Software Structures for Computer-Integrated Manufacture

Summary

The availability and sophistication of today’s computerized shop floor equipment promotes the concept of computer-integrated manufacture (CIM) providing a production facility that allows a variety of products to be manufactured combined with an inherent ability to reconfigure rapidly when new products are introduced.^5,6

These flexible systems, eg flexible assembly and flexible manufacturing systems (FAS/FMS), require the integration of a multiplicity of programmable devices for their collective: programming, control, monitoring and information acquisition; such systems can include eg: robots and other work transport systems, manufacturing machinery as well as inspection and production monitoring equipment.

This integration is accomplished at various levels from the provision of a common communication facility to the implementation of applications architectures which encompasses areas such as: system real-time control/dynamic scheduling, system programming, off-line job development, etc.

This paper addresses the problem of providing the fast, efficient communication facility required at each device. Many current devices have some communication ability, but this ability is often only a proprietary solution to the above problem due to the lack of an ‘open’ communication standard. The following discussion establishes the software requirements of a configurable local area network/shop floor device interface computer and the enhancements to existing equipment that can be achieved.

Further discussion concentrates on the concept of applications architectures with particular interest in the areas of system programming and system real-time control and the utilization of distributed resources that may be made available via the network. Finally, a description of the FAS currently in operation in the Department of Engineering Production at Loughborough University of Technology (LUT) is included. This FAS can assemble a mix of printed circuit boards (PCB) and has been constructed to investigate various network and applications architectures. The areas of discussion covered in this paper relate closely to the ongoing work of the General Motors Manufacturing Automation Protocols (MAP) initiative,⁹ and while established MAP protocols have been incorporated where possible, it is hoped that the work at LUT will provide a useful contribution to this international project.