Page 283 - The Mechatronics Handbook

Simulation Levels
Tool Supported
Mathematica, all
Matlab
MEMCAD low
SPICE low to medium
APLAC low to medium
ANSYS, CFD low to medium
SUGAR, NODAS low to medium
MemsPro low to medium
VHDL-AMS medium to high
*Because MEMCAD incorporates process simulations, it supports both physical
and behavioral views. All other tools support the behavioral view.

FIGURE 13.8 Available MEMS simulation tools, by level and view.

clear what the optimum number of levels of abstraction for MEMS would be. In Fig. 13.8 we have
attempted to classify some of the tools from Section 13.4 in terms of their ability to support various
levels (since these are simulators, they all support the “behavioral” view. MEMCAD, which allows
fabrication process simulation, also supports the “physical” view). Note that VHDL-AMS is the
only tool, besides the general-purpose Mathematica and Matlab, that supports a high-level view
of MEMS.
• Are there well-developed models, mature tools, and integrated development systems which are
widely available? While such systems do not currently exist, it is predicted that some examples
should become available within the next ten years [57].

13.6 A “Recipe” for Successful MEMS Simulation

A useful set of guidelines for analog simulation can be found in [67]. From this we can construct a set
of guidelines for MEMS simulation.
1. Be sure you have access to the necessary domain-specific knowledge for all energy domains of
interest before undertaking the project.
2. Never use a simulator unless you know the range of answers beforehand.
3. Never simulate more of the system than is necessary.
4. Always use the simplest model that will do the job.
5. Use the simulator exactly as you would do the experiment.
6. Use a specified procedure for exploring the design space. In most cases this means that you should
change only one parameter at a time.
7. Understand the simulator you are using and all the options it makes available.
8. Use the correct multipliers for all quantities.
9. Use common sense.
10. Compare your results with experiments and make them available to the MEMS community.
11. Be sensitive to the possibility of microlevel phenomena, which may make your results invalid.
The last point is particularly important. Many phenomena, which can be ignored at larger feature sizes,
will need to be taken into account at the micro level. For example, at the micro scale, fluid flow can behave
in dramatically different ways [44]. Many other effects of scaling feature sizes down to the microlevel,
including an analysis of why horizontal cantilever beam actuators are “better” than vertical cantilever beam
actuators, are discussed in Chapter 9 of [68]. Chapters 4 and 5 of [68] also provide important information
for low-level modeling and simulation.

©2002 CRC Press LLC