# Development of a Mobile Buoy with Controllable Wings: Design, Dynamics Analysis and Experiments
The traditional profiling buoys are capable of conducting vertical profiling observations by sinking and floating, but lack the ability to move horizontally, and can only drift with the waves. The underwater glider, such as Spray [19], Slocum [20] and Seaglider [21], is an automatic underwater vehicle that moves vertically by changing buoyancy and horizontally using wings. It can conduct observations in a long range, but it lacks the ability to perform vertical profiling observations. If the positive attributes of multiple autonomous surface/underwater vehicles can be combined, then the multifarious and continuous observation of ocean can be achieved. Recently, the field of cooperation observation by multitype vehicles has emerged, changing the status of vehicles with a single mode and satisfying the needs of comprehensive observation [22; 23]. Given that the motion of Argo profiling buoys is uncontrollable, while the underwater glider observations can be planned, a combination of Argo profiling buoys and underwater gliders is proposed to perform network sampling of the ocean [24]. However, the implementation of multiple types of vehicles working together in one system poses a significant challenge to the control capabilities of the system. In addition to the above approaches, researchers have tried to explore underwater vehicles with multiple motion capabilities. For example, a multimodal underwater vehicle with a specially designed attitude control system and ingenious general arrangement that allows switching between buoying and gliding modes [25]. [PERSON] et al. [26] presented a conceptual design of a multimodal underwater vehicle carrying a propeller/rudder to correct the heading deviation caused by the mode transition. Then, a mathematical model that can fully describe the two operation modes is established based on the quaternion method, revealing the deviation of the heading angle in the switching between Argo mode and zigzag gliding mode. [PERSON] et al. [27] proposed a dual-modal vehicle named Petrel-Dual, which can navigate in different modes on the surface and underwater. This vehicle has the ability to convert the harvested wind energy into a propulsion force for surface navigation, and can be pushed by diving or climbing in underwater navigation by its own net buoyancy and hydrodynamic lift. Multimodal underwater vehicles certainly contribute to ocean monitoring by providing a large amount of data collected from different locations. The harmonious integration of different underwater vehicles into a single well-functioning system poses a great challenge for the associated theoretical analysis and control. A dynamic model is essential to analyze the dynamic characteristics of underwater vehicles. With the advent of high-computational computers, dynamic models of gliders have been rapidly developed. [PERSON] et al. (2018) established a six-dof (six degrees of freedom) parameterized dynamic model of the Petrel-L glider and explored the effects of wing location and net buoyancy on turning maneuverability and gliding stability. [PERSON] et al. (2019) developed the dynamics model of gliders using dual quaternions to solve the \"gimbal lock\" problem caused by the increased pitch angle range, which furtherly enriched the motion modes of the glider. The effective dynamic model is crucial for evaluating the motion response and stability of marine buoys. [PERSON] et al. (2020) considered the influence of sea water density variations and developed a nonlinear dynamic model for deep-sea profiling buoys, which provides a theoretical foundation for effectively controlling the vehicle. [PERSON] and [PERSON] (2020) considered the dynamics of the cables and buoy in the numerical model and established the model of the buoy by numerical integration algorithms, aiming to illustrate the relationships between these motions and the propagating waves. In the research process of underwater vehicles, accurate hydrodynamic analysis is essential for dynamic modeling and motion performance analysis.