Specifications

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disadvantage is that the number of computations grows exponentially with the number of parameters. A
two-parameter problem with five values of each parameter leads to 5 x 5 = 25 analyses, which is usually no
problem to do, while a five parameter problem will lead to 5^5 = 3125 analyses, which obviously is a more
time-consuming undertaking, at least for larger models.
The AnyOptStudy performs a systematic search within a parameter space using optimization techniques of
solutions that fulfill certain criteria. For instance, you could ask the study to find the saddle position that
maximizes the metabolic efficiency of the bicycle while keeping the maximum muscle activity below a
certain upper limit. The advantage of this study is that it does not need to compute al combinations of the
parameters and therefore can handle spaces with multiple parameters within a reasonable time. The
disadvantage is that it does not provide the overview of the design space that you get from a parameter
study.
This tutorial devotes one lesson to each of the two study types:
1. Defining a parameter study
2. Optimization studies
Without further ado, let us get the parameter study defined in lesson 1
.
Defining a parameter study
A parameter study is a systematic way to vary a number of model parameters and have the system
automatically run one or several analyses for each combination of parameters.
For instance, you may want to know how the forces affecting a joint prosthesis depend on the implanted
position. Or you may be interested in finding the standing posture by which you can hold a heavy box as
easily as possible between your hands. Or how the position of a handle influences the muscular effort of
operating it.
Or you may be interested in knowing how the seat height and horizontal position influence the muscle effort
and metabolism of the rider. This is precisely what we shall do in this tutorial. To make life a bit easier for
you, we have prepared a bicycle model you can download and play around with. Please click here
to
download a zip file and unpack it to some pertinent place on your hard disk.
The bicycle model is pretty much the 2DBike that you may know from the model repository
. In fact, the
structure of the model is as in the repository, so we have maintained the traditional division between the
BRep directory containing the human body model and the ARep directory containing the bicycle. You will find
the main file, OptTutorial.main.any, in OptimBike\ARep\Aalborg\OptTutorial (Notice the file
OptTutorial.final.main.any in the same location; this is a file that contains most of the additions we make in
the lessons of this tutorial). Please open The AnyBody Modeling System and load the main file. Opening a
model view window should give you this picture: