• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1324-1327
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• 1996

This paper presents an open architecture controller (OAC) for machining systems and describes the OAC testbed at Seoul National University. Because our OAC is designed for fully open systems, it does not depend on any specific hardware or software components. This openness includes software reusability which enables integration of a wide range of monitoring and control features. In addition to openness, our OAC system provides guaranteed real-time performance, an important requirement for advanced manufacturing.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.136-143
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• 2005

Open architecture controller (OAC) is well known technology in factory automation. To better understand the requirements of OAC, authors have discussed the OAC related topics with a number of control experts who represents different segments of the machining industry. There is no common concept that is accepted or used, however, the common ideas for OAC is the control system that is hardware independent, interchangeable, and easily scalable. This paper presents summary of the understaning and requirements of OAC. Based on the requirements of OAC, authors developed the software based PC-CNC. The main focus of the PC-CNC was on the user customization capability and open interface between control networks in manufacturing system. This paper introduces the developed PC-CNC briefly. In addition to introduction of the PC-CNC, to fill the gap between end users and vendors of OAC, this paper presents two applications using OAC. One is a remote monitoring system. The OPC (Ole for Process Control) standard interface was used to monitor the status of open architecture CNC across network. The other is the remote production management module for machine tools using standard database interface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.121-124
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• 2003

The conventional CNC(Computerized Numerical Controller) of machine tool, which is dependent to CNC maker, was a closed architecture type. Therefore, it is impossible to implement a special user-define function to CNC. But recently, CNC is changed to OAC(Open Architecture Controller) type increasingly and the general function of CNC can be upgrade efficiently. This paper describes web service application for remote monitoring regarding the faults or machine tool with open architecture CNC. The major faults of CNC machine tool can be defined to the operational faults to be charged over 70%. Those faults are unpredictable because of being occurred without any warning. To generalize the fault diagnosis efficiently. two diagnosis models such as SF(Switching Function) and SSF(Step Switching Function) are proposed and the function of fault diagnosis is implemented to internal function of OAC. Also, to service remotely the faults of CNC machine tool. the suitable web environment is proposed and practical function is programmed to evaluate its operation on web.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.136-142
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• 2004

This paper deals with the design and implementation of an open architecture CNC system for Wire-EDM, with a consideration of the difference between Wire-EDM and NC cutting machines. Recent open architecture controller(OAC) related research results could be applied to directly access Wire-EDM systems at the CNC level. However, previous research about OAC is mostly aimed at NC cutting machines such as milling or lathes, and hence these results are inadequate to apply to Wire-EDM. To close the gap between previous general research on OAC and Wire-EDM specific needs, an open architecture NC model for Wire-EDM composed of a synchronization kernel and a NC functional module is proposed. Based on the control information flow and Wire-EDM specific machining process, the conceptual CNC model and the detailed implementation model for Wire-EDM is suggested.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.292-297
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• 2004

The conventional computerized numerical controller (CNC) of machine tools has been increasingly replaced by a PC-based open architecture CNC (OAC) which is independent of the CNC vendor. The OAC and machine tools with OAC led the convenient environment where it is possible to implement user-defined application programs efficiently within CNC. Tis paper proposes a method of operational fault cause diagnosis which is based on the status of programmable logic controller (PLC) in machine tools with OAC. The operational fault is defined as a disability state occurring during normal operation of machine tools. The faults are occupied by over 70% of all faults and are also unpredictable as most of them occur without any warning. Two diagnosis models, the switching function (SF) and the step switching function (SSF), are propose in order to diagnose the fault cause quickly and exactly. The cause of an occurring fault is logically diagnosed through a fault diagnosis system (FDS) using the diagnosis models. A suitable interface environment between CNC and develope application modules is constructed in order to implement the diagnostic functions in the CNC domain. The diagnosed results were displayed on a CNC monitor for machine operators and provided to a remote site through a web browser. The result of his research could be a model of the fault cause diagnosis and the remote monitoring for machine tools with OAC.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1732-1737
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• 2004

This paper proposes Internet-based checking technique for machine-tools with variant CNC (Computerized Numerical Controller). According to the architecture of CNC, CNC is classified into two types such as CAC (Closed Architecture Controller) which is conventional CNC, and OAC (Open Architecture Controller) which is a recently introduced PC-based controller. CAC has a closed architecture and it is dependent on CNC vender specification. Because of this, it has been very difficult for users to implement an application programs in CNC domain. Therefore, an additionally special module is required for Internet-based application such as remote checking. In this case, web I/O embedded module can be efficiently applied for Internet-based checking. The module is directly attached to TCP/IP network for communication. In order to obtain the monitoring data of CNC machines, the I/O signals of the module are assigned to PLC (Programmable Logic Controller) input and output (I/O) signals within CNC domain. On the other hand, OAC has a PC-based open architecture and an additional module is not necessary for the connection with external site. Because of this, a simple DAU is just used for signal sensing and data acquisition without additional communication modules. For Internet-based remote checking of machine-tools with OAC, a user-defined daemon and application programs are implemented as the form of internal function within the PC-based controller. Internet communication is performed between the daemon program in CNC domain and web script programs in external server. Checking points defined in this research are classified into two categories such as structured point and operational point. The formal includes the vibration of bearing, temperature of spindle unit and another periodical management. And the latter includes oil checking, clamp locking/unlocking and machining on/off status.

• Journal of Mechanical Science and Technology
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• v.19 no.8
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• pp.1597-1610
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• 2005

The conventional computerized numerical controller (CNC) of machine tools has been increasingly replaced by a PC-based open architecture CNC (OAC) that is independent of a CNC vendor. The OAC and machine tools with an OAC have led to a convenient environment in which user-defined applications can be efficiently implemented within a CNC. This paper proposes a method of diagnosing the cause of operational faults. The method is based on the status of a programmable logic controller in machine tools with an OAC. An operational fault is defined as a disability that occurs during the normal operation of machine tools. Operational faults constitute more than 70 percent of all faults and are also unpredictable because most of them occur without any warning. To quickly and correctly diagnose the cause of an operational fault, two diagnostic models are proposed: the switching function and the step switching function. The cause of the fault is logically diagnosed through a fault diagnosis system using diagnostic models. A suitable interface environment between a CNC and developed application modules is constructed to implement the diagnostic functions in the CNC domain. The results of the diagnosis were displayed on a CNC monitor for machine operators and transmitted to a remote site through a Web browser. The proposed diagnostic method and its results were useful to unskilled machine operators and reduced the machine downtime.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.34-40
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• 2000

최근 CNC에는 또 하나의 전기를 마련할 수 있는 여러 가지 새로운 이슈들이 등장하고 있다. 첫 번째 이슈는 고도로 발달해가고 있는 반도체 산업의 영항으로 CPU의 속도가 기하급수적으로 달라지고 있고 메모리 용량이 상상을 초월할 정도로 급속한 발전을 거듭하고 있다. 이런 환경 속에서 자연스럽게 CNC도 성능이 우수한 하드웨어와 그 성능에 어울리는 고급 소프트웨어 탑재가 요구된다. 두 번째 이슈는 기존의 공작기계에서 생각하지 못했던 개념의 변화이다.(중략)

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.143-151
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• 2004

This paper deals with the precision NURBS interpolator for wire-EDM. Previous research about OAC (Open Architecture Controller) is mostly aimed at NC cutting machines such as milling or lathes, and hence these results are inadequate to apply to wire-EDM. In contradiction to NC machines, wire-EDM operates relatively slow feed rates and based on a feedback control loop to the machining process. The 2-stage interpolation method which reflects wire-EDM specific characteristics was proposed. The constant interpolation error could be acquired through 1 st stage interpolation. Feed rate regulation was performed through 2nd stage interpolation. The suggested algorithm was implemented to test-bed PC-NC system. Computer simulations and the experimental machining were conducted.