Multi-Objective Redundancy Optimization of Continuous-Point Robot Milling Path in Shipbuilding

The 6-DOF manipulator provides a new option for traditional shipbuilding for its advantages of vast working space,low power consumption,and excellent flexibility.However,the rotation of the end effector along the tool axis is functionally redundant when using a robotic arm for five-axis machining.In the process of ship construction,the performance of the parts’protective coating needs to bemachined tomeet the Performance Standard of Protective Coatings(PSPC).The arbitrary redundancy configuration in path planning will result in drastic fluctuations in the robot joint angle,greatly reducing machining quality and efficiency.There have been some studies on singleobjective optimization of redundant variables,However,the quality and efficiency of milling are not affected by a single factor,it is usually influenced by several factors,such as the manipulator stiffness,the joint motion smoothness,and the energy consumption.To solve this problem,this paper proposed a new path optimization method for the industrial robot when it is used for five-axis machining.The path smoothness performance index and the energy consumption index are established based on the joint acceleration and the joint velocity,respectively.The path planning issue is formulated as a constrained multi-objective optimization problem by taking into account the constraints of joint limits and singularity avoidance.Then,the path is split into multiple segments for optimization to avoid the slow convergence rate caused by the high dimension.An algorithm combining the non-dominated sorting genetic algorithm(NSGA-II)and the differential evolution(DE)algorithm is employed to solve the above optimization problem.The simulations validate the effectiveness of the algorithm,showing the improvement of smoothness and the reduction of energy consumption.

Shipbuilding—An Analysis from the Perspective of Enterprise Resources Planning System

Designed as a tool for business intelligence, resource planning is used to manage the essentials of a business by integrating processes into a single system. Enterprise Resource Planning (ERP) solutions ensure all the organizational, operational, and procedural structures interconnection, which can be both an advantage and a disadvantage, knowing that inefficiency within one structure will lead to inefficiency in others. The originality of the approach consists in the unitary analysis of all processes which shipbuilding involves (design;evaluation of ship construction possibilities;contracting of works;contracting of supply of materials and equipment;presentation of inspections for the completed works reception;delivery of the ship into operation). The systemic approach is a notable contribution by highlighting the input and output quantities for the analyzed processes. Also, where it was found relevant, the diagrams highlight the owners of the process and show the interconnectivity of the functional departments within a shipyard. Although it is obviously the expression of in-depth knowledge of the peculiarities of Romanian shipyards, the authors hope that the work can support any shipyard that may be interested in knowing these structures (as a logical scheme mandatory to design a custom ERP software system).

Foreign Investment & China's Shipbuilding Industry——Interview with General Manager Wang Rongsheng of China Shipbuilding Industry Corporation

"China’s shipbuilding industry has boomed in the last 15 years since the end of the 1970s and has drawn attention of international shipbuilding and shipping circles even though a gap still remained between China and advanced shipbuilding countries including Japan and South Korea. China ranks among advanced shipbuilding countries relying on its own investment and enterprise development. China has opened its shipbuilding industry to the outside world for wider cooperation and more foreign involvement."

APPROACH FOR MODULE PARTITION OF BLOCKS IN SHIPBUILDING

To manage the complexities of hull module partitions, a new approach to the partitions of hierarchical modules for shipbuilding is proposed. Based on the assembly and manufacture process, the approach determines the hierarchy and basis of the module partition first, and then according to the type of connection between the parts of the block module, the degree of membership for the rational connection is gained and the fuzzy relation matrix between different parts is then established. The fuzzy clustering technique is used to partition the modules, and then the method of fuzzy comprehensive assessment is used to choose a relative reasonable scheme. A case study has been conducted, which proves that the approach is feasible and applicable; Especially it obtains the sub-module partition, which sets up the shipbuilding process at a higher-level assembly and has offered effective tools for the modular ship design.

Ship Maintenance and Repair Services in the Tema Drydock and Shipbuilding Yard in Ghana: Some Challenges, Opportunities and Prospects

This article explored existing policies (if any) and current management structure which govern operations within the yard, examine some major challenges facing the ship maintenance and repair services in Tema Drydock and Shipbuilding Yard, Ghana, identified few drivers that impact positively on the ship repair market with particular reference to the Tema Shipyard. It concludes by proposing sustainable management and maintenance strategies for improved repair services of the yard as well as analyzing the findings obtained in the data presentation and discussion sections during the research project. The main finding is that the PSC Tema Shipyard’s ship maintenance and repair services are really overwhelmed with major challenges, representing 55% after summing up four (4) out of the seven (7) captured in the study and are threatening its sustainability, if not properly researched and addressed once and for all. As already stated, carefully analysed conclusions were drawn to effectively address these challenges, followed by suggestions for future research to forestall its cascading effects on the Ghanaian economy as a whole.

Progress of the Chinese shipbuilding industry and welding technology

The China state shipbuilding corporation (CSSC), a leading shipbuilding enterprise of the Chinese shipbuilding industry, has made rapid progress during recent years. The welding technology, considered as the crucial factor in the development of the industry, plays a significant role. This paper presents the growth of shipbuilding technology, the associated welding processes and the prospects for the shipbuilding industry.

Research on the Computer Supported Cooperative Shipbuilding System Based on PDM

Shipbuilding is becoming more complex and requires many different enterprises and plants to work cooperatively to strive for the maximum profit.Supported by the computer technology,information technology,and internet technology etc., CSCW (Computer Supported Cooperative Work) plays a very crucial role in the multi-team,multi-subject,multi-layer field. According to shipbuilding characters and market requirements,the computer supported cooperative shipbuilding technology is re- searched actually.Key technologies to realize it are analyzed,and construction of the computer supported cooperative manufactur- ing environment is deeply discussed.On the base of them,scheme of the computer supported cooperative shipbuilding system based on PDM (Product Data Management) is put forward,which is useful to improve and develop the shipbuilding industry.

Shanghai Shipbuilding Industrial Corporation

Well knows as "half of the shipbuilding industry" in China, Shanghai is a major shipbuilding base. The Shanghai Shipbuilding industrial Corporation (SSIC),as a large regional corporation affiliated to the China National Shipbuilding Industrial Corporation, is composed of more than 30 shipbuilding and ship equipment enterprises,and design and research institutes and specialized corporations, mainly distributed in Shanghai and in Jiangsu and Anhui provinces, including a number of famous shipbuilders with substantial strength and scale, such as the Jiangnan Shipbuilding Group Corporation, Hudong Shipbuilding Group, Shanghai Shipbuilding Works, and Zhonghua Shipbuilding Works. Since its founding in 1981, the SSIC has always persisted in the policy of

Sino-Japanese Shipbuilding Cooperation

JaPan, wellknown for its international shipbuilding industry has begun to order Chinese built ships. In December 1993, the China Shipbuilding Industry Corporation signed an order for five new ships for Japanese owners including 15,000-dwt two bulk carriers. At the same time, China took the lead in research for a high-tech

China's Competitive Shipbuilding Industry

Since the 1980s when China’s shipbuilding industry entered the international market, the Dalian Shipbuilding Yard with sophisticated technology has built 27 ships totalling 1.13 million tons for 10 countries and regions. The Dalian yard has mastered 428 regulations of 19 countries including Britain, the USA, Norway, Japan

China's Shipbuilding Competitiveness

At the end of the Eighth Five-Year Plan period,a gloriousnew page was added to the historyof Chinese shipbuilding:for thefirst time China exported two 10,000ton bulk cargo carriers to Japan,the leading shipbuilding nation inthe world,with their delivery andlaunch held at the TianjinShipbuilding Company.In 1995,the China Shipbuilding IndustryCorporation received new shiporders of over 2.4 million tons,With a value of US＄1.5 billion.Ofthem,the exported ships accountedfor 99 percent and orders fromdeveloped countries and regionsaccounted for 90 percent.Atpresent,the Corporation’saggregated shipbuilding output isover 1.7 million tons,twice as muchas that of the 1980s,and its placein the world’s shipbuilding outputhas risen from the 16th to the 4th.

Achievements and developing trend of welding technology in Chinese shipbuilding

China's shipbuilding welding industry has passed a history of 40 years,and the rapid progresses in high efficient and automatic welding technology taken place in the recent 10 years, have made significant contribution to the development of national shipbuilding industry as well as to the state key projects, which promotes the welding consumables and equipment industry in China.This article presents the new welding technologices used in Chinese shipbuilding industry,particularly in recent decade,including new welding consumables and equipment,and economical benfit, caused by these new technologies,and predicts foe welding technology developing trend for Chinese shipbuilding industry in authors'opinion.

China Shipbuilding Trading Company

The China Shipbuilding Trading Company, which took the lead in breaking into the world market in reform and opening, registered rapid progress in the past year. The company obtained orders totalling 900,000 tons, tripling those for 1992. While consolidating its foothold in the markets in Hongkong, the United States and Norway, it developed

Development of China's Shipbuilding Industry

1997 is the 20th anniversary of Deng Xiaoping’s issuing of instructions on ship exports and also the 15th anniversary of the founding of the China National Shi-building Industry Corporation (CNSIC).

To Create a Big andl Strong Shipbuilding of China

Reality:A Big Gap Exists with StrongShipbuilding Countries We cad clearly see,though greatachievements have been made.China’sshipbuilding industry still has a large gapwith the ship building powers like Japanand South Korea. The gap is not onlyreflected in"quantity"(refer to the per-centage of delivery tonnage in the

China's shipbuilding industry since 1999

1.The development of China’s shipbuilding industrySince 1999, with the increasing demand of the world ship market and the support of the government to the development of the shipbuilding industry and other favorable factors, China’s shipbuilding industry has made significant progress. With the coming forth of new enterprises such as Nantong COSCO KHI Ship Engineering Company Ltd. (NACKS) and Waigaoqiao Shipyard, and the completion of the big dock projects of Hugong-Zhonghuo and New

US sanctions on Iran-the impact on shipping and shipbuilding industry

Since the US has reimposed the second round of sanctions on Iran recently,what kind of impact do they have on shipping and shipbuilding industry?

Leap-forward Development for China's Shipbuilding

China shipbuilding industry has shown its strong development trend at the beginning of the new century. It has entered a new stage of rapid developmentChina shipbuilding industry has achieved continuous development in the past 20 years since the beginning of opening up and reforming. China

Simulating molten pool features of shipbuilding steel subjected to submerged arc welding

Submerged arc welding process has been simulated to investigate the molten pool features of EH36 shipbuilding steel.One case only involved the surface tension model,and another one involved both the surface tension model and the interface tension model.The role of interface tension during welding is revealed,and the evolution of molten pool morphology is understood by comparing the surface temperature distribution,surface tension and interface tension distribution,and the streamline of the molten pool for the two cases.When the interface tension model is disregarded,a flow conducive to the outward expansion is formed in the surface area of the molten pool,resulting in a small weld depth-to-width ratio.After applying the interface tension model,the expanding outward flow is restrained,which leads to a deep penetration morphology with a large weld depth-to-width ratio due to the inward flow governed by the Marangoni forces.The simulation results involving the interface tension model have been verified with satisfactory predictability.