Hello,

I could obtain the simulation of my multibody with kinematic closed chain (CKC).

However, it seems that from a specific time (around 12s) in my model I believe that I have some numerical instabilities. Indeed, I could compare my simulation results with another mulbody software. I obtain the same simulation until 12s and after in MapleSim, it appears many perturbations as you can see on the figures belows.

So, I think that I tune the numerical solver. This numerical solver must solve DAEs equations since my model contains 4 kinematic closed loops.

If i read correctly the help menu, there are the following methods to solve the DAEs :

- use specific DAE numerical solver (3 differents solvers are used : ck45 method, RKF45 method and Rosenbrock method

- use reformulation equations techniques (Baumgarte, Projection) which can be associated (I believe) with a classic solver like (RK4).

For the moment, I have obtained my results with the rosenbrock solver with error absolute : 1.0*10^(-4) and eror relative :error absolute : 1.0*10^(-4) 

Do you have some ideas or advices so as to find a better method to solve my multibody systems with kinematic closed loops ? This method should  prevent the creation of numerical instabilities.

Thanks a lot for your help

Hello,

I would like to apply a torque directly on a revolute joint. I use a torque modulated by a signal source which is modified chirp signal.

I have done like in the figure below :

After having added this torque, my model no longer runs. The error message is only "simulation interrupted".

Do I correctly plug the torque ? Should I plug the torque element more in the flange a or b of the considered revolute joint ?

Do I tick "use support flange" ? Anyway, with or without, my model crashes.

Thanks a lot for your help.

Hi,

I trying to simulate a force sensor on robot arm, but every time I try something, I get nothing from my sensor, can you help me?

Here it's my "design":

Also, if I add a rigid body I get this error:

Thanks!

Hi,

I am trying to plot only the real part of the values obtained from the MapleSim model.  Probably there is a Modelica function to get only the real part of the values, but I am unable to find it. Could you please have a look at the code and let me know what I should do to solve this problem?

Best

Onder

The code is: (I want to plot the real part of R2)

model IKTest

parameter Boolean switched = false;
parameter Modelica.SIunits.Length L1 = 0.100;
parameter Modelica.SIunits.Length L2 = 0.102;
parameter Modelica.SIunits.Length L3 = 0.5;
//parameter Real c; //Complex number
//parameter c;

Modelica.Blocks.Interfaces.RealInput u[3]
annotation (Placement(transformation(extent={{-140,-20},{-100,20}},rotation=0)));
Modelica.Blocks.Interfaces.RealOutput y[3]
annotation (Placement(transformation(extent={{90,-10},{110,10}},rotation=0)));

Real Tx = u[1];
Real Ty = u[2];
Real Tz = u[3];
Real R1 = y[1];
Real R2 = y[2];
Real R3 = y[3];

equation

R1=atan(Ty/Tz);
R2=(acos((L1^2+L2^2-(sqrt(Tx^2+Ty^2+Tz^2))^2)/(2*L1*L2)));

//2*Modelica.Math.asin(1.0)
//R3=R2.re;

annotation (uses(Modelica(version = "3.1")));
end IKTest;

Hello,

I have a little question about the display of the kinematic joints which are usually in red.

I didn't know why the kinematic joints have disappeared and I don't know how to display them again.

Do you have an idea about the button I have to use so as to display the kinematic joints.

Thanks for your help.

Hello,

I have a question concerning the initial conditions.

One interest of MapleSim is to enable to model a multibody systems with different kinds of coordinates : namely relative and absolute coordinates.

For a complex system, it seems to me that the determination of the initial position is not an easy task.

Consequently, I wonder if it is possible to determine the initial positions for the system in absolute coordinates thanks to the knowledge of the initials positions in relative coordinates.

In other words, I have already determined the initial positions of my system in relative coordinates but as I would like to simulate my system with absolute coordinates. I wonder if I can have a process to deduct the initial positions for the absolute coordinates for the initial positions in relative coordinates.

Thanks a lot for your ideas and help.

Hello,

In my model, it seems that I have parameters which are not evaluated.

Indeed, I'm not sure that the parameters defined with relations as you can see in the printscreen are evaluated.

One point which helps me to debug my model is to follow the evaluation of the construction of my model with the 3D visualization.

Questions :
1) How can I do to be sure that my parameters are evaluated ?

2) Is it possible to launch the update of the 3D visualization even if I still have some bugs in my model ?

Thank you for help.

Hello, 

During the simulation of my model, I received this bug:

"cannot resolve function `Main.'Typesetting:-mambiguous'`; there is no function `'Typesetting:-mambiguous'` visible in model `Main`"

Have you a idea of the problem ?

How can I localize my issue ? Is there some options to localize the issue with a debug mode ?

Thanks a lot for your help

Hello,

In a subsystem, i defined parameters like this in the "parameters" area :

In the "diagram" area, the parameters are not updated because i see this panel :

Do you know why the parameters are not updated (possibly only on visualization) ? And if yes, how i can do to visualize in this last panel the value of the parameters updated ?

Thanks a lot for your help

Hi,

I want to calculate a new position (X,Y,Z) for a cartesian model with 3 points (dX,dY,dZ) but  I got a problem, my point is a parameters, so I can't change it in the simulation in real time with a Input signal on the components. Does It exist a solution for convert a parameters to a variable to get a Input signal?

Exemple of my calcul:

eq:= [x(t)= dx+sin(dy/dz), y(t)=dy+20,z(t)=dz]

Thanks!

Hello,

In my model, in order to better follow a analytical study, i would like to make some calculations with my paramters.

For example, I have defined :

xa=1

ya=2

R=sqrt(xa²+ya²)

I would define R in the parameters area so as to use it for some definitions in the definition of body (i use especially maplesim for multibody systems.)

How is it possible to define parameters thanks to relations ?

Hello all,

When I try to do this example, in the multibody analysis, http://www.maplesoft.com/products/maplesim/ModelGallery/detail.aspx?id=137

Thats already written :

but when I enter theses formulas(mModel & MB), that write instead of the example:

"Analyzing system..."
"Performing constraint analysis..."
"The system has 2 degree(s) of freedom. It is modeled using 2

generalized coordinate(s) coupled by 0 algebraic constraint(s\

And I have no result if i do vPosCons := MB:-GetPosCons(); . What am I doing wrong?

Thank you

Hello,

I would like to open a modelica model with MapleSIM. When I do "import modelica", I received the error message : "import failed : no library found".

I believed the modelica library was already installed on maplesim but may be not. Do I need to install modelica library ? and if yes, how ?

More generally speaking, how can I do to open a modelica model on maplesim?

Thank you for your help.

I have some data for a model in MapleSim that I would like to use a time look up table with.  I've found that the two options for interpolation are linear and 1st derivative, but the data was intended to be interpretted as piecewise constant.  Is there any way to acheive this option in MapleSim?

Hi

I tried to import the modelica library Buildings1.6 from the modelica website and get always the error "Nothing found in the modelica library". 

Is it possible to import modelica libraries? 

Thank you very much