Recovering a Drone After Total Rotor Failure

What happens when a rotor on a drone fails? Usually, the drone becomes erratic and puts itself at high risk of collision. Sihao Sun talks about his award-winning research which creates a control module that is able to control the drone in this critical state.
His research takes in real-world scenarios where the drone likely has a rotor failure because it actually collided with another object. Many other research projects in this space assume a random rotor failure where there are no other obstacles near it (walls, other drones, etc.)