# Fuzzy Risk Evaluation and Collision Avoidance Control of Unmanned Surface Vessels
## 5 Conclusions  
In this paper, an integration design that integrates a collision risk indicator, a fuzzy collision avoidance act timing indicator, a collision avoidance trajectory generator, a nonlinear optimal control law and a power allocation for the real-time collision avoidance of a controlled USV is proposed. This proposed method has the potential to guide a controlled USV to take the correct evasive actions based on COLREGs rules. From the simulation results of two scenarios, which often appear in an ocean environment where the controlled USV sails, a very promising collision avoidance performance can be found from this proposed collision avoidance design with the help of the optimal collision avoidance trajectory generator and the precise trajectory tracking ability of the used nonlinear optimal control design after signals were triggered by the proposed fuzzy collision risk indicator and fuzzy collision avoidance act timing indicator. In the near future, this proposed collision avoidance method will be installed in a real developed USV with a length of 1.72 m, and the collision avoidance verification will be examined in Anping Harbor, Tainan, Taiwan. Conceptualization, Y.-Y.C. and C.-Z.W. ; methodology, Y.-Y.C. and C.-Z.W. ; software, M.-Z.E.-T. and W.-C.C. ; validation, Y.-Y.C. ; formal analysis, Y.-Y.C. ; writing--original draft preparation, Y.-Y.C. ; writing--review and editing, Y.-Y.C. All authors have read and agreed to the published version of the manuscript. This research  
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