcher without injuring them. To bring them to the surface of the water, balloons are inflated with a total of 15 to 20 kilos of buoyancy. These floats also set up the side flaps so that a body cannot slip out.
The research team aims to make future versions smaller, lighter and less expensive and plan to model the robot on a manta ray.
A patent has already been filed for the aquatic robot. In modified versions, it can take on further tasks – such as offshore and dam wall inspections or being used to monitor the health of fish in fish farms.
“Our underwater vehicles have a very broad range of applications. For example, they are also suitable for detecting and verifying archaeological artefacts at the bottom of lakes,” researchers said.
The aquatic robot safely brings the dummy to shore. Image Credit: S.Thomas (Wasserwacht Halle)
