Design and implementation of automobile assembly m

Design and implementation of automobile assembly manufacturing execution system based on RFID

RFID (radio frequency identification) is a non-contact automatic identification technology. It uses RF signal to realize contactless information transmission through spatial coupling (alternating magnetic field or electromagnetic field), and achieves the purpose of identification through the transmitted information. The identification work does not need manual intervention. It has the advantages of large data storage, readable and writable, non-contact, long identification distance It has the advantages of fast identification speed, good confidentiality, strong penetration, long service life, good environmental adaptability, and can identify multiple labels at the same time, and can work in various harsh environments

in discrete manufacturing, as the central place of product manufacturing and the starting and ending node of finished product logistics and supply logistics, the manufacturing capacity of the workshop and its internal logistics capacity play a decisive role in the production capacity of the enterprise. As the hub of undertaking ERP (enterprise resource system), coordinating SCM (Supply Chain Management) system and scheduling the underlying production control system, manufacturing execution system (MES) plays an important role in the workshop production process. The fierce market competition puts forward further requirements for the modern manufacturing industry, which is embodied in the following aspects: a small number of various production modes, continuously shortening the production cycle, and timely response to the changing needs of customers. All these require the modern manufacturing industry to have a higher degree of automation and informatization. It has become an urgent task to study and apply RFID technology, explore and restructure enterprise information flow, give greater play to the existing resource advantages of China's manufacturing industry, and promote the technological progress of enterprises and the upgrading of traditional manufacturing industry. One of the ways to promote the development of MES is to integrate RFID technology into the traditional manufacturing industry

1 system requirements analysis

as a typical case in discrete industrial production, automobile assembly production activities have the following characteristics: the production process is parallel and asynchronous, the equipment function redundancy is large, the control quantity is independent of each other, the production resource management is complex, the parts in the production process are in a discrete state, and the vehicle production and manufacturing is mainly realized through physical processing and assembly

combined with the specific situation of an automobile production enterprise in Anhui Province, this paper studies the application mode of RFID technology in automobile assembly line

at present, the enterprise mainly uses bar code technology in the automobile assembly production line. The station staff manually scans the VIN code of the body and the bar code of parts for vehicle tracking and assembly information collection. The whole collection process is relatively time-consuming. When the bar code is damaged, stained and unrecognizable, the employee needs to manually enter the vehicle VIN code or part code, which has a high error rate and takes a long time, so it is difficult to speed up the production pace. The visualization of the production site needs to be improved. It is necessary to provide real-time and accurate assembly guidance for workers to eliminate the phenomenon of missing and wrong assembly. The assembly of vehicles on the production line also needs to be monitored in real time. The feedback of material consumption information is not timely, which makes it difficult to realize the real-time pull of production materials, resulting in excessive inventory of production materials and affecting the capital flow. The lack of associated management of employees and their assembly parts makes it difficult to implement the quality problems caused by manual operation to people

RFID technology is not just a simple replacement of bar code technology. Its application in discrete manufacturing industry will change the production and operation mode of discrete manufacturing enterprises. Because RFID technology has many advantages mentioned above, it can replace bar code to identify and track vehicles on the automobile production line. There is no manual intervention in the whole process, which can greatly reduce the labor intensity and error rate of workers. Nowadays, RFID technology can be used to realize automatic, high-speed and effective recording, reduce the labor intensity of operators, and improve the off-line qualification rate of products

applying RFID technology to automobile manufacturing industry and integrating it into MES system can improve the management and control level of production process and effectively track, manage and control the resources required for production, including materials, equipment, manpower and so on; Combined with the upper management system, it can reasonably schedule and manage these resources, improve manufacturing competitiveness, improve production organization, shorten production cycle, reduce the quantity of WIP, improve product quality and reduce human resource consumption. It has important theoretical significance and application value for developing discrete manufacturing system mode and application solutions, improving the level of visual monitoring of manufacturing process and product quality tracking, promoting the formation of RFID technology application standards in manufacturing industry, and driving the industrialization of RFID technology in China

2 system objective

based on the above demand analysis, the following general objectives of the system are put forward: make full use of the technical advantages of RFID and combine the MES system in the general assembly workshop to solve the problems between the planning layer of the current ERP system and the process control layer of the on-site automation system in the workshop, between the internal logistics layer of LES (logistic execution system) workshop and the production control layer of MES system The fault problem of information and management between the vehicle quality traceability system and the original MES system, so as to realize the visual and digital management of manufacturing and quality. Specifically, it is divided into the following sub objectives:

(1) combine RFID technology with production line scheduling system to realize the intellectualization of production line scheduling on the basis of production line scheduling automation

(2) integrate RFID technology and into the assembly station of the production workshop, use RFID tags to identify parts for data collection, master the material consumption information of the production line at all times, and pull the supply logistics without delay, so as to further meet the needs of JIT supply mode; Record the installation of important components to provide detailed and reliable data support for the quality traceability system

(3) combine RFID technology with on-site visualization system to provide real-time and accurate assembly guidance to station workers

(4) combining RFID technology with workshop personnel management system and quality traceability system can not only realize the function of personnel management, but also record assembly operations and implement assembly to people

3 application scheme of RFID technology on automobile assembly line

the application scheme involves two different types of RFID Tags: high frequency (13.56MHz) and ultra-high frequency (915MHz). The personnel are equipped with high-frequency RFID tags, which store employee ID and basic information; A high-frequency RFID tag is placed in each part material box, and the part number is stored in the tag; An UHF RFID tag is placed on each vehicle, and the unique identification code (VIN code) of the vehicle is stored in the tag. The vehicle label adopts glue magnetic packaging, which is convenient to be adsorbed on the surface of the vehicle body

before the vehicle goes online, the staff will install the initialization label on the upper surface of the engine cover at the front of the vehicle body

employees of the production line need to swipe their cards on the high-frequency card reader on the station to complete the on-the-job certification, and the system records the on-the-job status information of employees in the current station

before the vehicle goes online, the staff scans the VIN bar code of the vehicle body, and the UHF reader writes the VIN code information into the vehicle RFID tag within the antenna field strength. The subsequent stations complete the vehicle monitoring and data acquisition of the production line by reading and writing the RFID tag of the vehicle body

in the assembly station, after the UHF reader reads the vehicle label, it will prompt the installation information of parts in the corresponding station. The staff installed the corresponding parts and brushed the high-frequency RFID tag in the material box of the corresponding parts on the high-frequency reader. The system obtains the component installation information and staff information of the corresponding vehicle for later quality tracking. The system returns the material consumption information to the LES system and refreshes the prompt of the installation information of the parts at the station until all the parts to be installed at the station are installed. In the supply process to the production line station, after the production logistics department delivers the parts to the station, the system updates the quantity information of the parts

at the offline station, the UHF reader reads the vehicle tag, the system checks the assembly information, and the staff takes off the RFID tag for recycling

4 automobile assembly manufacturing execution system based on RFID technology

4.1 system function module

the function module of automobile assembly manufacturing execution system based on RFID technology is mainly divided into four functional modules: workshop production management, production line visualization, RFID tag management and workshop personnel management, The specific functional structure is shown in Figure 1:

Figure 1 functional model diagram of automobile final assembly manufacturing execution system based on RFID technology

workshop personnel management: manage the basic information of workshop personnel, configure the job information of employees, and provide relevant basic data for personnel work records, vehicle parts data acquisition and other functions

production management of the final assembly workshop: at the planning level, obtain the coarse-grained production plan from the ERP system, decompose it into the daily production plan, and guide the workshop production. Guide and monitor every assembly step of the vehicle in the production process of the whole vehicle, so as to standardize the whole production process, including providing assembly operation guidance to the assembly workers, automating the collection of vehicle assembly and material consumption data, and providing assembly records accurate to the information of parts and assemblers. These products have excellent lightweight potential, member information and supplier information, Feed back the consumption data of station materials to MES system in real time

production line visualization: provide real-time feedback of production line and vehicle status information, which is helpful for managers to grasp the production situation in real time

RFID tag management: responsible for the distribution and management of personnel tags, the distribution and recycling of tags in the recycling of vehicle tags, and the asset management of vehicle tags

4.2 system architecture

this system uses the RFID software middleware deployed in the workshop server to uniformly manage the workshop reader and writer network, which is conducive to shielding the differences of RFID equipment and improving the stability and efficiency of RFID reader and writer network. Moreover, the RFID equipment does not rely on the station terminal, and there is no need for special configuration of the station terminal, which is convenient for deployment. The structure of the automobile assembly manufacturing execution system based on RFID technology is shown in Figure 2:

Figure 2 no trapezoidal lead screw. The structure of the automobile assembly manufacturing execution system based on RFID technology

4.3 system software architecture

this system adopts B/S architecture. Under the J2EE development environment, combined with the mainstream open source frameworks such as struts 2, hibernate, spring and DWR, it has good cross platform compatibility. The software architecture of the automobile assembly management system based on RFID technology is shown in Figure 3:

Figure 3 the software architecture of the automobile assembly management system based on RFID technology

struts framework is a framework based on MVC (model view has a decisive role in tension accuracy measurement controller) mode, which is mainly realized by JSP and Servlet Technology. The system uses struts framework to integrate servlets, JSPS, custom tags and information resources to complete the response of the system to the operation of the front page

the system uses hibernate as the Java persistence layer solution to establish object/relationship mapping and realize the transformation from relational data to object data

as a web framework that realizes Ajax interaction, DWR can expose any Java object on the server side as a remote object that can be accessed through JavaScript in the browser. The system uses DWR framework to realize forward and reverse Ajax functions, and push the data obtained by RFID processing module to the response business module in real time, so as to reduce browser redundant requests, reduce server pressure and improve system operation efficiency

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