本文為使船舶避碰行動擁有良好的避碰決策，於參考國際海上避碰規則公約，開發出有效的碰撞檢測及避碰行動。於無人船避碰檢測方式上，本研究以模糊理論為基礎開發出船舶碰撞風險指標器和船舶避碰行動時機指標器。藉此二指標器可獲得決策避碰的時機。另，本文提出一基於海上避碰規則公約之智慧型演算法進行路徑設計，並整合非線性H2控制器軌跡追蹤能力，完成無人船航行避碰之實作。其中，避碰軌跡的產生方式，於本文採用啟發式演算法並參考TCPA及DCPA推估碰撞點與避讓區，以產生最佳避碰點，再將路徑點及避碰點利用三次樣條插值法獲得避碰路徑。為了驗證本文的智慧無人船避碰系統是否具備良好的避碰效果，採用本實驗室之1.72公尺實船做為研究對象。於兩船多種避讓情境下，本文所述之智慧無人船避碰系統皆具極佳的避碰及避障效果。

A collision avoidance method is developed for autonomous unmanned surface vessels in this investigation. Practically, it is difficult to tackle the problem of collision avoidance of autonomous unmanned surface vehicle at sea with multi-ship encountered conditions. For achieving collision free missions, this collision method integrates a collision risk verifier, an optimal nonlinear guidance law, an intelligent collision free trajectory generator and a power allocation methodology for converting the guidance law into the actuators’ outputs. This is a system integration for preventing the collisions of surface vessels. Details of this collision avoidance strategy will be briefly expressed as follows: The collision risk verifier is implemented by using messages of DCPA and TCPA between the controlled surface vessel and any other moving ships. This collision risk verifier offers an effective pre alarm for noticing the controlled surface vessel to take dodge actions. Role of the adopted nonlinear optimal guidance law is to provide precise trajectory tracking ability for the controlled unmanned surface vessel to follow a collision free path which is generated via an intelligent collision free trajectory generator. As to the proposed intelligent collision free trajectory generator, it is developed for the purpose of generating a collision free trajectory. In this investigation, this collision free trajectory generator is built up based on Meta-heuristic Algorithm. Finally, a power allocation method named quadratic programming method is used to transform the desired guidance law and the actuator outputs for offering the required forces and the torques to guide the unmanned surface vessels to follow the desired collision free trajectory. From simulation results, the proposed collision free strategy reveals a really promising collision avoidance performance and an accurate trajectory tracking ability with respect to fixed objects and randomly moving targets under effect of the ocean environmental disturbances.

[1] D. Kim, K. Hirayama, and M. Okimoto, "Ship collision avoidance by distributed tabu search," TransNav: International Journal on Marine Navigation and Safety of Sea Transportation, vol. 9, no. 1, pp. 1-20, 2015.
[2] Ø. J. R⊘dseth, "From concept to reality: Unmanned merchant ship research in Norway," 2017 IEEE Underwater Technology (UT), vol. 1, no. 1, pp. 1-10, 2017.
[3] V. Konyshev and A. Sergunin, "The changing role of military power in the arctic," The GlobalArctic Handbook, vol. 1, no. 1, pp. 171-195, 2019.
[4] R.-j. Yan, S. Pang, H.-b. Sun, and Y.-j. Pang, "Development and missions of unmanned surface vehicle," Journal of Marine Science and Application, vol. 9, no. 4, pp. 451-457, 2010.
[5] N. U. S, "Navy large unmanned surface and undersea vehicles: Background and issues for congress," United States Navy, 2020.
[6] Y. Peng et al., "Development of the USV ‘jingHai-I’ and sea trials in the southern yellow sea," Ocean Engineering, vol. 131, no. 1, pp. 186-196, 2017.
[7] S. Cezary, Ś. Emilian, and S. Mariusz, "Application of an autonomous/unmanned survey vessel (ASV/USV) in bathymetric measurements," (in English), Polish Maritime Research, vol. 24, no. 3, pp. 36-44, 2017.
[8] S. Razali Chan, N. Abdul Hamid, and K. Mokhtar, "A theoretical review of human error in maritime accidents," Advanced Science Letters, vol. 22, no. 1, pp. 2109-2112, 2016.
[9] J. K. Kuchar and L. C. Yang, "A review of conflict detection and resolution modeling methods," IEEE Transactions on Intelligent Transportation Systems, Review vol. 1, no. 4, pp. 179-189, 2000.
[10] T. Statheros, G. Howells, and K. M. Maier, "Autonomous ship collision avoidance navigation concepts, technologies and techniques," The Journal of Navigation, vol. 61, no. 1, pp. 129-142, 2008.
[11] M. Salous, A. Hahn, and C. Denker, "COLREGs-coverage in collision avoidance approaches: Review and identification of solutions," 2016
[12] T. A. Johansen, T. Perez, and A. Cristofaro, "Ship collision avoidance and COLREGS compliance using simulation-based control behavior selection with predictive hazard assessment," IEEE Transactions on Intelligent Transportation Systems, vol. 17, no. 12, pp. 3407-3422, 2016.
[13] Y. Kuwata, M. T. Wolf, D. Zarzhitsky, and T. L. Huntsberger, "Safe maritime autonomous navigation with COLREGS, using velocity obstacles," IEEE Journal of Oceanic Engineering, vol. 39, no. 1, pp. 110-119, 2014.
[14] H. Lyu and Y. Yin, "COLREGS-constrained real-time path planning for autonomous ships using modified artificial potential fields," The Journal of Navigation, vol. 72, no. 3, pp. 588-608, 2019.
[15] L. Perera, J. Carvalho, and C. G. Soares, "Intelligent ocean navigation and fuzzy-bayesian decision/action formulation," IEEE Journal of Oceanic Engineering, vol. 37, no. 2, pp. 204-219, 2012.
[16] Y. He, Y. Jin, L. Huang, Y. Xiong, P. Chen, and J. Mou, "Quantitative analysis of COLREG rules and seamanship for autonomous collision avoidance at open sea," Ocean Engineering, vol. 140, no. 1, pp. 281-291, 2017.
[17] S. Li, J. Liu, and R. R. Negenborn, "Distributed coordination for collision avoidance of multiple ships considering ship maneuverability," Ocean Engineering, vol. 181, no. 1, pp. 212-226, 2019.
[18] M. Candeloro, A. M. Lekkas, and A. J. Sørensen, "A Voronoi-diagram-based dynamic path-planning system for underactuated marine vessels," Control Engineering Practice, vol. 61, pp. 41-54, 2017.
[19] R. Scheepens, H. van de Wetering, and J. J. van Wijk, "Contour based visualization of vessel movement predictions," International Journal of Geographical Information Science, vol. 28, no. 5, pp. 891-909, 2014.
[20] U. Simsir, M. F. Amasyalı, M. Bal, U. B. Çelebi, and S. Ertugrul, "Decision support system for collision avoidance of vessels," Applied Soft Computing, vol. 25, no. 1, pp. 369-378, 2014.
[21] L. Chen, Y. Huang, H. Zheng, H. Hopman, and R. Negenborn, "Cooperative multi-vessel systems in urban waterway networks," IEEE Transactions on Intelligent Transportation Systems, 2019.
[22] H. Zheng, R. R. Negenborn, and G. Lodewijks, "Fast ADMM for Distributed Model Predictive Control of Cooperative Waterborne AGVs," IEEE Transactions on Control Systems Technology, vol. 25, no. 4, pp. 1406-1413, 2017.
[23] F. Goerlandt, J. Montewka, V. Kuzmin, and P. Kujala, "A risk-informed ship collision alert system: Framework and application," Safety Science, vol. 77, no. 1, pp. 182-204, 2015.
[24] B. Ożoga and J. Montewka, "Towards a decision support system for maritime navigation on heavily trafficked basins," Ocean Engineering, vol. 159, no. 1, pp. 88-97, 2018.
[25] W. Zhang, F. Goerlandt, J. Montewka, and P. Kujala, "A method for detecting possible near miss ship collisions from AIS data," Ocean Engineering, vol. 107, no. 1, pp. 60-69, 2015.
[26] R. Szlapczynski and J. Szlapczynska, "Review of ship safety domains: Models and applications," Ocean Engineering, vol. 145, no. 1, pp. 277-289, 2017.
[27] Z. Pietrzykowski, "Ship's Fuzzy domain – a criterion for navigational safety in narrow fairways," Journal of Navigation, vol. 61, no. 3, pp. 499-514, 2008.
[28] B. C. Shah et al., "Resolution-adaptive risk-aware trajectory planning for surface vehicles operating in congested civilian traffic," Autonomous Robots, vol. 40, no. 7, pp. 1139-1163, 2016.
[29] Y. Huang, L. Chen, and P. H. A. J. M. van Gelder, "Generalized velocity obstacle algorithm for preventing ship collisions at sea," Ocean Engineering, vol. 173, no. 1, pp. 142-156, 2019.
[30] R. Szlapczynski, P. Krata, and J. Szlapczynska, "Ship domain applied to determining distances for collision avoidance manoeuvres in give-way situations," Ocean Engineering, vol. 165, no. 1, pp. 43-54, 2018.
[31] Y. Huang, L. Chen, P. Chen, R. R. Negenborn, and P. H. A. J. M. van Gelder, "Ship collision avoidance methods: State-of-the-art," Safety Science, vol. 121, no. 1, pp. 451-473, 2020.
[32] C. Tam and R. Bucknall, "Cooperative path planning algorithm for marine surface vessels," Ocean Engineering, vol. 57, no. 1, pp. 25-33, 2013.
[33] H. Lyu and Y. Yin, "COLREGS-constrained real-time path planning for autonomous ships using modified artificial potential fields," Journal of Navigation, vol. 72, no. 3, pp. 588-608, 2019.
[34] R. A. Soltan, H. Ashrafiuon, and K. R. Muske, "ODE-based obstacle avoidance and trajectory planning for unmanned surface vessels," Robotica, vol. 29, no. 5, pp. 691-703, 2011.
[35] R. Szlapczynski and P. Krata, "Determining and visualizing safe motion parameters of a ship navigating in severe weather conditions," Ocean Engineering, vol. 158, no. 1, pp. 263-274, 2018.
[36] X. Sun, G. Wang, Y. Fan, D. Mu, and B. Qiu, "Collision avoidance of podded propulsion unmanned surface vehicle with COLREGs compliance and Its modeling and identification," IEEE Access, vol. 6, no. 1, pp. 55473-55491, 2018.
[37] J.-y. Zhuang, L. Zhang, S.-q. Zhao, J. Cao, B. Wang, and H.-b. Sun, "Radar-based collision avoidance for unmanned surface vehicles," China Ocean Engineering, vol. 30, no. 6, pp. 867-883, 2016.
[38] L. Chen, H. Hopman, and R. R. Negenborn, "Distributed model predictive control for vessel train formations of cooperative multi-vessel systems," Transportation Research Part C: Emerging Technologies, vol. 92, no. 1, pp. 101-118, 2018.
[39] M. Abdelaal, M. Fränzle, and A. Hahn, "Nonlinear model predictive control for trajectory tracking and collision avoidance of underactuated vessels with disturbances," Ocean Engineering, vol. 160, no. 1, pp. 168-180, 2018.
[40] Y.-T. Kang, W.-J. Chen, D.-Q. Zhu, J.-H. Wang, and Q.-M. Xie, "Collision avoidance path planning for ships by particle swarm optimization," Journal of Marine Science and Technology, vol. 26, no. 6, pp. 777-786, 2018.
[41] R. Szlapczynski, "Evolutionary sets of safe ship trajectories: a new approach to collision avoidance," Journal of Navigation, vol. 64, no. 1, pp. 169-181, 2011.
[42] M.-C. Tsou, "Multi-target collision avoidance route planning under an ECDIS framework," Ocean Engineering, vol. 121, no. 1, pp. 268-278, 2016.
[43] Y. Liu, W. Liu, R. Song, and R. Bucknall, "Predictive navigation of unmanned surface vehicles in a dynamic maritime environment when using the fast marching method," International Journal of Adaptive Control and Signal Processing, vol. 31, no. 4, pp. 464-488, 2017.
[44] A. L. Song, B. Y. Su, C. Z. Dong, D. W. Shen, E. Z. Xiang, and F. P. Mao, "A two-level dynamic obstacle avoidance algorithm for unmanned surface vehicles," Ocean Engineering, vol. 170, no. 1, pp. 351-360, 2018.
[45] "Convention on the international regulations for preventing collisions at sea, 1972 (COLREGs)," International Maritime Organization (IMO), 1972.
[46] L. Zhao and M.-I. Roh, "COLREGs-compliant multiship collision avoidance based on deep reinforcement learning," Ocean Engineering, vol. 191, no. 1, p. 106436, 2019.
[47] S. Centre, "Col regs – rule 19 conduct of vessels in restricted visibility," The Seamanship Centre, 2019.
[48] T. I. Fossen, "Marine control systems–guidance. navigation, and control of ships, rigs and underwater vehicles," Marine Cybernetics, Trondheim, Norway, Org. Number NO 985 195 005 MVA, www. marinecybernetics. com, ISBN: 82 92356 00 2, 2002.
[49] Y.-Y. Chen, C.-Y. Lee, S.-H. Tseng, and W.-M. Hu, "Nonlinear optimal control law of autonomous unmanned surface vessels," Applied Sciences, vol. 10, no. 5, p. 1686, 2020.
[50] S. McKinley and M. Levine, "Cubic spline interpolation," College of the Redwoods, vol. 45, no. 1, pp. 1049-1060, 1998.
[51] H. Shi et al., "Oscillatory particle swarm optimizer," Applied Soft Computing, vol. 73, no. 1, pp. 316-327, 2018.
[52] T. I. Fossen and T. A. Johansen, "A survey of control allocation methods for ships and underwater vehicles," 2006 14th Mediterranean Conference on Control and Automation, vol. 1, no. 1, pp. 1-6, 2006.
[53] T. I. Fossen and S. I. Sagatun, "Adaptive control of nonlinear systems: A case study of underwater robotic systems," Journal of Robotic Systems, vol. 8, no. 3, pp. 393-412, 1991.
[54] T. I. Fossen, "Guidance and control of ocean vehicles," John Wiley and Sons, vol. 1, no. 1, pp. 168-171, 1994.