NOVEL STRUCTURE FOR DISTRIBUTED NUMERICAL CONTROL

Because of an unexpected signal noise within the network or an unpredictedfault with personal computers (PCs), many problems emerge in the implementation of distributednumerical control (DNC) with PCs-based network. To solve the problems, an industrial solution ofinvolving the field-bus technology in DNC communicating area is provided. A kind of advancedField-bus, named controller area network (CAN), is originally developed to support cheap and rathersimple automotive applications. However, because of its good performance and low cost, it is alsobeing considered in automated-manufacturing and process control environments to interconnectintelligent devices, such as modem sensors and actuators. Recently it creates a new role for CANBusin DNC that brings new thinking to DNC. CAN is used as the network platform for connecting machinetools to share information with each other reliably. Additionally, thanks to also applying of'plug-in' technology and a special interface of hardware, this solution exhibits some highcompatibility with different pedigree numerical control (NC) systems, such as Fanuc, Siemens,Cincinnati and so on. In order to improve CANBus for DNC application, a communicating competitionmodel of the basic CAN protocol, called CC model, is then highlighted. This model is able to satisfythe requirements that different machine tools share the communicating bandwidth fairly when theyrun concurrently. Finally the novel view of the latest advancement in CANBus-based DNC incombination with the manufacturing paradigm is also presented.

Key technologies for the novel distributed numerical control integrated system

A novel distributed numerical control (DNC) integrated system based on plug-in software technology is proposed. It connects new or old numerical control (NC) machine tools which have inhomogeneous numerical control systems with CAD/CAM system by CANbus network. A DNC computer is able to control 15 sets of NC machine tools reliably at the same time. The novel DNC system increases the efficiency of machine tools and improve the production management level by realizing non-paper production, agile manufacturing, networked manufacturing and so on in the near future. Key technologies to construct the novel DNC integrated system include the integration of inhomogeneous numerical control systems, NC program restart, and algorithm for communication competition. Such system has demonstrated successful applications in some corporations that have acquired good economic benefits and social effects.

Design and Implementation of Distributed Numerical Control in Flexible Manufacturing System

To monitor, control and manage the work process of computer numerical control machine tools in a flexible manufacturing system (FMS) effectively, the distributed numerical coutrol (distributed-NC) software should be innovated with the characteristics of modularization and reconfiguration. In this paper, firstly, distributed-NC functions in the FMS environment are described. Then, we present a design and development method of the real time distributed-NC that is on the basis of the re-coufigurable software and hardware platform and with an object-oriented model concept. Finally, to verify the proposed method, the distributed-NC software has been implemented in VC++ 6.0 and has been tested in connection with the different physical flexible manufacturing shops.

Web-services-based Integration Design of PDM and DNC Systems

In a networked manufacturing environment, product data integration is the foundation of collaborative manufacturing among manufacturing enterprises. It is very important to build an effective integration mechanism for product data sharing of manufacturing enterprises in geographically dispersed, heterogeneous system platform. In order to integrate enterprise level product data management (PDM) system and shop floor level distributed numerical control (DNC) system, based on the description of Web services technology, a Web-services-based integration approach is presented for facilitating seamless sharing of product data between PDM and DNC systems in a networked manufacturing environment. In order to verify the validity of the proposed approach, an example-based integration development has been implemented with Java 2 Software Development Kit and Java Web Services Developer Pack in Windows 2000 Professional environment.