Worcester Polytechnic Institute is at the forefront of developing tiny drones designed for search and rescue missions, particularly in challenging conditions such as darkness or storms. In a robotics lab filled with fog machines and artificial bats, researchers are testing these innovative aerial robots, which draw inspiration from the echolocation abilities of bats.
Nitin Sanket, an assistant professor of robotics engineering, explained the motivation behind this project: “We all know that when there”s an earthquake or a tsunami, the first thing that goes down is power lines. A lot of times, it”s at night, and you”re not going to wait until the next morning to go and rescue survivors.” This prompted the team to explore whether any natural creatures could navigate in such conditions, leading them to bats.
With support from a grant from the National Science Foundation, Sanket and his students are creating small, cost-effective, and energy-efficient drones that can be deployed where traditional drones might fail. Recent real-world applications of drones in rescue operations, such as locating flood victims in Pakistan and assisting trapped individuals in California, highlight their growing importance in emergency responses.
However, as the use of drones in these scenarios becomes more common, experts like Ryan Williams from Virginia Tech emphasize the need for autonomous drone systems. Williams is focused on enabling drones to operate in swarms and make independent decisions about their search patterns. His team has utilized historical data from missing person cases to refine the drones” search strategies, significantly enhancing their efficacy.
At WPI, Sanket”s research also aims to overcome existing limitations of drones, including their size and sensory capabilities. Unlike current models that are bulky and expensive, the new drone is compact enough to fit in the palm of a hand, constructed mainly from affordable materials, and capable of functioning in low visibility settings. It employs a small ultrasonic sensor that mimics bat behavior, emitting high-frequency sound pulses and interpreting the echoes to navigate around obstacles.
During a recent demonstration, a student successfully launched the drone in varying lighting conditions, showcasing its ability to halt and reverse when approaching barriers, even in complete darkness and amidst artificial fog and snow. “Currently, search and rescue robots are mainly operational in broad daylight,” Sanket acknowledged, pointing out the need for drones that can operate effectively in more hazardous environments.
Despite the progress, challenges remain. Researchers discovered that the noise generated by the drone”s propellers interfered with the ultrasonic signals, necessitating the creation of 3D printed designs to mitigate this issue. Artificial intelligence is being integrated to enhance the drone”s ability to filter and interpret sound signals. While significant strides have been made, Sanket admits that they have yet to achieve the level of sophistication found in bats, which can selectively listen to certain echoes and detect minute objects from considerable distances. “Bats are amazing,” he remarked. “We are nowhere close to what nature has achieved. But the goal is that one day in the future, we will be there, and these will be useful for deployment in the wild.”
