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This paper provides a new scheme to improve the sailing distance and working time of the autonomous sailboat. The main part of the article introduces a new design of sail tug which can carry more batteries that provides more power for control system, enabling sailboats to sail longer in both time and distance. The modified sail tug was tested at an advanced test site equipped with high precision infrared motion capture system. The air curtain machines in test site can produce constant wind field, to drive sailboat steadily. Comparative experiments have been conducted to show the advantages of self-supporting ability of autonomous sail tug over ordinary autonomous sailboat.

Wing sail land-yacht is one of the promising vehicles which utilizes wind energy. However, its autonomous driving in all directions is challenging, especially the upwind steering (tacking) maneuver. This paper proposes a novel design of low cost three-wheeled land-yacht with a T-frame and a foamed wing sail, which is able to move and tack upwind owing to the lightweight design. To achieve the successful tacking, a model describing the steering process is developed based on the law of energy conservation and used to predict the minimum initial velocity for steering. In the model, an acceleration error function C induced by the environment disturbance and manufacturing error is identified by a series of experiments. Finally, the tacking experiments verify the steering model and show that the land-yacht can achieve the tacking with a high success rate of 94.7%, based on the predicted minimum initial steering velocity.

The ship wake affects the motion of Unmanned Surface Vehicles (USVs) essentially. While USV simulators have been proposed recently, they do not support the ship wake. In this paper, a computational efficient simulation of ship wake is proposed. The simulation is based on influence-point model. In some portion of the wake, this model is inaccurate. Extra processes are applied to pre-manipulate the model to ensure its accuracy. The simulation can be applied to a general scenario, especially when the ship velocity varies with time. The results show that the wake is accurate, and the computational complexity is low. The simulated wake has been equipped into a USV simulator, providing a more realistic environment disturbance.

To perform high endurance ocean cruise mission, energy is of paramount importance for Autonomous Surface Vehicles (ASVs). Autonomous sailboats, as a new type of ASV, can provide an energy-saving solution. However, conventional autonomous sailboats have low mobility in complex marine environment. Hybrid sailboat, which is equipped with an auxiliary electric propulsion system, can solve both energy and mobility problems. To achieve ocean cruise mission, the energy consumption of hybrid sailboat needs to be optimized. In this paper, the control method of the hybrid system is redesigned to address this problem. Moreover, to solve the problem of sideways drift when sailing upwind, the course stability of hybrid sailboat needs to be enhanced. This paper presents an efficient design optimization to reduce leeway angle. Notably, the leeway angle can be reduced by 55.4% and about 58.9% of energy is saved on average. Our optimization strategy can enable hybrid sailboat to sail more stable and longer.

This paper proposes an interactive system for the non-musician learners to get inspired from a song. Differing from complex models of deep learning or simple Markov models sparse of music inter-features, in this research, we unify the composing of a song in a general architecture with music theory, and thus provide a much more understandable view of the music generation for non-musician learners. The proposed model focuses on extracting the extant feature from a target song and recreating different phrases with the representing probabilistic graph underlying the target song based on the relationship among notes in a phrase. Furthermore, an interactive interface between the users and the proposed system is built with a tunable parameter for them to be involved in the music generation and creating procedure. This procedure provides practical experience in aiding the non-musicians to understand and learn from composing a song. Approximately 700 samples of preferences questionnaire survey about the generated music and original music and more than 3000 samples for interactive preferences voting for the tunable parameter have been collected. Quantities of experiments have proved the validation of the proposed system.