An Efficient Rotation Strategy for Quadrotor Recovery Using Feasible Attitude Trajectory Design Pohang University of Science and Technology

Abstract

When a quadrotor experiences being thrown or encounters a collision situation, it may encounter unpredictable aggressive attitudes and angular velocities. In response, a robust attitude recovery process becomes essential. Previous studies have utilized regulation methods that use attitude error from initial attitude to upright attitude for attitude recovery. Nevertheless, these methods may fail in recovery to a hovering state in extreme situations, especially when faced with significant angular velocities oppos- ing the recovery direction. To address these challenges, we propose an attitude tra- jectory method aimed at achieving stable attitude recovery under extreme conditions. This method provides the quadrotor with a feasible and guaranteed attitude trajectory, considering factors such as initial angular velocity, initial attitude, and physical con- straints of the quadrotor. Also, we generated trajectories for long and short directions in order to efficiently recover attitude in a broader range of situations. Furthermore, we introduce an algorithm to determine the optimal recovery direction based on fallen height considerations. Simulations and experiments using a real quadrotor show that the proposed recovery approach enables stable attitude recovery for the drone in many abrupt situations.