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Abstract Based on the work breakdown structure theory, the lean shipbuilding method guided by intermediate products is proposed in this article. The hull segment task package is divided according to the content of the shipbuilding operation. Considering the constraints of resources and personnel at the production site, the scheduling strategy of the task package is formulated. Moreover, a virtual flow production system of the shipbuilding workshop is established. On this basis, a lean shipbuilding manufacturing execution system for small and medium-sized shipbuilding enterprises is developed to achieve lean production in a shipbuilding workshop. The application results indicate that implementation of the lean shipbuilding method and manufacturing execution system can significantly reduce the ship production cycle and the number of operators, as well as improve the production efficiency. Introduction In recent years, to resist strong international competition, manufacturers are under great pressure to develop products more efficiently and economically (Nam et al. 2016). The ship manufacturing industry, which faces fierce market competition, helps many nations’ economic systems (Rahman & Karim 2015). For example, the shipbuilding industry contributed over $37 billion of the Gross Domestic Product (GDP) to the U.S. economy in 2013 (MARAD 2015). Currently, China’s shipbuilding industry is in a downturn. If the shipbuilding enterprises want to survive and improve their competitiveness, they must reduce labor costs and shorten the production cycle. Lean production is a type of management philosophy born in Toyota Motors. One of the lean thinking goals is to eliminate waste, which can increase work satisfaction and turn waste into value. It should be emphasized that lean thinking must go beyond the company. In other words, lean thinking has to be employed from the product design to the set of activities delivered to the end customer (Barbosa 2014). Lean manufacturing technology focuses on eliminating all types of waste in the manufacturing process and reducing the lead time (Zhu et al. 2019).

With continuous improvements in the function and performance of ship equipment, mechanisms of failure have become more and more complicated. To avoid over-maintenance or under-maintenance in existing routine ship maintenance strategies, a ship-level method for repair decisions based on the preventive maintenance concept is proposed in this paper. First, the anticipated repair demand levels of key components are calculated using an improved failure mode and effects analysis (FMEA) method; second, a Weibull distribution model is established, and the parameters are estimated using the maximum likelihood estimation (MLE) to predict the characteristic life of the equipment; then, logical decision principles and rule-based reasoning (RBR) are used to determine the ship repair level and repair timing. Finally, the feasibility and application value of the proposed repair strategy were verified by case studies, and a ship-level system for repair decisions was established.

This paper studies the production process of a shipbuilding enterprise. The company suffers from long manufacturing cycle, low utilization rate of personnel and an unbalanced production line. To solve these problems, the lean shipbuilding mode, mainly divided into shipbuilding work breakdown, production plan and virtual flow operation in this paper, is put forward, which combines the lean production and modern information management technology with shipbuilding. Supported by the theory of work breakdown structure and task package scheduling, the shipbuilding task package is reasonably divided. The priority of task package manufacturing is determined by calculating the task package manufacturing sequence coefficient, and a reasonable number of operators is calculated to ensure the continuity of segmented manufacturing. After determining the manufacturing priority of the task pack and the number of allocable personnel, the corresponding work can be scheduled. Production planning drives all production activities of the shipbuilding enterprise, and just-in-time production is achieved through the reasonable arrangement of these production plans, thus reducing the waste of personnel and time. Then, the virtual flow operation is carried out, which can achieve high efficiency of flow production and high flexibility of fixed workstation production during the production process of large-scale and heavy-duty products. The virtual assembly production system of the workshop is established according to the characteristics of shipbuilding operation and the actual production situation. On this basis, a lean shipbuilding manufacturing execution system for small and medium-sized shipbuilding enterprises is developed to achieve lean production in a shipbuilding workshop. Through the implementation of the lean shipbuilding mode based on task package scheduling and its manufacturing execution system, compared with the original data, the ship production cycle is reduced to 76.7%, the number of workers is reduced by 16.7% and the production balance rate is up to 81%.

In order to prevent traffic accidents caused by driver misapplication on the accelerator as a brake in emergency braking, an intelligent remedy system for misapplication on the accelerator in emergency braking of automobiles is proposed. The signal detected by the gas pedal pressure sensor is used as the discriminant parameter. C51 single chip computer is chosen as the core controller. Three dimensional modeling software of SolidWorks is used to establish the brake self-locking device. An intelligent remedy system for misapplication on accelerator in emergency braking is designed. As the system determines that the driver misapplication on the accelerator pedal during emergency braking, the signal is transmitted to the start switch circuit by the single chip microcomputer. Then the brake self-locking device is started to make the auto brake in an emergency. It can improve the active safety of car driving.

Simultaneous localization and mapping (SLAM) constitutes the core challenge in autonomous navigation while avoiding obstacles for mobile robots. Traditional robots require close-range operators during mapping, and remote control remains difficult in a complex environment. Furthermore, the height of sensors limits the detection of small obstacles in 2D mapping. This paper presents a robot system that solves these problems. The system operates SLAM remotely, navigates narrow paths, and estimates the location of small obstacles beyond the detection range of 2D lidar. The experiments utilized the Robot Operating System and an open source GMapping software package. Lidar, a camera, and an inertial measurement sensor unit enabled the remote monitoring of the robot in real-time via Rivz, Rqt, and V-rep. Experiment results demonstrate the advantageous operability and reliability of the system.

This study proposes a genetic algorithm to solve the biobjective vehicle routing problem with time windows simultaneously considering total distance and distance balance of active vehicle fleet. A new complex chromosome is used to present the active vehicle route. Through tournament selection, one-point crossover, and migrating mutation operator, the solution of the problem is solved. In experiment on Solomon’s benchmark problems, considering the total distance and distance balance, the results are improved in all classes of problems. According to the experimental results, the suggested approach is sufficient and the average GA performance is good.

In this paper we briefly present the concepts of ontology and Web Service, analyze the advantages that introduce them into robot control system. This research constructs the ontologies related with the control parameters of machine manipulator, designs a realization model and the corresponding services composition framework for the semantic Web Service based on ontology. Experimental results show that the approach improves the versatility of the various robot control systems, realizes the asynchronous communication within the clients and Web Service composites, thus enhances the real-time implementation of remote industrial robot control system as well as displays the information validity.