Researchers from Delft University of Technology have developed a swarm of tiny drones capable of autonomously exploring unknown environments. The research was presented on October 23 in Science Robotics. The new work is important for the ongoing development of swarm robotics.
One of the most challenging parts of developing these tiny robots was that in order for them to move autonomously, something needed to be done about their limited sensing and computational capabilities. The team, consisting of researchers from TU Delft, University of Liverpool, and Radbound University of Nijmegen, looked to insect navigation as a model.
As mentioned many times on this site, swarm robotics is a growing field that can lead to many possibilities. The real-life insect swarms have been used as a model for tiny robots. An individual robot may be limited in its abilities, but grouping many together can provide new capabilities. The small robots are often less expensive, and they can complete tasks that many larger ones cannot. With the use of small robotic drones acting in a swarm, disaster sites could be explored and understood much faster. This technology is not out yet, but researchers are constantly working on it because of the great possibilities.
The joint research team of TU Delft, University of Liverpool, and Radbound University of Nijmegen are financed by the Dutch national science foundation NWO Natural Artificial Intelligence programme.
One of the major areas where this technology can be used is within search-and-rescue missions. The research team developed the swarms of drones with the idea of utilizing them in such missions. If the team accomplishes what they want, rescue workers would be able to use swarms of tiny drones to explore a disaster site and report back. For example, a building on the brink of collapsing would be explored by the drones, and they would then report back with the locations of people inside.
The swarms of tiny drones could also be equipped with cameras in order to find victims. The research team tested this by sending the drones into an indoor office environment that contained two dummy victims. The experiment was a success, and a swarm of 6 drones explored 80% of the open rooms within 6 minutes. This task is not possible with just one drone.
Another advantage of having multiple small drones is that if one malfunctions and fails to bring back an image, there are several others with the same information. This was shown in the test when one drone found a victim but lost the image, and another came back with it.
Kimberly McGuire is a PhD student who worked on the project.
“The biggest challenge in achieving swarm exploration lies at the level of the individual intelligence of the drones,” says McGuire. “In the beginning of the project, we focused on achieving basic flight capabilities such as controlling the velocity and avoiding obstacles. After that, we designed a method for the small drones to detect and avoid each other. We solved this by having each drone carry a wireless communication chip and then making use of the signal strength between these chips — this is like the number of bars shown on your phone that decrease when you move away from your WiFi router in your home. The main advantages of this method are that it does not require extra hardware on the drone and that it requires very few computations.”
The hardest part of developing these tiny swarm robots is autonomous navigation. It is extremely difficult to get a group of small robots to navigate a completely unknown environment. This is the main reason the researchers turned to insects as a model; they often navigate environments without any previous knowledge of them.
“The main idea underlying the new navigation method is to reduce our navigation expectations to the extreme: we only require the robots to be able to navigate back to the base station,” says Guido de Croon, principal investigator of the project. “The swarm of robots first spreads out into the environment by having each robot follow a different preferred direction. After exploring, the robots return to a wireless beacon located at the base station.”
This new development is just one of many that are coming out of robotics. Swarm robotics is an important field that opens up many new possibilities.