V5 Kinematics is an extremely user friendly product and can be used by any CATIA novice, all that is

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V5 Kinematics for Everyone
V5 Kinematics is an extremely user friendly
product and can be used by any CATIA novice, all
that is required is a very basic understanding of
V5 assemblies. It is one of the funnest (is that
a real word), coolest and easy to use products
from Dassault. Besides all that, its also
incredibly useful. This article will cover the
basics of kinematics in a very simple and easy to
understand manner. Kinematics allows you to make
your assemblies move. Of course we engineers
like to use fancier names, like mechanism
simulation or product animation, but
kinematics is really just making parts move, or
is it? And what exactly does move mean?
Actually we do need to watch our terminology (my
fancy name for words) a little because there are
actually several closely related topics that are
often confused with kinematics.
What is Kinematics
Finite Element Analysis (FEA) of a part Put one
end of a stick into concrete and push on the
other end. The stick will bend (move) but this
is not kinematics.
Finite Element Analysis of assemblies Build a
house on concrete and then blow on it. The house
certainly is an assembly and it does bend a
little under the wind (in Kansas they bend more)
but this is not kinematics.
Dynamic Analysis Imagine a crane picking up a
big block. If the block is to heavy the crane
might tip over. The crane has moving parts, but
additionally the moving parts are subjected to
forces (gravity, the weight of the block, or even
the inertia of the crane itself as it moves).
This is like kinematics on steroids, but this is
not kinematics.
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Deformable Dynamic Analysis Imagine the same
crane again, lifting the same block, only this
time we let the crane parts bend. This is kind
of a combination of kinematics, FEA, and dynamic
analysis, but you guessed it, this is not
kinematics.
Kinematics The traditional view of kinematics
starts with an assembly of parts that are
connected together by a variety of movable
joints. One of the joints is moved causing the
assembly to move. We dont associate loads or
weights with the parts, we simply are moving the
assembly of parts through some range of motion.
This is what we do with CATIA V5 DMU Kinematics
and this is kinematics.
What are Degrees of Freedom (DOF)
A part floating in space can move in 6 possible
ways. It has 6 Degrees of Freedom (DOF) 3
translation and 3 rotation.
A joint allows movement in only specific ways.
Here a Hinge joint only allows movement in one
rotation.
Assemblies can have more than one DOF. They must
have at least 1 DOF.
0 DOF (not allowed)
1 DOF
2 DOF
Now that we have all that fuss out of the way
lets turn our attention to V5 kinematics.
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V5 Kinematics Intro
Here is the outline we will follow. Later we
will simplify this procedure list down to 4
steps.
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Step 0 Get Ready
First you must to have all your parts in an
assembly. Each part needs to be in a separate
model (of course this is the proper V5 procedure
anyway). The assembly may contain
sub-assemblies, but as a beginner we will start
first with just a simple assembly made up of
parts.
Also as a beginner you should delete any
constraints in your assembly. Some (but not all)
kinematic joints are based on assembly
constraints. You may use your assembly
constraints, but only if they are the proper kind
for the proper joint. Sound like a mess? Well
it can be. Just delete them and let V5 create
the proper ones as it needs them.
Notice this branch called applications, this is
where your kinematics will go. Kinematics is
just one of the many different kinds of V5
applications (like the Rendering product) that
can be stored with your assembly.
Go to the Start menu and select the DMU
Kinematics workbench
Step 1 Create a Mechanism
From the menu select Insert ? New
Mechanism This is the bucket where all your
kinematic stuff will be placed. You can actually
have more than one mechanism stored within an
assembly, but again as a beginner we will use
just one mechanism.
Actually I often skip Step 1. If you go straight
to Step 2 and try to define your Fixed part then
V5 will prompt you at that time to create a new
mechanism.
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Step 2 Fix (anchor) a Part
At least one part needs to be held still and not
allowed to move. For the Four Bar Assembly I
selected the Base as the part to remain fixed.
Insert ? Fixed Part
Step 3 Define Joints
V5 has a variety of joints you can select
from. Select the type of joint that is
appropriate. Then when the Joint Definition
Panel appears simply select the requested
elements. The Revolute Joint requires you
select 2 axis 2 planes
For our Four Bar Assembly we chose to use 4
Revolute Joints.
Insert ? New Joint ? Revolute
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Step 4 Commands
Commands are applied to joints. They are what
forces the motion. You must have a command for
every DOF of your mechanism. In the case of our
Four Bar Assembly our mechanism has 1 DOF,
therefore, we need to define one command.
To define a joint to command simply double click
the joint (on the part or in the specification
tree) and select the check box (in this case
Angle driven).
How will you know if you have created enough
commands? Easy V5 will tell you. When it tells
you, go to Step 5.
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Step 5 Simulate (make it move)

• Now you can get things moving.
• Select the Simulation Icon
• Select Mechanism.1
• Then OK on the Select panel

You may create several simulations in an assembly
but since we are beginners we will settle for
just one.
Move the slider to move the mechanism.
Step 6 Other Stuff (collision checking,..)
Thats enough for now. There are many, many more
features within the V5 Kinematics workbench but
this is enough to get you started. Some of these
features are also integrated with other
workbenches. For example collision checking is
included in several workbenches, such as V5 DMU
Navigator.
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Summary
Heres what we have covered up to this point.
I think we can simplify this list a little
Authors Brian C. Barsamian and Shawn Ehrstein
are well known as outstanding educators and for
their dynamic presentations at COE.
Brian C. BarsamianMSC Software bcbarsamian_at_yahoo.
com
Shawn Ehrstein WSU CADCAM Laboratory shawn_at_cadcaml
ab.org