Specifications

Try expanding the ArmStudy root. You will get a list of the study types that

the system can perform. "Study" is a common name for operations you can perform on a model. When you

click one of the studies, the buttons on the middle, lower part of the panel come to life. Try clicking the

KinematicAnalysis study. With the buttons, you can now execute various types of analysis. The panel

contains three buttons:

• Run. This button starts the highlighted study and runs it until the end, usually producing some sort

of motion in the model. When Run has been pushed, it changes name to Break. If you push it in this

state, it pauses the running operation. F5 is a shortcut to this function to Run and Break.

• Step. This button advances the operation one step. What a step is depends on the type of

operation, but it is typically a time step in a dynamic analysis. (F6 is the shortcut key for Stepping)

• Reset. This puts the operation back to its initial position. You must reset before you can start a new

analysis, if you have stopped it in the middle. (F4 is the shortcut for resetting operations)

All these functions are also available from the Main Frame toolbar and the menu Operation.

Do you have a Model View window open? This is the one where you can see the model graphically. If not,

open one with Window->New model view from the pull down menus at

the top of the screen. Now, try your luck with the KinematicAnalysis

study and the Run button. What should happen is that the model

starts to move as the system runs through 101 time steps of the

study.

Since we have no muscles so far, kinematic analysis is really all that

makes sense. A kinematic analysis is pure motion. The model moves,

and you can subsequently investigate positions, velocities, and

accelerations. But no force, power, energy or other such things are

computed. These properties are computed by the

InverseDynamicAnalysis, which is actually a superset of the

KinematicAnalysis.

Try the Reset button, and then the Step button. This should allow you

to single-step trough the time steps of the analysis. When you get

tired of that, hit the Run button, and the system completes the

remaining time steps.

The analysis has 101 time steps corresponding to a division of the

total analysis time into 100 equal pieces. The total time span

simulated in the analysis is 1 sec. These are default values because we

did not specify them when we defined the ArmModelStudy in the

AnyScript model. If you want more or less time steps or a longer or

shorter analysis interval, all you have to do is to set the corresponding

property in the ArmModelStudy definition. When you click "Run", all

the time steps are executed in sequence, and the mechanism

animates in the graphics window.

So far, the model is merely a two-bar mechanism moving at constant

joint angular velocities. There is not much biomechanics yet. However,

the system has actually computed information that might be

interesting to investigate. All the analysis results are available in the

ArmModelStudy branch of the tree view. You can expand the tree as