Error evaluating parameter 'Value' in simulink

Hi,

I am using simulink to calculate ballistics flights. Until now a used :

[time, state, output]=sim ('ballistic_flight_3',15); within an m-file In this m-file the input for the simulation were given in nromal way:

nameVar=valueVar

now in a next step I had to change this m-file to a function, the function is normally identical to the m-file, all teh same variables are used and assigned the same values within the function

function [FlightDistMat,FlightDistSim]=CompareBallisticFu(LaunchAngleDeg,HorLaunchSpeedMps,DiamM, UseSimulink)

For ..... Cr=0.44; HorStartPos=0; HorVertPos=1; .... [time, state, output]=sim ('ballistic_flight_3',15); ...

end

Now I get error on the line were I call: [time, state, output]=sim ('ballistic_flight_3',15);

Error evaluating parameter 'Value' in 'ballistic_flight_3/Cr': Error using ==> sim Undefined function or variable 'Cr'.

The strange this is : if I run the m-file first and then I try calling the function again, it works,

So I found that if I load the vars in the workspace first it worksn while those same vars are defined in the function???

Looking for solutions on the internet I looked at 'Initialising Simulink Model Parameter Variables using Callbacks' but I was not able to solve my problem also tried setting the model workspace via the model explorer but I think that is the wrong way because some of the values are changed in my function for each time that I call the simulation

thanks for any help

regards,

I use Simulink 7.0 R2007b

[TAB]

The strange this is : if I run the m-file first and then I try calling the function again, it works

From where you are running the m-file and function ?

I think it may be due to that, you are accessing matlab's base workspace variables inside a function. In matlab each function has it's own workspace and data from base workpsace can not be accessed directly in function.

[Jürgen]

I do not completely understand your question: the mfile: CompareBallistic.m is called from the command line the function [FlightDistMat,FlightDistSim]=CompareBallisticFu(LaunchAngleDeg,HorLaunchSpeedMps,DiamM, UseSimulink) is also called from the function line

What is also strange in the m-file a define some vars=

drag, vertpos,horpos.. , I define the same var in the function but it seems he does not accept this for input in the simulink model BUT if I load those vars in the workspace just before I run the function it works also!!

[Jürgen]

Hi, need to add some thing, I start searching what you meant with base workspace and indeed if I clear the workspace, and then perform the function I can see in workspace that my vars are in the stack but not in the base, if I do the m-file first the are in base and in stack? I am not familiar with this...base vs stack, normally all vars defined within the function should be available no?

Answer 1

[TAB]

Ok, I think I got the problem.

By default the source workspace for simulink model is base workspace. So when you simulate the model, it resolves the parameters from base workspace.

As your parameters are in function workspace your model is not taking these parameters.

So you can resolve it in two ways...

1. Exports the parameters from the function to base workspase using assignin() or evalin() commands before simulating the model.

2. Change the source workspace of your model to current (function) workspace using simset() command. See How do I run a model from my MATLAB function.

[Jürgen]

indeed seems logical , thanks for the help , I'll implement it

Answer 2

[Moti Bekuma]

please help me on this. when i run it it says

Invalid setting in 'The_overall_quadrotor_yaw_attitude_model/From Workspace' for parameter 'VariableName'.

Error evaluating parameter 'VariableName' in 'The_overall_quadrotor_yaw_attitude_model/From Workspace'

Undefined variable "PRBS" or class "PRBS.mat".