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).

Research on shipbuilding production logistics system combining MRP-Ⅱ with JIT

Shipbuilding production management and logistics control are studied so as to find an advanced shipbuilding production logistics management style.The necessity and feasibility to integrate MRP-Ⅱ(manufacture resource planning)and JIT(just-in-time)are researched properly following the comparison of MRP-Ⅱ and JIT and the analysis of shipbuilding production characteristics.A shipbuilding logistics system combining MRP-Ⅱ with JIT is set up and discussed according to a master production schedule(MPS),MRP and workshop-floor production control.The system is able to simplify the shipbuilding production plan,balance the workshop production,stabilize the supply,and inspire positivity and creativity so as to raise the shipbuilding production management level.

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.

An Overview of Bangladeshi Shipbuilding in the Light of Competitive Parameters

Shipbuilding in Bangladesh has been considered as the most promising industry in the recent time and the country is dreaming to emerge as a middle income country within a short time by maintaining the upward trend of this sector. However, due to global nature and the long term sustainability of this shipbuilding industry, an investigation of competitiveness in terms of global standard is of prime importance. This paper focuses on studying some crucial competitive factors like labor skill, labor availability, labor man-hour, labor cost ＆ productivity for local shipbuilding in Bangladesh. The analysis also focuses on existing access to the resources like materials, knowledge and capital which are equally important factors for the expansion of shipbuilding. Comparison of these parameters with other nations have been made qualitatively and quantitatively to find the level of our shipbuilding. On the basis of existing condition and future vision, some recommendations have been made which might be useful for accelerating the development of this sector.

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.

Layout Design-Based Research on Optimization and Assessment Method for Shipbuilding Workshop

The research study proposes to examine a three-dimensional visualization program, emphasizing on improving genetic algorithms through the optimization of a layout design-based standard and discrete shipbuilding workshop. By utilizing a steel processing workshop as an example, the principle of minimum logistic costs will be implemented to obtain an ideological equipment layout, and a mathematical model. The objectiveness is to minimize the total necessary distance traveled between machines. An improved control operator is implemented to improve the iterative efficiency of the genetic algorithm, and yield relevant parameters. The Computer Aided Tri-Dimensional Interface Application （CATIA） software is applied to establish the manufacturing resource base and parametric model of the steel processing workshop. Based on the results of optimized planar logistics, a visual parametric model of the steel processing workshop is constructed, and qualitative and quantitative adjustments then are applied to the model. The method for evaluating the results of the layout is subsequently established through the utilization of AHP. In order to provide a mode of reference to the optimization and layout of the digitalized production workshop, the optimized discrete production workshop will possess a certain level of practical significance.

Shipbuilding Technologies in Song China

In the Song dynasty,when a high premium was placed on the development of foreign trade by sea,the undertakings of shipbuilding and navigation thrived to an unprecedented degree.According to archaeological discoveries,multiple important breakthroughs were attained in shipbuilding technology at that time.First,watertight bulkheads became structurally improved and technologically mature.Second,there were various ways to joint multiple planks and different parts of a keel,embodying highly refined woodworking craftsmanship.Thirdly,bilge keels were in use,as were axial rudders that could move up or down,wood-and-stone anchors,and iron anchors.These technologies endowed such ship forms as the Fujian ship(Fuchuan福船)with excellent capabilities,bringing Chinese shipbuilding technologies to a peak in the Song dynasty.

Economics and Management of Shipbuilding Clusters： Possibilities for Integrating Croatian Shipbuilding in the EU Shipbuilding Industry

If managed properly, the shipbuilding industry could have a high multiplication effect. This is why it is often considered as the key industry in economic development in many national economies, especially those in transition. The three major players in the global shipbuilding industry are South Korea, China and Japan. Europe is positioned forth, but its market share is decreasing rapidly. This is also the case with the Croatian shipbuilding industry. This paper aims to critique the level of adaptability of Croatian shipyards to the rapidly changing environment of global industry. It also relates the question of survival and sustainable development of Croatian shipbuilding and strategic positioning of European shipbuilders. The results of this research had shown that without clusterizing the shipbuilding industry at EU integration level, and not at national levels, Europe will soon loose the struggle for market position improvement or even maintenance to the far more organized Asian rivals. Findings regarding the Croatian shipbuilding industry indicate the absence of a viable strategy on the national level. Furthermore, the paper tries to prove that success will be based on the possibility and will of Croatian shipbuilders to form strong collaborations mad business networks with subcontractors and other institutions. This should not be limited only at national level, but should incorporate different kinds of EU shipbuilding consortiums and clusters as well as other forms of strategic alliances.

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.

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.

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).