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A CORBA-Based Manufacturing Environment |
A CORBA-based distributed object software system was developed for Sandia's Agile Manufacturing Testbed (SAMT) in the IMTL. This information architecture supports the goals of agile manufacturing: rapid response to changing requirements; small lot machining; reduction in both time and cost of the product realization process; and integration within a heterogeneous, wide-area networked enterprise. Features of the resulting software-controlled manufacturing environment are:
Each of the heterogeneous physical objects (lathe, milling machine, robot arm, etc.) has a corresponding software object that supports a common IDL interface called IDevice. This interface provides operations for material processing, material movement, status monitoring, and other administrative tasks. CORBA objects allow for the encapsulation of a machine tool, its controller, and the network interface to the controller.
Both manual and automated operations are supported by the software system. If an IDevice object receives a request for a non-automated operation, such as running a particular program, it uses an associated IConsole object to effect the operation by communications with a human machinist. A design goal of the IConsole object for a machine is to provide an information-intensive environment for the machinist, rather than just the transmittal of instructions to be carried out.
In addition to the flow of information into manufacturing devices (e.g., control and NC code), our software architecture supports the easy extraction of data (e.g., sensor data or inspection reports) back out of the machine and into the broader information processing environment.
The task sequencer object dynamically locates devices, accepts jobs, and dispatches tasks in the manufacturing cell. A job script captures setup operations, material movement, and processing. Though the task sequencer coordinates cell activities, many operations can be accomplished intelligently by the devices. For example, all material transfer is performed as peer-to-peer object interaction, independent of the supervisory control of the task sequencer.
Ongoing work involves integrating this Testbed management system with process planning, integrated design, and inventory control systems.
The CORBA IDL for our manufacturing software can be found here. The resulting HTML pages of the IDL have been generated using idldoc.
We are presenting this work at the 1997 Hawaii International Conference on Systems Sciences (HICSS-97).