This was done in OMEdit by setting specifying the Linearization time in the simulation flags settings at time 0.


I'm also trying this in OMNotebook, first loading the Modelica library, which should include the Modelica_Linear_Systems2 2.3.2 libraries. In OmNotebook,
When I use the set command to linearize: setCommandLineOptions({"+d=linearization"}), I get the following error message:

{false}
OMC-ERROR:
"Error: Unknown debug flag linearization."


I'm using the latest nightly build, downloaded today.

Not sure why it's not recognizing the d flag, this comes right out of the OMNotebook example: E411tanksystem.onb. Maybe I don't have things pointed
to the correct folders.

Any help would be welcome.



Thanks.

Hi,

I'm trying to linearize a fairly simple Modelica model using OpenModelica 1.9.1Beta4. The model contains a point mass whose motion is constrained through a prismatic constraint with a spring-damper connected to the prismatic joint. Upon model linearization (at t = 1sec.) the simulation returns 0 for all elements in the state-space matrices.

The output of the end of the OMEdit log is:

  parameter Integer n = 2; // states
  parameter Integer k = 0; // top-level inputs
  parameter Integer l = 0; // top-level outputs
  parameter Real x0[2] = {0,0};
  parameter Real u0[0] = {i for i in 1:0};
  parameter Real A[2,2] = [0,0;0,0];
  parameter Real B[2,0] = zeros(2,0);
  parameter Real C[0,2] = zeros(0,2);
  parameter Real D[0,0] = zeros(0,0);
  Real x[2](start=x0);
  input Real u[0];
  output Real y[0];

  Real x_Pprismatic1Ps = x[1];
  Real x_Pprismatic1Pv = x[2];
     
equation
  der(x) = A * x + B * u;
  y = C * x + D * u;
end linear_springmass1;

Any insight into this issue would be welcome. The model is attached.

Thanks.

Hi,

I am having problems getting the attached model to run. I'm trying to model a simple system consisting of two rigid body parts connected by a revolute joint. I'm trying to apply a periodic force (just a single component force in the x-direction of the b-frame) to the 2nd rigid body.

I get the following error message: "Too few equations, under-determined system. The model has 1529 equations and 1531 variables." I don't see what is wrong with this model, it should be a simple 1-DOF problem.

Can anybody offer any suggestions.

thanks.

Hi,

I'm having further problems getting a simple model to run correctly. I'm trying to duplicate a simple model shown in the Modelica User's guide: http://modelica.github.io/Modelica/help … orldForce. I've set all of the parameters just as the example shows. Upon trying to simulate I get 3 error messages: 1) "Type mismatch in binding k={-800,400,0}, expected subtype of Real(start=10), got type Integer [3]" 2) "Error occurred while flattening model wecpart" 3) same as 1) above. I've attached the model.

I thought we had to stipulate that the force has 3 components as indicated by the 3 component vector for k. Is this not correct? Not sure why I'm getting this error message when it's exactly the example given.

Any help would be most appreciated. Thankyou.

Thankyou. That solved the problem.

Hi - I'm trying to develop a simple model in OpenModelica. I'm trying to apply a constant force (using the const block with k = {1000.0,0.0,0.0}) to a World Force block. The a-frame of the World Force block is connected to the b-frame of a rigid body (using bodyshape block). Upon attempting to simulate, I get the error message: "Type mismatch in binding k = {1000.0, 0.0, 0.0}, expected subtype of Real(start=1.0), got type Real[3]. The model is attached. Can anybody please give me some guidance on how to correct this error.


WEC1.mo

Thankyou.