Keywords

1 Introduction

In 2016, The General Office of the State Council issued the Guiding Opinions on Vigorously Developing prefabricated Buildings, which clearly put forward eight key tasks: improving the standard and specification system, innovating prefabricated building design, optimizing the production of parts, improving the assembly and construction level, promoting the complete renovation of buildings, promoting green building materials, implementing general contracting of projects, and ensuring the quality and safety of projects [1]. Obviously, optimizing production of prefabricated building parts is the key to project quality. At present, there are still a series of problems in the production of prefabricated buildings, such as extensive construction, unstable construction quality, large labor demand, and large resource consumption, which need to be solved [2], which cannot meet the requirements of sustainable development of building energy conservation and environmental protection, and directly affect the promotion and application of prefabricated building production.

In view of this, many scholars have carried out relevant research on the construction cycle of prefabricated buildings. Based on BIM technology, Lin Shuzhi and Wu Dajiang [3] studied key issues such as the production, construction, operation and maintenance stages of the integrated application of prefabricated buildings, emphasizing the importance of intelligent construction to the development of prefabricated buildings, but the degree of intelligent construction at the present stage is not high. Gao Xiaoming, Ding Xiaoxin [4] and others put forward the standard system, digital management system and classification and coding system for the production of prefabricated building parts, which provided a useful reference for the intelligent production of prefabricated building parts. Xiao Tianqi [5] analyzed the difficulties of collaborative management in the process of production and construction of prefabricated building parts, and proposed the overall collaborative model of production and construction of prefabricated building parts, providing reference suggestions for its collaborative management.

To sum up, Many scholars have mainly analyzed and studied the intelligent production process such as the integrated system of prefabricated building production, the production of parts and components, and the digital management system. However, research reports on how to realize the intelligent and intelligent construction of prefabricated building production under the intelligent background are still rare. The intelligent construction of prefabricated buildings can be understood as construction process integrating green and intelligent [6], but there are still technical problems such as complex fine management of prefabricated components and imperfect industrial chain system. Therefore, how to realize the intelligent production of prefabricated buildings is a hot topic in the research of prefabricated buildings. The author will use the industrial Internet of things, multi-source information fusion dynamic monitoring and other key technologies to build the whole process of intelligent production of prefabricated buildings, and give the virtual simulation of intelligent production of prestressed concrete components, and summarize some conclusions that have practical guidance for intelligent production of prefabricated buildings.

2 Analysis of the Status Quo and Application of Prefabricated Building Production

2.1 Background and Significance of Intelligent Production of Prefabricated Buildings

In the context of intelligent construction, the research on the production optimization of prefabricated components aims at the production of prefabricated buildings, improving resource utilization, shortening production time, improving production efficiency and reducing production costs. Its significance is as follows:

  • (1) Theoretical significance: To provide theoretical reference for the production optimization of prefabricated buildings. Through the systematic analysis of the production process and process characteristics of the parts, the advanced production optimization method of the manufacturing industry is applied to intelligent production.

  • (2) Practical significance: to improve the production efficiency and service level of prefabricated buildings. Intelligent production method can improve the construction efficiency of prefabricated buildings, effectively reduce the production cost, improve the service level, and increase the promotion and application of prefabricated buildings. Intelligent production can image display optimization results, with stronger practical operability.

2.2 Key Process Flow of Prefabricated Building Production

The production process of prefabricated buildings refers to that after the design stage, the production process can be divided into two stages: technical preparation stage and production stage, as follows:

  • (1) Preparation of raw materials: according to the prefabricated components to deepen the number of design drawings and orders required to prepare the pre- embedded reserved materials, rebar, fixed tooling and materials required for the configuration of concrete, etc.

  • (2) Mold manufacturing: the management personnel need to determine the maximum number of molds that can be used in the single secondary production of each type of prefabricated component, namely the number of molds, to clarify the type and number of molds to be processed.

  • (3) Production scheme: mainly composed of the layout and scheduling scheme of the production workshop of the prefabricated building.

3 Intelligent Production Design of Prefabricated Building Based on Digital Technology

With the rapid development of digitalization and intelligence, a relatively complete intelligent manufacturing system of industrial Internet of Things has been gradually formed, which runs through the whole process of design, production, logistics, sales and service in intelligent manufacturing, mainly including [7]:①Interconnection of production equipment, ②identification and positioning of items, ③automatic detection of energy consumption, ④equipment status monitoring, ⑤remote monitoring, ⑥accessory product traceability and, ⑦monitoring of factory production environment. It can be seen that the development of this intelligent system has brought new development and application prospects to the intelligent production of prefabricated buildings. Intelligence is the basis for the development of prefabricated buildings to intelligent buildings. Therefore, combined with the assembly building “standardization, information, integration” and many other building characteristics, based on the digital and intelligent technology design of the intelligent production of the assembly building, intelligent production platform can be built, which mainly consists of digital workshop and intelligent platform, as follows.

3.1 Industrial Internet of Things Technology Design for the Digital Workshop of Prefabricated Buildings

According to the process environment, the combination of wired LAN and wireless LAN forms the basic industrial networkr [8], which provides technical support for the operation of the intelligent production workshop of the prefabricated building.

The intelligent production principle of prefabricated buildings is the digitization of many key links in the production line of prefabricated buildings, such as①enterprise LAN construction,②production workshop industry interconnection network construction, ③ display final control terminal, ④industrial computer, ⑤enterprise database system construction, ⑥ data storage cluster and ⑦ information security assurance. Then complete the interconnection between the production resource elements of the prefabricated building, and then based on the network equipment and data security protection technology, gradually realize the intelligent production of the prefabricated building.

3.2 Construction of Intelligent Production Line Data Acquisition and Monitoring and Control Platform

Digital technology and intelligent technology is the effective guarantee of the assembly building production integration process, and gradually transform the traditional artificial into integrated, in order to achieve the final goal of the assembly building parts integrated production, the formation of intelligent production line total control system modeling, its composition mainly includes organization modeling, product modeling, process modeling and soon. In order to achieve this goal, the key technologies areas follows.

Design of Data Acquisition and Interworking Between Devices.

The star topology structure is adopted to realize the interconnection between data acquisition and equipment. The specific performance is: through data collection, all the equipment of the intelligent production line workshop of PC components in prefabricated buildings are connected to the industrial Internet, and the data interconnection between the devices is realized through the control system.

Design of Production Workshop Data Acquisition Technology.

The key of intelligent production workshop is to establish a communication and transmission network, which can complete the transmission and storage management of data in realtime, build the digital model of production workshop, complete the protocol of data communication, data compression transmission, data aggregation and data storage, etc.

Real-Time Operation Monitoring Multi-source Information Fusion Technology Design.

Through the prefabricated building prefabricated components production real-time operation monitoring multi-source information fusion technology, to achieve the information interaction between multiple devices, equipment operating status monitoring, remote command delivery, remote intelligent control of equipment, the specific situation is as follows:

  • (1) Production line site management system: In order to solve the problems of abnormal production, quality problems, abnormal shortage of materials, equipment failure and other problems in the intelligent production workshop, it is necessary to identify the above problems, alarm the sudden abnormal events.

  • (2) Quality control system: The design collects and associates quality data in real time, and can find potential quality risks and problems in time, so as to realize rework and repair, quality visualization, and whole-process traceability management of quality. After the occurrence of quality problems, the cause of the problem is found in time, and the basis for subsequent treatment is provided, the analysis data and reports are provided, the product pass rate is improved, and the problems in intelligent production are reduced.

  • (3) Equipment management system: The equipment management system needs to store and dynamically share the production number of intelligent workshop equipment, and provide technical support for the comprehensive analysis of the equipment. For example, the implementation of dynamic monitoring of the operating status of key equipment, when the equipment fails or is in a maintenance state, the way of warning color or pop-up window to remind the workshop management.

4 Virtual Simulation of Prefabricated Building Intelligent Production Workshop -- Taking PC Components as an Example

Fig. 1.
figure 1

Site for the production of PC components in prefabricated buildings

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4.1 PC Component Intelligent Production Model Establishment

According to the facilities and equipment of the actual production line (Fig. 1), the 3D Max software is used to extract the outline and surface structure information of the equipment from the pictures and video data, create a model with the same scale as the actual equipment, and extract the detailed equipment size and spatial position data to complete the intelligent production three-dimensional model of PC components.

4.2 Design and Optimization of Prefabricated Building Intelligent Production Line

In order to improve the intelligent degree of prefabricated building production, reduce production risk and improve the benefit of the production line. Intelligent production line to do the following optimization design: ①build the same system framework of intelligent environment, including three-dimensional system, virtual assembly software, finite element analysis software, kinematics, dynamics analysis software, control system simulation software, design optimization software; ②Based on the device of the digital virtual production line, the intelligent system is designed and optimized; ③Support virtual prototype co-simulation operation, to achieve the lack of interaction with the real robot function; ④the virtual production line should include the whole process of the production process, such as mold table cleaning, mold table drawing line, side mold installation, embedded parts installation, fabric, steel lifting, etc.; ⑤The scheme optimization after parameter adjustment of the virtual reality system can obtain the best scheduling of intelligent production, which meets the design requirements.

4.3 Case Analysis of Intelligent Production of PC Components Based on Simulation Platform

Based on the above optimization design, this section gives the process model of intelligent production of PC components. The model mainly includes: mold cleaner, marking machine, oil injection machine, mold table, walking guide wheel, friction driving wheel, shaking table, concrete distributor, pre-curing system, surface hair drawing machine, rolover machine and other processes, as shown in Fig. 2.

Fig. 2.
figure 2

Prefabricated building intelligent workshop production PC construction virtual simulation

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5 Conclusion and Prospect

The organic integration of digital, intelligent technology and prefabricated building production has been the general trend in prefabricated buildings and even the entire construction industry, which is irreplaceable, and also marks an intelligent production mode of prefabricated buildings. At present, the software, talents and related technologies in the intelligent production of prefabricated buildings are not mature enough. However, after a lot of theoretical practice, with the development of intelligent software and related technologies, and further increase the training of intelligent related talents, intelligent production will be one of the most important means for intelligent production and construction of assembled buildings. Specifically as follows:

  • (1) In the context of intelligent construction, through the industrial Internet of Things technology, digital technology and intelligent monitoring platform technology, the intelligent design of prefabricated building production is systematically completed, simplifying the complex features of “personnel, equipment, safety, materials and process” of prefabricated buildings, realizing the “visualization” production process to the maximum extent, and promoting the prefabricated building to be more intelligent and efficient.

  • (2) Monitoring multi-source information fusion technology is used to integrate the facilities, equipment, technical parameters and other resources of the production process of the prefabricated building to optimize the design of the intelligent production of the prefabricated building. At the same time, based on network topology technology, the fine management process of the production of the prefabricated building is improved, such as: Production line site management, quality management and equipment management, etc., promote the production process of prefabricated buildings to be more digital and intelligent.