Simscape targets co-simulation where
programming and CAD intersect. This
multi-domain tool ties together the Sim-
Electronics, SimDriveLine, SimMechanics,
and SimHydraulics tools. Back in Figure
1, the Stewart platform simulation can
incorporate electrical, hydraulic, mechanical,
and signal flow support in addition to
software control of the system.
Also, Simscape is a declarative language
that defines implicit relationships between
components versus the explicit programming
specifications for languages like C
and C++, or even graphical dataflow languages
such as LabVIEW. Companies like
Instron have used SimScape to develop
and build a multi-axis test fixture to assist
in evaluating race-car designs (Fig. 4).
According to Andew Plummer, manager
of control and analysis, Instron was
able to perform simulations on the system
five times faster, allowing models to be
refined more quickly. As with most simulation
tools, they were able to detect and fix
problems in the physical and algorithmic
designs faster.
A MODEL OF INTERACTION
By reducing the amount of expertise
required for developing mechatronic
applications, developers can expend time
and effort on other areas where they do
have expertise. Likewise, having a model
environment permits a better exchange of
ideas and products.
For decades, customers and suppliers
have exchanged CAD drawings. The difference
these days is the detail within the
models being exchanged as objects within
a mechatronic application become more
advanced. What used to be just dimensions
is now something that can be used
within a simulation complete with programmable
feedback and even application
interfaces when a model includes
application code.
Such a level of sophistication lets customers
specify criteria in a fashion that
can be used within a simulation and utilized
by the development tools. With the
MathWorks’ Simulink Design Verifier,
assertion blocks are able to be included
within a model so the system can determine
whether an object’s use within a
system is correct. These may be simple
asserts such as “a voltage should not go
over 10 V,” or they can be quite complex
such as “event X must occur within 25
seconds of event Y.”
Incorporating this type of design information
in a model also lets vendors deliver
virtual models of products for customers
to develop and experiment with. In many
instances, the actual product will not be created until the customer provides final
specifications for the model.
Standards in this arena are rare given
the number of vendors involved with their
own development tools, but occasionally
you’ll find commonality. For instance,
several automobile powertrain vendors
provide their customers with compatible
product models that allow for testing
and experimentation within a simulated
environment.
MIX AND MATCH MODELING
This experimentation is crucial to the
design process, and it can occur in a mixed
environment where real and virtual objects
are combined. A real robotic arm may be
coupled with a virtual assembly line, for
example, if the current task is to determine
if the hand on the robotic arm can re-orient
an object. Or, maybe it involves stirring a
virtual pot of molten plastic.
The key is getting the virtual objects and
their control counterparts to interact with
the real objects with code that’s running on
remote devices. For users of LabVIEW, the
development environment readily handles
this common occurrence.
Mechatronic development tools continue
to improve their functionality and performance,
making small projects easy and
large projects possible. Increased use of
mixed simulation in the development process
allows simulation to be used throughout
the development cycle and into deployment
and on-site testing.