Perception Of Manufacturing Resources In Cloud-Manufacturing System

Yan Jiming, Guo Zhiping, Shi Rongbo AVIC Chengdu Aircraft Industrial (Group) Co. Ltd

Chengdu, Sichuan, China, 610092 E-mail: yan_jiming@foxmail.com

Abstract-This article describes the characteristics and definitions of cloud-manufacture and focus on the two properties of the manufacturing equipment resources in cloud manufacturing systems: Static and dynamic properties. Perception of the manufacturing equipment is essentially the acquisition of these two properties. propose the device identification methods, data collection methods and data transfer protocol. Based on these methods, we describe the development of device-aware system.

Keywords-Cloud-manufacture; Manufacturing Resource; Resource Perception; Processing equipment; Data collection; Data transfer

I. INTRODUCTION Based on the fact that China's manufacturing industry is

facing large-scale manufacturing duplication of resources, inefficient high power consumption, etc. the academician Li Bohu of Chinese Academy of Engineering, firstly proposed a new model- cloud-manufacture in 2009, which provide a new solution for the problem above. Literature[1] [2] describe the characteristics of cloud manufacture and give the definition of it: cloud-manufacture integrate of the existing manufacturing information technology, cloud computing, Internet of Things, Semantic Web, high-performance computing technology etc. according to the extension and change of the existing network of manufacturing and services, cloud-manufacture makes all kinds of manufacturing resources and manufacturing capabilities, virtualized and service. Meanwhile it focuses on the intelligent management and operation, intelligent, and win-win situation, pervasive and efficient sharing and collaborative. Through the network, it can provide readily available reliable, on-demand, secure, high-quality low-cost service to product’s life cycle: early stage of manufacture (such as feasibility studies, design, processing, marketing, etc.) medium-term of manufacture (such as the use, management, maintenance, etc.), and the end manufacturing stage (such as dismantling, scrapping, recycling, etc.). Schematic diagram shown in Figure 1[2].

In the Figure 1, There are three main user roles in Cloud manufacturing system: Resource providers, Manufacturing cloud operators and Resource users. Where the resources are the sum of the elements involved in the product life cycle, which is the basement of the system. It contains the Manufacturing Resource and Manufacturing abilities[2].

Manufacturing resources refers to the physical presence, with a resource in the form of static transmission medium, such as processing equipment, simulation software, models,

knowledge, data, documents, referring to objective existence of physical resources[2]. The literature[2] lists on this detailed classification shown in TABLE I:

TABLE I. RESOURCES CLASSIFICATION OF CLOUD MANUFACTURING SYSTEM

Manufacturing Resource

Soft resources

Software Knowledge

Human

Hard resources

Manufacturing equipment Computing resources Material

Other related resources Manufacturing

abilities Design abilities

Production abilities ...

For all resources, manufacturing equipment (such as various types of machine tools, testing equipment, etc.) is undoubtedly the most critical and basic resources, but also the most difficult resources to perceive. How to realize resource-aware manufacturing equipment is the key to cloud manufacturing system.

Figure 1 Cloud-manufacture Run Schematic Diagram[4] According to the definition and classification of

resources, manufacturing equipment resources have both static and dynamic properties. While the static property refers to the flag information of the device, such as name, function, and the use of static description. The dynamic

2012 International Conference on Computer Science and Service System

978-0-7695-4719-0/12 $26.00 © 2012 IEEE

DOI 10.1109/CSSS.2012.497

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property refers to the active state of the equipment during operation.

This paper focuses on sensing technology for manufacturing equipment in cloud manufacturing systems, including manufacturing equipment, real-time access to information, information package, information transmission technology, Which lies the foundation for the realization of intelligent identification and management of the manufacturing cloud of manufacturing resources.

II. MANUFACTURING EQUIPMENT SYSTEM DIAGRAM Including CNC machine tools, coordinate measuring

machine, such as various types of manufacturing equipment, manufacturing resources tend to be the terminal executor of cloud manufacturing systems. In the manufacturing process, the status of the device is subject to change, in order to reflect real-time device status, device-aware system has a more complex hierarchy than any other resource-aware systems. as shown in Figure 2.

Figure 2 hierarchy of device-aware system Diagram Because many devices are involved in manufacturing, we

must firstly solve the identification problem in device-aware system, which uniquely identifies the device. After uniquely identification, the information of equipment operation is transferred to the data center for packaging.

A The identification of manufacturing equipment resources In order to identify manufacturing equipment resources,

you must encode the information that can only characterize their characteristics. At the same time, build the device information database about the static properties of the resource and encoded device as a table. The coding can be based on the number of devices, type, model, many digital encoding, or is just a serial (number does not mean the other meanings). With equipment code , as long as the system gathers equipment code, you can query the device information database to the resource name, function and static property. it can also mark the appropriate equipment condition information.

B Information collection Manufacturing equipment operation information is

specifically listed below: 1) the machine POWER ON/OFF time 2) the name of the machining part

3) the name of the processing procedures 4) processing procedures starting 5) processing procedures to suspend 6) stop the processing procedures 7) the segment being processed 8) tool (tool number, tool length) 9) Spindle running information 10) the feedrate 11) the machine alarm Of all the information,1)is the device usage information,

2) is the name of the machined parts, 3) to 7) are the stages of part processing (process step), 8) to 11) are cutting tools and machine status information.

This information is a comprehensive description of the status of the device processing, Due to the real-time collection of this information, you can accurately meet the cloud manufacturing system during the operation of the underlying dynamic allocation of resources and on-demand requirements.

C Information Processing The operating information from equipment (multiple

devices), data collection need to be measured in milliseconds, in order not to miss any state. Therefore the amount of data collected is very large and especially in complex cases, such as equipment failure, making the acquisition doubled the usual amount. It will lead to the formation of the surge data stream. While the data transmitted on the Ethernet, will definitely lead to network congestion, seriously affecting the operation of other systems.Meanwhile, if the storage or processing is in a timely manner, it will result in data loss, which loses of the value of the analysis and application.

In addition, when the workshop network failure, the data collected will be unable to spread to the data server, resulting in information interrupt.

Under these conditions, Using data caching and interim approach, The collected real-time data be hierarchically bufferred,and be packaged to the chronological order number.and uploaded to the server in the network normal,then they are classified, packaged in the server,to achieve resource requirements of virtualization.

D Data Centre The data center located in the top level of the perceptual

system is a database server. The data collected, is uploaded to the server, where each packet of data will be classified by static and dynamic properties of each device package. In this way, processing equipment was fully virtualized.

III. MANUFACTURING EQUIPMENT AND KEY TECHNOLOGIES

Manufacturing equipment resources differ from other resources in the change of its state. How to get real-time access to device status and send out real-time transmission is the key technology of cloud manufacturing systems.

A The technology of real-time data collection CNC machine tools can generally be connected via RS-

232 serial port, the DNC interface, and the OPC (OLE for

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Process Control, OLE Process Control) interface and network interfaces to the outside world. For different CNC system, you can use the corresponding method for operating status information collection.

The following commonly used CNC system FANUC CNC system and Siemens CNC system are good examples of the machine real-time data collection technology.

The FANUC CNC system, through the macro way, inserts macros in the NC program output state information. Operation status information storing variable values of the CNC machine tool are outputted from the serial in real time. FANUC system operating state information variables

PART shown in TABLE II

TABLE II. FANUC SYSTEM OPERATING STATE INFORMATION VARIABLES PART

System variables Name Description

… ……Through the instruction of the machine serial output

variables: DPRNT .such as output the system variables “# 3008 " through the Windows output, the instruction is:

DPRNT [#3008]. In terms of Siemens CNC system, you can use the OPC-

based acquisition methods which is a set of technical specifications and industry standards using client / server mode.

The OPC server is the supply side of the data. it collects the data of field devices. OPC client applications communicate OPC server through the OPC standard interface, to obtain a variety of information of the OPC server.

Form the figure 3, OPC Server based on Industrial Ethernet uses Simatic NET with independent client.

The Simatic NET is a automation technology software

based on OPC to support multiple communication protocols. It is widely used in various types of distributed automation systems and communicate with the S7-300 PLC.

When the device's status changes, the corresponding input of the PLC interface changes, the OPC server will collect the signal change in the PLC module, OPC client programs read the data of the server changes via OPC standard interface ,analyze the received data and obtaine the status of the machine.

In addition, there is a common collection method by developing hardware circuit, it get the machine run state obtained through machine PLC I/O port interface.

B Real-time data transmission processing communication protocol

Real-time data transfer processes adopt three-layer transmission processing mode: machine collector-to-PC repeater – central control processor , the dump-and-forward repeater receive real-time data collected by the collector, and

finally sent it to analyzing processing, before it is written to the database.

Figure 3 Siemens data acquisition system chart

Figure 4 Real-time data processing flow chart In order to achieve the multi-layer service architecture

which is distributed open, complete and accurate communication between the upstream and downstream service, system needs to design a dedicated communication protocol to assemble the static attribute information of the corresponding equipment and the collected data, using the following format:

Command # device number # # data number ## password # # encrypted real-time information flow string

For example shown in TABLE III: The acquisition layer or more layers use this agreement

to the package the data and then do some transmission and exchange of information.

TABLE III. SPECIAL COMMUNICATION PROTOCOL(FOR EXAMPLE)

protocol Request format Returns format Transfer Real time

data

RTDATA## device number ## data number

##data##

null

Start file transfer

FILEDATA ## device number ## data

number ## data ##

FILEDATA ##FILEEND

… … …

IV. MANUFACTURING EQUIPMENT PERCEPTUAL SYSTEM IMPLEMENTATION

Based on these technological achievements, we develop a device-aware system, the system works is shown in Figure 5. The system is mainly used at some of the numerical control system, the use of appropriate collection techniques,

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development and CNC systems run in parallel data acquisition module, access to the machine the underlying data; machine data filtering module, through the filtering of the data obtained, we obtain able to characterize the machine run state, and processing the data. Figure 6 is the perception to a single device operation information.

Figure 5 Interface for Perception system of CNC machine tools

PC repeater using a windows service mode, through the sockets and the collector, the control processor, web data receiver connected communications, realize real-time data reception, dump, forwarding and sending.

Figure 6 A machine tool real-time operational status from device-aware system

Windows service model design, the use of the oracle of the multi-dimensional partition storage mode, to receive real-time data files from the repeater sent machining, analysis of storage after processing, to meet the requirements of resource virtualization.

Figure 7 Processing recording of single device

V. CONCLUSION Of all the variety of resources in cloud manufacturing

system , the most difficult one is to perceive the processing equipment. and the key lies in the dynamic properties of information processing equipment acquisition. This paper focuses on numerical control system in the domestic, centralize the collection of operating status information form processing equipment, as well as transmission and processing methods. Moreover we develop the perceptual system which has already been applied in AVIC Chengdu Aircraft Industrial (Group) Co. Ltd. Because of the versatility and practicality of these methods, they will not only facilitate the promotion applied to private and shared manufacturing cloud system but also be used in other digital manufacturing system.

ACKNOWLEDGEMENTS Supported by National Science and Technology major

projects in China (2010ZX04015-011).

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