Heave Motion Estimation from IMU measurements in Hybrid Aerial-Amphibious Drones and Horizontal Take-Off Window Prediction

Employing hybrid aerial-amphibious drones, for activities in the marine environment, comes with a series of challenges that concern managing the interaction between the robot and the water surfaces, especially in the presence of waves. This paper focuses on the take-off transition from water to air, aiming to identify and predict those time windows in which the drone has a close to zero roll and pitch (horizontal attitude) and the propellers are the furthest from the water surface, thus optimizing the take-off. The proposed solution merges the measurement of the drone vertical displacement, due to the wavefronts, with the attitude data, returning a prediction signal that marks the best take-off windows in the immediate future. The idea has been validated through numerous simulated case studies.