## issues with angular displacement in given inverse ...

Hi,

I was playing around with the example "Simple Inverse Kinematic Problem" and found somethings to be odd:

the angular motion seems to be calculated from between pi and negative pi and this has some effects when using position block to move a joint.

the original angular displacement is graph below

the angular displacement after ik calculations have been performed:

if you run the simulation it seems to copy and mirror the input pendulum, however if you disable one of the IK solutions you see that infact its motion isn't like the input.

this becomes more prevailant when you use a position block to force rotation on a joint instead of using the 'prescribed rotation' blocks that comes with the example.

My question then:
why does this happen?
how do I work around this?

the importance that the motion is follow precisely becomes more prevailent when we want to extract other values such as vel, accel, torque. they are incorrect and very jumpy. Also simply put the angular displacement is wrong, how do I fix it?

(side note: I'm thinking  it has to do with the way arctan is calculated in maple limits it to stay in range -pi to pi
"For real arguments x, y, the two-argument function arctan(y, x), computes the principal value of the argument of the complex number x+Iy, so −π < arctan(y,x) ≤ π." from https://www.maplesoft.com/support/help/Maple/view.aspx?path=invtrig)

pjf

## Invalid File Format...

Hi,

I am trying to download some MapleSim Robotic models from the Maplesoft website but I have 'Invalid File Format' error. Could you help please?

Best

Onder

## Wind Turbine Vibrations Model Queries...

Dear forum users/ admins, I have some questions regarding the wind turbine vibrations model based on the MapleSim gallery. I am a new user, went through some tutorials and am currently trying to understand how the system works.

I will try to deliver my questions based on the pictures shown below:

1. After running the model, 2 results were shown. One is "Latest Results" and the other is "zeta=0.01". Based on the images above, there is a comment that the result was dated Feb 14 2013. Is this the result on which the day the model was created? If it is, is it programmed to be in the result file everytime the simulation runs?

2. If I untick "zeta=0.01", a red graph appears, which says Latest Result. But the graphs are not labelled. How can I label this graph in MapleSim?

3. I would also like to ask, what type of vibrations are occuring in the model, and what does the Deflection-Time graph means. Why does the deflection occur highest at 120s and then drops? Is it because the tower becomes stabilized after a while?

4. I understand that the model is run by a signal and fed into a speed component. May I know what is the f(critical) is, and how it affects the system?

5. From the Ramp signal, there is a "height" value. The pre-set value is 10. After changing this value, to lets say 50, the maximum deflections occur at a an earlier time as shown in the figure below:

6. I would like to understand how does the ramp affect the maximum deflection time that occurs.

Thank you very much!

## How do I connect 3 arms to a single part with revo...

I have created a model for a robot in Solidworks and have imported it into Maplesim using the CAD toolbox. The problem I have is that the robot has 3 arms that are supposed to come together on a central piece pictured below in figure 1, but attempting to simulate the model with all arms connected with a revolute joint as in figure 2 yields an error that says "The system is underdetermined" the location of the error is main.

For the purposes of the image below I only connected one of the arms, this allows Maplesim to run the file successfully.

figure 1 showing the central piece that the 3 arms are supposed to connect to.

Figure 2 showing the problem revolute joints circled in black, the error at the bottom and the setting of the revolute joint on the right.

Essentially my question is how do I get the model to work? I apologise if this problem is not terribly well demonstrated, this is my first post onto this forum so I am not sure of all the standards.

Dear MapleSoft,

Would it be possible you once design a MapleSim webinar for users with more emphasis on Modelica (language, examples, etc.), on how to build more complex custom components, not just a simple DC motor? I think this would be very useful and could extend / enhance the use of MapleSime even more.

best regards

Andras

you write:

## Where is oscilloscope icon?...

where i can found oscilloscope icon for cisuit simulation?thanks

## Circuit problem...

why the current luca_amplificatore_retroazione.msimand voltage is egual to zero?

How I can simulate control speed of car with sensor of speed, noise, feedback on maplesim?thanks

## Extract Linear Graph...

Does any one know if you can extract the linear graph from a Maple Sim model?  And by linear graph I mean the alternative to a a bond graph, not a type of plot.

## How to build this custom component?...

I want to build a custom component by the material’s stress-strain curve ,for the component signal input is the x(t)(displacement-time curve), then I can simulate the material’s acceleration-time curve，the stress-strain equation , parameter and the custom component I built has been given in the picture，but the x(t) is same as the s[rel](t),so how to solve this problem? Thanks first.

## Storage of the results of simulations...

Hello,

I have many tests to conduct on a MapleSim model. At each test simulations, I would like to change slightly some parameters.

As I have many tests to do (with different parameters), I would like to use a script so as to do like this :

Parameters test1
Store results of test 1

And so on ...

How can I do this kind of script ?

Is it possible to store the 3D animation results ?

## Flexible Beam State Variables ...

I'm trying to run c code generated from a simple MapleSim example (Spin Up Beam). To makes things even simpler, I set the input real expression to just time, and changed the input function in my c code to:

static void inpfn(double T, double *U)
{
U[0] = T;
}

I set all the state variables to 0 for the initial conditions. I ran the code and my output doesn't resemble the MapleSim output at all, and I'm getting errors. So my question is about the state variables, which I initially set to 0:

* State variable(s):
* x[ 0] = `Main.SpinUpBeam.FB3.uf1`(t)
* x[ 1] = diff(`Main.SpinUpBeam.FB3.uf1`(t),t)
* x[ 2] = `Main.SpinUpBeam.FB3.uf2`(t)
* x[ 3] = diff(`Main.SpinUpBeam.FB3.uf2`(t),t)
* x[ 4] = `Main.SpinUpBeam.FB3.vf1`(t)
* x[ 5] = diff(`Main.SpinUpBeam.FB3.vf1`(t),t)
* x[ 6] = `Main.SpinUpBeam.FB3.vf2`(t)
* x[ 7] = diff(`Main.SpinUpBeam.FB3.vf2`(t),t)

What do these represent for this flexible beam (FB3)? I.e. what is uf1, uf2, vf1, vf2? Should they be set to 0, or no?

Thanks.

## Use a "sub"module of the module GetMultibody...

Hello,

Thanks to the function Exports, it is possible to see the differents functions and modules which are in a module.

For example, I find in the module GetMultibody a module called GetLGM which permits to conduct some linear graph analysis. I'm interested by this module.

However, to my knowledge, I didn't see any help on this module.

How can I do so as to understand the inputs to give to the functions of this module in order to use the functions of this module ? In other words, how it is possible to use functions from a module when you don't have any help at your disposal ?

Thanks a lot for your help.

## Scale factor for 3D visualization...

Hello,

I use for the 3D visualization the component CAD geometry with STL files.
My STL files are created from CATIA with parts mesured in mm.
In MapleSim, in order to keep mm, I have, of course, to set "mm" in the inspector tab of the components "CAD geometry".
But, I have also to put the scale factor to 0.001.
I don't understand why I should to set it to 0.001 because :
- the CADs from CATIA are in mm.
- and the option in the inspector tab of the components "CAD geometry" is also in mm.
Would you have some precisions about the scale factor for the "CAD geometry" element ?