Engineering news
Researchers at the University of Illinois have developed a self-contained robotic bat with soft, articulated wings that can mimic the key flight mechanisms of biological bats.
Bats have interesting agility and maneuvering characteristics, achieved by functionally versatile dynamic wing conformations as well as more than 40 active and passive joints on the wings, creating a musculoskeletal system that can change shape and is capable of movement in multiple independent directions. However, their wing flexibility and complex wing kinematics pose significant technological challenges for robot modelling, design, and control.
Soon-Jo Chung, an aerospace professor, said: “It possesses a number of practical advantages over other aerial robots, such as quadrotors. We reduced the number of joints to nine, five active and four passive. The compliant wings flap at lower frequencies so are inherently safe, because their wings comprise primarily flexible materials and are able to collide with one another, or with obstacles in their environment, with little or no damage.”
The 93g robot utilises a morphing skeleton array and a silicone-based membrane skin that enables the robot to change its articulated structure in mid-air without losing an effective and smooth aerodynamic surface, according to the researchers.
Alireza Ramezani, a PhD researcher at the Coordinated Science Laboratory at the university, said: “Its morphing property cannot be realised with conventional fabrics. Non-stretchable materials resist the forelimb and leg movements. As a result, we covered the skeleton of our robot with a custom-made, ultra-thin membrane that is designed to match the elastic properties of biological bats’ membranes.”
Bat-inspired aerial robots also bring significant improvements in energy efficiency over current aerial robots, according to the university. This is partly due to their articulated soft wing architecture, and the fact that wing flexibility amplifies the motion of the robot's actuators. The robot does not use high-speed rotors that emit loud, high-frequency noise, so is less intrusive than quadrotors or other aerial robots.
One potential application of the robot is to supervise construction sites, by having the ability to be stationary and perch on structures. The robot could also fly around and compare the building information model to the actual building that is being constructed.
In addition, if the robot is equipped with a radiation detector, 3D camera system, and temperature and humidity sensors it could inspect nuclear reactors, where the radiation level is too high for humans, or fly into tight crawlspaces such as mines or collapsed buildings.
The research is published in
Science Robotics.