Page 17 - Modular design for machine tools

Terminology and Abbreviations xv

as a synergy for the modular principle of FTL and conventional machine
tool from both the hardware and the software.
Following Koren and Ulsoy, Metternich and Würsching proposed a con-
cept represented with the term platform. This concept is substantially new
and can be interpreted as a mix concept based on mono- and plural-layered
type in the modular design [4]. In 2004, furthermore, Abele and Wörn pro-
posed an idea by combining the platform concept with reconfigurability;
however, this idea can be regarded as a variant of the modular design of
hierarchical type for producing the different kinds, when changing the
viewpoint [5]. In due course, at burning issue is how to incorporate the
definition of the platform within the term modular design.
A basic necessity is thus to authentically define the modular design
with wider acceptance. Within a system configuration context, further-
more, the modular design has been and is being widely accepted in close
relation to the system flexibility. In retrospect, the TL was once classi-
fied into a kind of machine tool, and thus in this book, the modular
design in flexible manufacturing will quickly be shown in Figs. 1-6 and
1-9. In such cases, the author will use the key term flexibility, although
we have other key terms, e.g., versatility, expandability, agility, and
reconfigurability. In this case, the author asserts the following.
Flexibility is a definition of space domain, i.e., the flexibility of system
configuration including those provided by the NC technology, whereas
agility is the flexibility of space and time domains, i.e., time series-
like flexibility of system configuration. Thus, the agility is worth pro-
posing in the next phase of production systems.

Furthermore, we have employed the term holonic manufacturing system
since the mid-1980s. In short, holonic concept correctly means the fusion
effects in functionality and performance of the two entities into one
entity having those effects more than the two entities. Marshall and
Leaney [6] suggested that the concept of holon be credited to Koestler
in 1967, and they stated the definition of the holon as follows.
Holons are autonomous self-reliant units which have a degree of inde-
pendence and handle contingencies without asking higher authorities
for instructions; simultaneously, holons are subject to occasional con-
trol from higher authorities.
Importantly, the concept of holon can be considered available for the
manufacturing system; however, some machine tool manufacturers have
recently characterized their products from the commercial-based view-
point by the term holonic machine tool. This trend induces further
terminology confusion nowadays.