requirements and has deployed the lexical ontology
into the GSPAS application. In the rest of the article
we will describe the structure and usage of the existing KL-ONE ontology, and then describe the conversion approach and the conversion process.
In this article, we refer to the GSPAS KL-ONE ontology as GSPAS KB or as GSPAS ontology or as KL-ONE
ontology, and refer to the reengineered GSPAS OWL
ontology as new ontology or as OWL ontology.
GSPAS and the KL-ONE Ontology
Ford’s DLMS was developed to standardize vehicle
assembly, improve efficiency, and reduce cost
throughout the entire manufacturing process planning system. DLMS was then integrated into Ford’s
Global Study Process Allocation System, which is currently used across all of Ford’s global vehicle assembly and powertrain plants.
Artificial intelligence in GSPAS is used for several
different purposes: ( 1) Validate the correctness of
process sheets that describe assembly operations. ( 2)
Develop a list of operator work instructions and associated MODAPTS (modular arrangement of predetermined time standards) codes (Sullivan, Carey, and
Farrell 2001) for each assembly operation in the
process sheet. ( 3) Check the process sheet for
ergonomic concerns. ( 4) Translate the process sheets
into the language used at a particular assembly plant.
Figure 1 shows the architecture of the GSPAS AI
application. Figure 2 shows a sample process sheet
with five build steps and two tool specifications; at
such granularity, thousands of process sheets are used
to document the build steps for a whole vehicle. The
core of the GSPAS AI application is an ontology that
contains relevant knowledge about Ford’s manufacturing processes including the labor requirements for
the assembly operations, part and tooling information, workplace ergonomic concerns, linguistic representation of Standard Language (Rychtyckyj 2006)
and other concepts. Figure 3 shows how this ontology is used to generate operator work instructions
and MODAPTS codes. Each build step in the process
sheet is parsed and transformed into a KL-ONE
description, which is then classified to find the
matching concepts in GSPAS KB. The matching concepts provide meaning to a build step and also supply the necessary work steps and MODAPTS codes.
The ontology was developed inhouse using the KL-ONE knowledge representation language and
includes a graphic user interface for ontology editing
as well as a classifier. The GSPAS ontology has been
updated frequently to keep in sync with all of the
changes that have occurred to Ford and the automobile industry in general. The automotive business has
evolved dramatically and Ford itself bought and then
sold off companies such as Jaguar, Land Rover, and
Volvo. The manufacturing process, technology, and
tooling have all changed dramatically over the last
few years, and all of these changes needed to be
reflected in the GSPAS ontology. Technology and
parts for new products like electric and hybrid-elec-tric vehicles, in-vehicle infotainment, and aluminum
bodies all became part of the Ford manufacturing
process and consequently needed to be added into
Standard Language and the GSPAS ontology. On the
other hand, different concepts in the ontology
became obsolete and were no longer needed.
Throughout the intervening years and all of the
changes, the KL-ONE ontology model and classifier
proved to be robust enough to support GSPAS and
Ford’s manufacturing plants.
Ford adapted the KL-ONE knowledge representation system during its initial development of DLMS.
There were no KL-ONE tools or editors available so
Ford built both a KL-ONE editor as well as the code
for classification and reasoning (Rychtyckyj 1994).
The knowledge base update module, an in-house
developed graphic user interface, allowed us to maintain the KL-ONE knowledge base and also performed
error checking as part of the update process.
Figure 1. GSPAS AI Application.
TOOLS . . .
Figure 2. Process Sheet.
TITLE: ASSEMBLE IMMERSION HEATER TO ENGINE
10 OBTAIN ENGINE BLOCK HEATER ASSEMBLY FROM STOCK
20 LOOSEN HEATER ASSEMBLY TURNSCREW USING POWER TOOL
30 APPLY GREASE TO RUBBER O-RING AND CORE OPENING
40 INSERT HEATER ASSEMBLY INTO RIGHT REAR CORE PLUG HOSE
50 ALIGN SCREW HEAD TO TOP OF HEATER
TOOL 20 1 P AAPTCA TSEQ RT ANGLE NUTRUNNER
TOOL 30 1 C COMM TSEQ GREASE BRUSH