International Journal of Control, Automation, and Systems (2014) 12(4):852-860 DOI 10.1007/s12555-013-0189-3 ISSN:1598-6446 eISSN:2005-4092 http://www.springer.com/12555 An Advanced Cargo Handling System Operating at Sea Eun Ho Kim, Yun Sub Jung, Yonggyun Yu, Sangwon Kwon, Hanjong Ju, Soohuyn Kim, Byung Man Kwak, In Gwun Jang*, and Kyung-Soo Kim* Abstract: Mobile Harbor (MH) was recently proposed by KAIST as a novel maritime cargo transfer system that can go out to a container ship anchored in deep water and handle containers at sea. Since the system operates in at-sea conditions with waves and wind, the MH crane should be designed to suppress the swing motion of a spreader and compensate the relative motion between the MH and a container ship. For that purpose, we devised a state-of-the-art crane system equipped with a dual stage trolley, tension controller, and intelligent spreader with 3 degrees of freedom. We also integrated a ro- bust sensing system to measure remote motions in harsh open-sea condition. With these advanced sys- tems, we achieved swing free, position, tilting, and heave control systems for precise and safe cargo transfer. Experimental results with a 1/20 scale MH crane show the feasibility of the proposed system for at-sea cargo transfer. Keywords: At-sea cargo transfer, crane system, mobile harbor, position control, swing free control, tilting control. 1. INTRODUCTION Container shipping plays an important role in world- wide trade, and the quantity of goods transported by con- tainer ship every year continuously increases. Recently, supersized container ships whose capacities are over 10,000 twenty-foot equivalent units (TEU), have been launched to meet the strong demand in maritime logistics. The advent of supersized container ships has induced the needs to enhance the capacity and capability of container ports because existing container ports have reached their limits. Moreover, the supersized container ships require the construction of deep-draft ports for access. To ad- dress such demand, a new maritime cargo transfer sys- tem concept, the so-called Mobile Harbor (MH), has been suggested (Fig. 1) [1-3]. Conceptually the MH can go out to a container ship anchored in deep water and directly handle containers at sea instead of in a harbor. If the MH loaded and unloaded containers in the open sea and transferred them through shallow waterway such as a canal, we could expect the following: - To replace and augment functions of existing con- tainer ports while minimizing problems related with port construction and expansion, and - To provide an environmentally benign cargo trans- port solution and reduce the burden of overland car- go transport. In 2009, the MH Project was started with the support of the Korean government to develop original core tech- © ICROS, KIEE and Springer 2014 __________ Manuscript received April 17, 2013; revised October 21, 2013 and January 26, 2014; accepted February 25, 2014. Recom- mended by Associate Editor Jangmyung Lee under the direction of Editor Hyouk Ryeol Choi. This work was supported by the Industrial Strategic Tech- nology Development Program (10036235, Development of the core technology of light weight crane for mobile harbor) funded by the Ministry of Knowledge Economy (MKE, Korea). Eun Ho Kim is with the Human and Culture Convergence Technology R&D Group, KITECH, University of Science and Technology(UST), 143, Hanggaul-ro, Sangrok-gu, Ansan-si, Gyeonggi-do 426-910, Korea (e-mail: kimeunho@kitech.re.kr). Yun Sub Jung is with Medical Imaging Lab, Multimedia Team, DMC R&D Center, Samsung Electronics, Suwon, Korea (e-mail: yunsub.jung@samsung.com). Yonggyun Yu is with the Korea Atomic Energy Research Institute, Daejeon, Korea (e-mail: ygyu@kaeri.re.kr). Sangwon Kwon is with the Korea Institute of Machinery and Materials, Daejeon, Korea (e-mail: sanwonkwon@kimm.re.kr). Hanjong Ju is with Microautomation, SmartCity Apts., 46-15 Expo street 123, Yuseong-gu, Daejeon 305-748, Korea (e-mail: codenameju@microautomation.co.kr). Soohyun Kim and Byung Man Kwak are with the Division of Mechanical Engineering, KAIST, Daejeon, Korea (e-mails: {soohyun, bmkwak}@kaist.ac.kr). In Gwun Jang is with The Cho Chun Shik Graduate School for Green Transportation, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea (e-mail: jangin0407@kaist.ac.kr). Kyung-Soo Kim is with the Division of Mechanical Engi- neering, School of Mechanical, Aerospace and Systems Engineer- ing, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea (e-mail: kyungsookim@kaist.ac.kr). * Corresponding authors. Fig. 1. The mobile harbor concept.