Underwater Motions Analysis and Control of a Coupling-Tiltable Unmanned Aerial-Aquatic Vehicle
Dongyue Huang, Minghao Dou, Xuchen Liu, Tao Sun, Jianguo Zhang, Ning Ding, Xinlei Chen, Ben M. Chen
TL;DR
The paper addresses controlling a coupling-tiltable UAAV (Mirs-Alioth) underwater by deriving Singular Thrust Tilt Angles (STTA) to map motion singularities and informing controller design. It proposes a two-channel leveling scheme with a primary attitude controller and a saturated Nussbaum-function–based auxiliary to handle control-direction uncertainty and coupling, plus a logic-switching mechanism. The approach is validated in a water tank, showing stable leveling within $\pm5^\circ$ and demonstrating that the Nussbaum function is essential for stability. This work fills a gap in coupling-tiltable UAAV control and lays groundwork for robust underwater–aerial missions with improved attitude and motion control.
Abstract
Coupling-Tiltable Unmanned Aerial-Aquatic Vehicles (UAAVs) have gained increasing importance, yet lack comprehensive analysis and suitable controllers. This paper analyzes the underwater motion characteristics of a self-designed UAAV, Mirs-Alioth, and designs a controller for it. The effectiveness of the controller is validated through experiments. The singularities of Mirs-Alioth are derived as Singular Thrust Tilt Angle (STTA), which serve as an essential tool for an analysis of its underwater motion characteristics. The analysis reveals several key factors for designing the controller. These include the need for logic switching, using a Nussbaum function to compensate control direction uncertainty in the auxiliary channel, and employing an auxiliary controller to mitigate coupling effects. Based on these key points, a control scheme is designed. It consists of a controller that regulates the thrust tilt angle to the singular value, an auxiliary controller incorporating a Saturated Nussbaum function, and a logic switch. Eventually, two sets of experiments are conducted to validate the effectiveness of the controller and demonstrate the necessity of the Nussbaum function.