Researchers at Delft University of Technology in the Netherlands have developed a lightweight tactile sensor for ultra-compact drones, inspired by the whiskers of nocturnal animals. These drones, which are used in disaster recovery efforts, often face limitations in visibility due to smoke or darkness, which can hinder their camera and lidar systems. The new sensor allows drones to navigate without visual input by using tactile feedback from the environment.
The tactile sensors consist of delicate nickel-titanium wires measuring 0.4 millimeters in diameter, with each drone equipped with two whiskers nearly 8 inches long. These whiskers contain pressure sensors that assess bending, enabling the drone to estimate its distance from nearby obstacles. All navigation calculations are processed by an onboard microcontroller.
The researchers conducted tests to determine the optimal angle for mounting the whiskers, finding that a 45-degree angle provided the best stability and orientation for the drone. They also faced challenges in filtering out false positives from sensor readings caused by the drone's own vibrations. A correction algorithm was developed to address sensor drift, reducing false positives to zero.
In controlled tests, the drone successfully navigated parallel to walls and was able to find exits in a small room with glass walls in 90 percent of trials. The researchers noted that while the tactile system is efficient, there is potential for further improvement, as it currently uses only a small fraction of the drone's memory capacity. The tactile perception system operates in real-time with minimal memory usage, demonstrating that effective tactile navigation can be achieved without compromising size or computational power.