Demands for increased control capabilities require next generation manufacturing machines to comprise intelligent building elements, physically located at the point where the control functionality is required. Networks of modular intelligent controllers are increasingly designed into manufacturing machines and usable standards are slowly emerging. To implement a control system using off-the-shelf intelligent devices from multi-vendor sources requires a number of well defined activities, including (a) the specification and selection of interoperable control system components, (b) device independent application programming and (c) device configuration, management, monitoring and control. This paper briefly discusses the support for the above machine lifecycle activities through the development of an integrated computing environment populated with an extendable software toolset. The toolset supports machine builder activities such as initial control logic specification, logic analysis, machine modeling, mechanical verification, application programming, automatic code generation, simulation/test, version control, distributed run-time support and documentation. The environment itself consists of system management tools and a distributed object-oriented database which provides storage for the outputs from machine lifecycle activities and specific target control solutions.
An open, reconfigurable and modular process monitoring and CNC operating system has been developed. The process monitoring system runs on a dedicated DSP board with analog input and output channels. New process control and signal processing algorithms can be rapidly applied by sequential execution of script commands provided in a library. The CNC operating system is a combination of an open real-time, preemptive DSP operating system and a Windows NT application, which are fully integrated with each other. It supports multiple DSP boards and multiple host computers for distributed operation. The system's transparent communication protocol allows connection between software modules on the same or different DSP boards and host computers. The connections can be set up at runtime via a scripting language. THe operating system allows modular integration of new functions developed in C language, and can be reconfigured to control robots, machine tools or processes, using simple script commands. The system can be used as an open architecture, modular operating system for the progressive development of real time signal processing, motion and process control applications running in WINDOWS NT and DSP environments.
This paper details the design evolution of an open architecture controller by presenting case studies of how the needs and requirements of end user, application/sensor developer and system integrator influenced the design methodology of the MOSAIC research platform, the first open architecture control supporting advanced capabilities. Degrees of openness such as Pseudo-Open, Piece-Wise- Commercial and Device-Independent are defined and explained in relation to various implementations of that research platform. The integration of sensors and adaptive control algorithms are used to illustrate how the services offered by the various design approaches impact the scope of the control's capabilities. The concepts of Machining Mode, Primitives, Functions and Operations are presented as a framework in which advanced machining capabilities can be categorized and used to ascertain the ease in which they may be integrated on various control architectures. New applications of technology and research results are also discussed offering a glimpse at the possibilities available on the open architecture.
Software development time, cost, and ease of (re)use are now among the major issues in development of advanced machines, whether for machine tools, automation systems, or process systems. Two keys to reducing development time are powerful, user-friendly development tools and software architectures that provide clean, well-documented interfaces to the various real-time functions that such machines require. Examples of essential functions are signal conditioning, servo-control, trajectory generation, calibration/registration, coordination of a synchronous events, task sequencing, communication with external systems, and user interfaces. There are a number of existing standards that can help with software development, such as the IEEE POSIX standards for operating systems and real time services; software tools to compliment these standards are beginning to see use. This paper will detail some of the existing standards, some new tools, and development activities relevant to advanced, 'smart' machines.
As part of its manufacturing initiative, TEAM is actively involved in open architecture controller activities. WIthin the TEAM community of members, TEAM is developing an open architecture controller requirements document and an open architecture controller application programming interface document. In addition, TEAM is also evaluating early open architecture controllers in a shop floor environment.
General Motors Powertrain Group (GMPTG) has been the leader in implementing open, modular architecture controller (OMAC) technologies in its manufacturing applications since 1986. The interest in OMAC has been greatly expanded for the past two years because of the advancement of personal computer technologies and the publishing of the OMAC whitepaper by the US automotive companies stating the requirements of OMAC technologies in automotive applications. The purpose of this paper is to describe the current OMAC projects and the future direction of implementation at GMPTG. An overview of the OMAC project and the definition of the OMAC concept are described first. The rationale of pursuing open technologies is explained from the perspective of GMPTG in lieu of its agile manufacturing strategy. Examples of existing PC-based control applications are listed to demonstrate the extensive commitment to PC-based technologies that has already been put in place. A migration plan form PC-based to OMAC-based systems with the thorough approach of validation are presented next to convey the direction that GMPTG is taking in implementing OMAC technologies. Leveraged technology development projects are described to illustrate the philosophy and approaches toward the development of OMAC technologies at GMPTG. Finally, certain implementation issues are discussed to emphasize efforts that are still required to have successful implementations of OMAC systems.
Machine-tool controllers are traditionally proprietary in design. Therefore, it is difficult to integrate third party hardware or software to enhance the functionality of either the machine tool or its controller. An open-architecture, PC-based controller merges as a good alternative. The Automated Production Technology Division at the National Institute of Standards and Technology, in collaboration with the US Navy, implemented an open-architecture, PC-based controller. This paper describes the design, implementation, and integration of this controller into a vertical machining center on the Portsmouth Naval Shipyard shop floor.
The shift to open-architecture machine tool computer numerical controls is providing new opportunities for metal working oriented manufacturers to streamline the entire 'art to part' process. Production cycle times, accuracy, consistency, predictability and process reliability are just some of the factors that can be improved, leading to better manufactured product at lower costs. Open architecture controllers are allowing manufacturers to apply general purpose software and hardware tools increase where previous approaches relied on proprietary and unique hardware and software. This includes DNC, SCADA, CAD, and CAM, where the increasing use of general purpose components is leading to lower cost system that are also more reliable and robust than the past proprietary approaches. In addition, a number of new opportunities exist, which in the past were likely impractical due to cost or performance constraints.
Proc. SPIE 2912, Implementation of hexapod functionality by open architecture development tools within the object-oriented C++ Siemens real-time CNC system, 0000 (20 January 1997); doi: 10.1117/12.263361
In today's marketplace, product quality and price have become requirements for entry and are no longer sufficient to differentiate one's product and gain a competitive advantage. A key to competition in the future will be a company's ability to respond quickly to a rapidly-changing global marketplace. Developers of manufacturing equipment must play a role in the reduction of the product development cycle time by increasing the flexibility of their equipment and decreasing its cost and time to market. This paper will discuss the implementation of an open-architecture machine controller on a flip-chip placement machine and how this implementation supports the goals of reduced development time and increased equipment flexibility. The following subjects are discussed: 1) Issues related to the selection of a standard operating system, including real-time performance, preemptive multi-tasking, multi-threaded applications, and development tools. 2) The use of a common API for motion, and I/O. 3) Use of a rapid application development and object-oriented programming techniques on the machine controller to shorten development time and support code reuse. 4) Specific hardware and software issues related to the implementation of the flip chip controller. This includes hardware and software implementation details, controller performance, and human interface issues.
A plug-and-play open architecture language environment for integration of mechatronic systems for agile manufacturing will be presented in this paper. This new language environment is designed to be computer platform independent, mechatronic device independent, and mechatronic system independent. The language environment is a salient extension and enhancement of Unix/Windows/C computing environment, popularly used by engineers and scientists all over the world. The language environment for real-time operation of mechatronic systems is a superset of interpretive C programming language implemented as a shell. We have designed and implemented this interpretive language environment with security provisions for cross-platform network computing. The mechatronic systems under this new integration paradigm, therefore, can be remotely operated thousands of miles away from the physical site across the network. An experimental rapid prototype system has been developed to verify our principles and algorithms on open architecture integration of mechatronic system. Hardware from different vendors can be easily plugged into the prototype system and the user can readily play it without changing application programs written in the superset of C. The new integration language environment is available for downloading on the WWW at the URL address.
Semiconductor fabrication requires an increasingly expensive and integrated set of tightly controlled processes, driving the need for a fabrication facility with fully computerized, networked processing equipment. We describe an integrated, open system architecture enabling distributed experimentation and process control for plasma etching. The system was developed at MIT's Microsystems Technology Laboratories and employs in-situ CCD interferometry based analysis in the sensor-feedback control of an Applied Materials Precision 5000 Plasma Etcher (AME5000). Our system supports accelerated, advanced research involving feedback control algorithms, and includes a distributed interface that utilizes the internet to make these fabrication capabilities available to remote users. The system architecture is both distributed and modular: specific implementation of any one task does not restrict the implementation of another. The low level architectural components include a host controller that communicates with the AME5000 equipment via SECS-II, and a host controller for the acquisition and analysis of the CCD sensor images. A cell controller (CC) manages communications between these equipment and sensor controllers. The CC is also responsible for process control decisions; algorithmic controllers may be integrated locally or via remote communications. Finally, a system server images connections from internet/intranet (web) based clients and uses a direct link with the CC to access the system. Each component communicates via a predefined set of TCP/IP socket based messages. This flexible architecture makes integration easier and more robust, and enables separate software components to run on the same or different computers independent of hardware or software platform.
Open architecture controls provide operators much more flexibility and ease in making modifications at the control. Virtual CNC machining, or verification, at the control provides a layer of safety as well as added functionality. The operator can replicate the metal cutting process, without the attendant hazards to part or equipment, often in significantly less time than the actual cutting time. If the operator makes modifications, the resulting virtual part can be sent back in electronic form to ensure conformance to the design intent.
The internet, widely available throughout the world, can be used to control robots, machine tools, and other mechanisms. This paper will describe a low-cost virtual collaborative environment (VCE) which will connect users with distant equipment. The system is based on PC technology, and incorporates off-line-programming with on-line execution. A remote user programs the systems graphically and simulates the motions and actions of the mechanism until satisfied with the functionality of the program. The program is then transferred from the remote site to the local site where the real equipment exists. At the local site, the simulation is run again to check the program from a safety standpoint. Then, the local user runs the program on the real equipment. During execution, a camera in the real workspace provides an image back to the remote user through a teleconferencing system. The system costs approximately 12,500 dollars and represents a low-cost alternative to the Sandia National Laboratories VCE.
The National Institute of Standards and Technology (NIST) is participating in the Department of Energy Technologies Enabling Agile Manufacturing (TEAM) program to establish interface standards for machine tool, robot, and coordinate measuring machine controllers. At NIST, the focus is to validate potential application programming interfaces (APIs) that make it possible to exchange machine controller components with a minimal impact on the rest of the system. This validation is taking place in the enhanced machine controller (EMC) consortium and is in cooperation with users and vendors of motion control equipment. An area of interest is motion control, including closed-loop control of individual axes and coordinated path planning. Initial tests of the motion control APIs are complete. The APIs were implemented on two commercial motion control boards that run on two different machine tools. The results for a baseline set of APIs look promising, but several issues were raised. These include resolving differing approaches in how motions are programmed and defining a standard measurement of performance for motion control. This paper starts with a summary of the process used in developing a set of specifications for motion control interoperability. Next, the EMC architecture and its classification of motion control APIs into two classes, Servo Control and Trajectory Planning, are reviewed. Selected APIs are presented to explain the basic functionality and some of the major issues involved in porting the APIs to other motion controllers. The paper concludes with a summary of the main issues and ways to continue the standards process.
The intelligent inspection system is an advanced controller and analysis system for dimensional measuring machines dedicated to measuring surface of revolution mechanical parts. IIS was developed by the Lockheed Martin Energy Systems, Inc. Oak Ridge Y-12 plant because no commercial product was available to replace the obsolete computing systems on these important machines.
MOSAIC-PM is based on a workstation/VME bus/Real time UNIX/C-language architecture. It is being used on a regular basis for a wide variety of demonstrations in 'intelligent systems and advanced manufacturing.' These demonstrations have included a) feature based machining, b) rapid prototyping by machining, c) networked manufacturing and d) sensor based machining. The goals of the demonstrations in sensor based machining are to improve the precision of the components being machined: i.e. to improve the capability of a 'standard' machine tool structure and give it some of the characteristics of a 'precision' machine. One routine uses a Renishaw touch trigger probe to inspect partially machined components after 'roughing'; the data collected are then used to modify the tool paths during 'finishing' to provide more precision. A second routine relies on a dynamometer to maintain constant force during cutting. This demonstration aims to achieve maximum precision by cutting at a constant force to keep tool deflection at a known value. During the demonstration, the dynamometer results are used as the feedback signal in the reference control loop of machining.
With the advent of touch probe technology, it was discovered that current closed architecture controllers do not provide adequate resources to support the implementation of process data acquisition on the shop floor. At AlliedSignal, a process data acquisition systems has been developed for a flexible manufacturing system utilizing touch probe and customized software which allows fixture and cutting tool related information for an entire process to be captured and stored for off-line analysis. The implementation of this system, the difficulties and pitfalls, will be presented along with the functionality required for an open architecture controller to properly support process data acquisition.
The great diversity of the devices that need to be interconnected in the industrial environment creates the need for interoperability. Communication interoperability is dealt with by using the Manufacturing Message Specification ISO 9506 standard in the application layer of industrial networks, which provides an abstract representation of the external characteristics of real manufacturing devices. In addition to the communication interoperability, the need for device interoperability has led to the definition of the user layer: an eighth layer in the OSI-RM for fieldbuses. The ISA/IEC SP50 emerging standard on fieldbuses defines the characteristics of the user layer functionality and the required objects. This paper presents an integrated solution for problems associated with industrial communications and control being developed at the University of Patras, Greece. Specific object oriented tools are being developed for the user layer. The function block builder tool allows the definition and creation of function block objects according to the emerging fieldbus standard. The graphical editing tool provides an integrated environment for the creation of logical node objects by means of interconnecting function block objects. The above tools are part of an integrated environment consisting of the application layer and the network management software. Furthermore, the graphical editing tool provides the capability of run-time monitoring as well as of dynamic reconfiguration of the industrial application. FInally, the complete systems has been installed in industrial test-bed applications.
Machine diagnostics and process optimization requires efficient techniques for the real time collection and dissemination of information to enterprise personnel. Open data presentations are required for the diverse software packages used by enterprise personnel, from process modeling and statistical process control to financial and Management Information Systems (MIS) packages. Current systems that enable rapid data collection tend to be vendor specific, point to point applications that are difficult and expensive to update, extend and modify. An open architecture is required that is capable of providing low cost real time collection and dissemination of information to end user applications. The development of an open architecture within the object oriented paradigm to solve a process optimization problem within a packaging organization is described in this paper. The architecture encompasses both the high level data dissemination and low level data storage and communications. A robust communications link between the sensors/intelligent nodes positioned on shop floor machines and the archive/dissemination medium is provided by a fieldbus network. The fieldbus communications link is configurable to allow the periodic sampling/monitoring shop floor data, and high performance collection of data regarding specific processes or events. The data transmission techniques utilized allow the high performance collection of data without disrupting object technology infrastructure. The common object request broker architecture is utilized to provide truly distributed systems for the myriad of applications used by enterprise personnel.
The authors discuss their progress to date in the design of fully functional CNC system. THe major factor influencing the end cost, effectiveness, flexibility and extensibility of a control is the basic architecture. The architecture described uses a highly parallel, patented arrangement, with the process control activity being carried out over an alternate front plane communication system. Examples of the use of this systems in both force and error control are given, in addition a relatively new extension of the system which allows increased flexibility is also discussed. A discussion of the use of a range of standard boards in the building of commercial systems will be used to demonstrate the flexibility which such controls should present to both OEM's and end users. Some of the potential problems which may arise are also discussed. The issue of operating software is discussed in some detail. The authors have standardized on the FORTH language for all low level software. It is believed that many in the control community are unaware of the recent ANSI and open firmware initiatives and indeed the potential of FORTH like languages in open embedded systems. The use of the FORTH interpreter allows the addition and actioning of code while the control is operating, this greatly adds to the flexibility of integration and reconfiguration.