• multi-body
• dynamic model
• sea state
• wave model
• Liquid Robotics
• SV3
• Wave Glider
• equations of motion
• AUV
• ASV

The Wave Glider is a new class of autonomous marine vehicles having the unique capability of converting wave energy into essentially limitless forward propulsion. The vehicle heavily relies on renewable energy: waves for producing thrust and solar energy, collected via solar panels placed on the surface platform, for on-board computing, sensor payloads, navigation and communications. These peculiarities make it particularly fitted for long-time and low-cost ocean environmental monitoring. The locomotion system is also relatively quiet due to the absence of propellers rotating in the water. This makes it appealing for applications in which acoustic sensors are used, such as area surveillance and Anti-Submarine Warfare (ASW). As a downside, the locomotion system is strongly influenced by environmental factors, such as waves, winds and water current. Having an accurate and complete dynamic model is therefore of great importance. As a matter of fact it allows to predict and simulate the vehicle behavior, facilitating the development of control systems and positioning estimation. Using accurate simulations for these tasks, instead of typical, more expensive trial-and-error field tuning, reduces the required time at-sea and simplifies the control and management of vehicle missions. In this thesis a set of six degrees of freedom (DOFs) nonlinear equations of motion is proposed. Besides, the key hydrodynamic forces are analytically formulated and a sea state-dependent thrust is finally presented. The resulting model is then validated throughout numeric simulations with Matlab&Simulink software, in which along-track and turning motion are presented under a variety of sea conditions spanning from sea state 2 (SS2) to sea state 6 (SS6), included. The obtained results are comparable to the real field ones found in the literature, placing this work as a solid base for future developments.