本論文提出一種水下無人載具的編隊策略用以解決傳統載具獨立工作之不便，為達到穩定的編隊型態，本論文引入領跑-跟隨法，其為自由空間中所使用之編隊技術，此編隊策略為直覺式。當一載具在前方發出跟隨訊號，另一載具在後方接收前方載具發出的訊號，並以此訊號作為方向移動與姿態調整的基礎，進而實現領跑-跟隨法的編隊策略。本論文之編隊策略與互動系統則使用LED光源與CCD建構，為避免編隊移動期間因水下環境造成訊號中斷，而設計一搭載全向性光源之水下無人載具，此光源會向四面八方發出光波，使得載具於水下工作時皆不會斷訊。再採用光源追蹤與影像處理之方式作為領跑與跟隨載具之溝通橋梁，根據跟隨載具接收影像上的光源面積大小進行距離量化分析，再利用水下距離演算法則進行跟隨距離的預測，即可得出領跑載具與跟隨載具之間的距離(l)。再藉由載具之間的水平與垂直角度對應到光源面積中心位置則可得到兩載具之相對水平角度(θ)與相對垂直角度(α)。有了距離(l)與相對角度(θ,α)則可帶入領跑-跟隨編隊策略追蹤目標載具的位置。本論文為使編隊移動更加靈活，在論文中導入水下載具互動系統，此系統是以光與影像的方式進行建構，前方領跑載具利用串列非同步傳輸將指令以二進制方式透過光源發送，再經由後方跟隨載具的CCD攝像頭接收光源並進行數值的轉化，使其在6bit/s傳輸速度下誤碼率可以低於1%以下，再透過解析出的參數進行追蹤動作。本論文所開發之水下載具追隨系統能有效的跟蹤目標光源，在不同亮度情況下載具最終相對偏轉角度皆小於失聯角度15°，並且由5m開始追蹤皆能準確停止在距離領跑載具1.5m處，而根據此兩點證明此編隊策略可應用於水下無人載具的追蹤功能。

This paper proposes a formation strategy for underwater vehicles to address the inconvenience of independent vehicle operations. The paper introduces the lead-follow method, where one vehicle emits a follow signal in front, and another vehicle receives this signal from the front vehicle to use it as a basis for direction and posture adjustments, thus achieving the lead-follow formation strategy. Both the formation strategy and the interaction system in this paper utilize LED light sources and CCDs. To avoid signal interruptions caused by the underwater environment during formation movement, a underwater vehicle equipped with an omnidirectional light source is designed. This light source emits light waves in all directions, ensuring uninterrupted communication for the vehicles during underwater operations. In order to make the formation movement more flexible, an interaction system is introduced in the paper. The lead vehicle employs serial asynchronous transmission to send instructions in binary format through the light source. The follow vehicle's CCD camera receives the light source and converts the data, achieving an error rate below 1% at a transmission speed of 6 bits per second. The developed underwater vehicle tracking system in this paper effectively tracks the target light source. The relative deviation angle of the vehicle under different brightness conditions remains below 15° from the disconnection angle. The tracking accuracy starts from a distance of 5m and accurately stops at a distance of 1.5m from the lead vehicle. Based on these two points, it is demonstrated that this formation strategy can be applied to the tracking function of underwater vehicles.

[1] Zhaoquan Zeng, Shu Fu, Huihui Zhang, Yuhan Dong and Julian Cheng, "A survey of underwater optical wireless communications", IEEE Communications Surveys and Tutorials, Vol. 19, no. 1, pp. 204-238, 2017.
[2] D. Levaché, D. Dhont, P. Lattes, A. Vida, L. Beguery, V. Del Marro, F. Besson and V. Rochet, "Underwater gliders for oil and gas exploration." 29th International Meeting on Organic Geochemistry. Vol. 2019. no. 1. EAGE Publications BV, 2019.
[3] Truax, Barry. Acoustic communication. Greenwood Publishing Group, 2001.
[4] E. M. Sozer, M. Stojanovic and J. G. Proakis, "Underwater acoustic networks", IEEE Journal of Oceanic Engineering, Vol. 25, no. 1, pp. 72-83, 2000.
[5] D. Pompili and I. F. Akyildiz, “Overview of networking protocols for underwater wireless communications,” IEEE Communications magazine, vol. 47, no. 1, pp. 97–102, Jan. 2009.
[6] Arkin, Ronald C., "Behavior-based robotics" in , MIT Press, 1998.
[7] Touraj Soleymani and Fariborz Saghafi, "Behavior-based acceleration commanded formation flight control", ICCAS 2010. IEEE, pp. 1340-1345, Oct. 2010.
[8] Dongdong Xu, Xingnan Zhang, Zhangqing Zhu, Chunlin Chen and Pei Yang, "Behavior-based formation control of swarm robots", Mathematical Problems in Engineering, Vol. 2014, pp. 13, 2014.
[9] T. Balch and M. Hybinette, “Behavior-based coordination of large-scale robot formations,” Proceedings Fourth International Conference on MultiAgent Systems. IEEE, pp. 363–364, 2000.
[10] Wenfeng Li and Weiming Shen., “Swarm behavior control of mobile multi-robots with wireless sensor networks,”Journal of Network and Computer Applications, vol. 34, no. 4, pp. 1398–1407, 2011.
[11] Qingyang Chen, Yujie Wang, and Yafei Lu, ‘‘Formation control for UAVs based on the virtual structure idea and nonlinear guidance logic,’’ 2021 6th International Conference on Automation, Control and Robotics Engineering (CACRE). IEEE, pp. 135–139, Jul. 2021
[12] Yi Liu, Junyao Gao, Cunqiu Liu, Fangzhou Zhao and Jingchao Zhao, "Reconfigurable formation control of multi-agents using virtual linkage approach", Applied Sciences, Vol. 8, no. 7, pp. 1109, 2018.
[13] Xiaomei Liu, Shuzhi Sam Ge, and Cher-Hiang Goh, “Formation potential field for trajectory tracking control of multi-agents in constrained space,” International Journal of Control, vol. 90, no. 10, pp. 2137–2151, 2016
[14] Volkan Sezer and Metin Gokasan, “A novel obstacle avoidance algorithm:‘Follow the gap method”’ Robotics and Autonomous Systems, vol. 60, no. 9,pp. 1123–1134, 2012
[15] Zhenhua Pan, Chengxi Zhang, Yuanqing Xia, Hao Xiong and Xiaodong Shao, "An improved artificial potential field method for path planning and formation control of the multi-uav systems", IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 69, no. 3, pp. 1129-1133, 2022.
[16] Xiaolong Tong, Shanen Yu, Guangyu Liu, Xiaodie Niu, Cunjun Xia, Jianke Chen, Zhe Yang and Yingyi Sun, "A hybrid formation path planning based on A* and multi-target improved artificial potential field algorithm in the 2D random environments", Advanced Engineering Informatics, Vol. 54, pp. 101755, 2022.
[17] Xinwu Liang, Hesheng Wang, Yun-Hui Liu, Weidong Chen and Tao Liu, “Formation control of nonholonomic mobile robots without position and velocity measurements,” IEEE Transactions on Robotics, vol. 34, no. 2, pp. 434–446, Apr. 2018.
[18] Jie Lin, Zhiqiang Miao, Hang Zhong, Weixing Peng, Yaonan Wang and Rafael Fierro, "Adaptive Image-Based Leader-Follower Formation Control of Mobile Robots With Visibility Constraints", IEEE Transactions on Industrial Electronics, Vol. 68, No. 7, pp. 6010-6019, 2021.
[19] Kuang-Yow Lian, Wei-Hsiu Hsu and Tsung-Shiuan Tsai, "Leader-Follower Mobile Robots Control Based on Light Source Detection", IEEE Sensors Journal, Vol. 19, No. 23, pp. 11142-11150, 2019.
[20] M. Stojanovic and J. Preisig, "Underwater acoustic communication channels: Propagation models and statistical characterization", IEEE Communications Magazine, Vol. 47, No. 1, pp. 84-89, 2009.
[21] M. S. Gupta, "What is RF?", IEEE Microwave Magazine, Vol. 2, no. 4, pp. 12-16, 2001.
[22] B. Kelley and K. Naishadham, "RF multicarrier signaling and antenna systems for low SNR broadband underwater communications," 2013 IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications, pp. 169-171, 2013
[23] A. G. Bell, "On the production and reproduction of sound by light", American journal of science, vol. 3, pp. 305-324, Oct. 1880.
[24] D. Mackay, Perspective on conventional underwater cameras, Oceanographic Literature Review, vol. 43, no. 9, pp. 21, 1996.
[25] The Sonardyne Site. Sonardyne International Ltd. [Online]. Available: https://www.sonardyne.com/products/bluecomm-200-wireless-underwater-link/
[26] C. Gabriel, M. Khalighi, S. Bourennane, P. Léon and V. Rigaud, "Investigation of suitable modulation techniques for underwater wireless optical communication", 2012 International Workshop on Optical Wireless Communications (IWOW). IEEE, pp. 1-3, Oct. 2012.
[27] M. A. Teece, "An inexpensive remotely operated vehicle for underwater studies", Limnology and Oceanography-Methods, Vol. 7, pp. 206-215, 2009.
[28] Aguirre-Castro OA, Inzunza-González E, García-Guerrero EE, Tlelo-Cuautle E, López-Bonilla OR, Olguín-Tiznado JE, Cárdenas-Valdez J., "Design and Construction of an ROV for Underwater Exploration", Sensors, Vol. 19, no. 24, pp. 25, 2019.
[29] M. Carreras, J. D. Hernández, E. Vidal, N. Palomeras, D. Ribas and P. Ridao, "Sparus II AUV-A Hovering Vehicle for Seabed Inspection", IEEE Journal of Oceanic Engineering, Vol. 43, no. 2, pp. 344-355, 2018.
[30] Y. Yasuda, N. Kubota and Y. Toda, "Adaptive Formation Behaviors of Multi-robot for Cooperative Exploration", 2012 IEEE International Conference on Fuzzy Systems. IEEE, pp. 1-6, 2012
[31] E. Semsar-Kazerooni and K. Khorasani, "Optimal cooperation in a modified leader-follower team of agents with partial availability of leader command," 2007 IEEE International Conference on Systems, Man and Cybernetics, pp. 234-239, 2007
[32] C. B. Low, "A flexible virtual structure formation keeping control design for nonholonomic mobile robots with low-level control systems, with experiments," 2014 IEEE International Symposium on Intelligent Control (ISIC), pp. 1576-1582, 2014
[33] A. D. Dang and J. Horn, "Formation control of autonomous robots following desired formation during tracking a moving target," 2015 IEEE 2nd International Conference on Cybernetics (CYBCONF), pp. 160-165, 2015
[34] Yanlin Zhou, Fan Lu, George Pu, Xiyao Ma, Runhan Sun, Hsi-Yuan Chen and Xiaolin Li., "Adaptive Leader-Follower Formation Control and Obstacle Avoidance via Deep Reinforcement Learning," 2019 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pp. 4273-4280, 2019
[35] D. Anguita, D. Brizzolara, A. Ghio and G. Parodi, "Smart Plankton: a Nature Inspired Underwater Wireless Sensor Network", 2008 Fourth International Conference on Natural Computation. Vol. 7, pp. 701-705, 2008