Page 12 - Mechatronic Systems Modelling and Simulation with HDLs

1

Objective and Motivation

1.1 Introduction

The objective of this work was to support the design of mechatronic systems by the
use of simulations. This raises the question of what exactly is mechatronics. Current
definitions describe mechatronics as an interaction between electronics, mechanics
and information technology, see Isermann [164] or Wallaschek [421]. It makes no
difference here whether we are talking about macromechanics or micromechanics.
In the former case we speak of mechatronics, in the latter of micromechatronics or
microelectromechanical systems (MEMS). As was discovered during the course of
this project, although the dimensions of the mechanics in the systems under inves-
tigation may vary, the methods used for modelling and simulation are largely the
same, which makes the joint consideration of macromechanics and micromechanics
an obvious approach.
Why is the modelling and simulation of mechatronic systems difficult? First of
all, the field of mechatronics incorporates very different domains and similarly var-
ied methods of description. The field of electronics includes analogue and digital,
as well as continuous and event-oriented, processes. The same is true of mechan-
ics, although often for totally different reasons. In the field of mechanics, events
may, for example, be triggered by the transition from static to sliding friction. In
electronics, on the other hand, an event is brought about by the flicking of a switch,
triggering a connection to the entire digital world. In mechanics we also have to
deal with geometric aspects in three spatial dimensions. Furthermore, multibody
and continuum mechanics of different representational forms also have to be taken
into account. Finally, software can be considered as information in bistable cir-
cuits and thus classified as electronics. However, this is not sufficient to achieve
an efficient and transparent consideration, which means that we have to develop
our own models for the software.
The development of models is thus a difficult process at the best of times and
one which is prone to errors. However, a systematic verification and validation of
the model is not in sight. As in other fields of simulation, models containing errors
can produce arbitrary results. Recognising such errors is often not a simple matter.

Mechatronic Systems Georg Pelz
 2003 John Wiley & Sons, Ltd ISBN: 0-470-84979-7