Imagine a quadcopter drone flying with some propellers unable to rotate, how can it still maintain safe flight? The research team of Beihang University has made significant breakthroughs in fault-tolerant control technology for multi rotor unmanned aerial vehicles after years of research, and has found answers to the above problems. The relevant achievements were recently published in the IEEE Journal of Robotics, an important international academic journal in the field of robotics. The picture shows a photo of a quadcopter drone operating with only one propeller in flight. (Image provided by scientific research team) Industrial inspection, fire rescue, package delivery, photography and videography... Drones have penetrated into the production and daily life of the public. Common types of micro unmanned aerial vehicles include multi rotor, fixed wing, helicopter, etc. Among them, multi rotor unmanned aerial vehicles are currently one of the most widely used aircraft, which provide lift through multiple propellers and have vertical takeoff and landing and hovering capabilities. However, when drones are rapidly becoming popular, there are often situations where extreme weather conditions, collisions with obstacles, etc. lead to strikes and ground crashes, resulting in losses of people and property. How to improve flight safety has become an urgent issue in the industry. (Reporter Zhao Xu) The reliable flight control team of the School of Automation Science and Electrical Engineering of Beihang University has conducted research on quadcopter unmanned aerial vehicles and successfully designed a passive disaster recovery control algorithm based on the force characteristics of the aircraft's actuator after sudden failures. The team found through experimental verification that the "control brain" of quadcopter drones equipped with this algorithm can maintain safe flight and achieve controllable return even if three propellers fail. Dr. Ke Chenxu, a member of the team and a member of Beihang University, said that the relevant achievements can be expanded and applied to multi rotor unmanned aerial vehicles such as six rotor and eight rotor. The figure shows the flight dynamics of a quadcopter drone with only one propeller operating (0.1 times the speed). (Image provided by research team) If some of the propellers fail, the overall balance of the drone will be disrupted, and the fuselage will rotate like a gyroscope, causing the propellers to "revolution". With this phenomenon, our algorithm can make the normally running propellers "clone" and provide all the lift - it's like playing table tennis. If a person moves fast enough, they can serve and run to the opposite side to catch the ball, and so on, completing a person's journey back and forth "The ball game." Professor Beihang and members of the team have full authority to speak. Quanquan stated that in the future, this achievement will be applied to the development of new multi rotor unmanned aerial vehicles, improving their flight safety performance. The reviewers of the IEEE Journal of Robotics commented that the innovative use of passive disaster recovery control algorithms in this study is expected to provide reliable references for scientific research in the field of drone flight safety. (Lai Xin She)