问题
I would like to adjust some Simulink parameters programmatically, namely specifying external inputs and initial state. The Mathworks' help document on Data Import/Export shows how to do so both visually and programmatically. Apparently for external inputs, I need to specify LoadExternalInputs to 'on'; I would like to override the default external input via ExternalInput to [myTimeVar, myInputVar], as documented in that link.
Trying to run the command
sim('mySim', 'LoadExternalInputs', 'on', 'ExternalInput', [myTimeVar, myInputVar]);
yields the following error message:
Invalid setting in block_diagram 'mySim' for parameter 'ExternalInput'
If I'm not supposed to specify my external input in the sim() call, where am I supposed to do it? I'm quite confused as to how to specify my inputs and states.
回答1:
The ExternalInput parameter must be a string, try this:
sim('mySim', 'LoadExternalInputs', 'on', 'ExternalInput', '[myTimeVar, myInputVar]');
回答2:
As pointed out by @MikeT, the sim command works in a parameter name-value fashion, so both the parameter name and value must be strings. The command should be:
sim('mySim','LoadExternalInput', 'on', 'ExternalInput', [myTimeVar, myInputVar]);
I believe the parameter 'LoadExternalInput' is not necessary, but in any case, it is 'LoadExternalInput' rather than 'LoadExternalInputs'. I checked it with get_param('modelName','ObjectParameters')
Some important remarks:
Remark #1:
When using sim, Simulink automatically switches the workspace to the model's, so one might get errors if sim is executed within a MATLAB function or unitTest.
Remark #2
In the pair 'ExternalInput','Inputs', 'Inputs' should contain the column-wise concatenation of all the column vectors inputs, starting with the time vector: '[myTimeVar, myInputVar1, myInputVar2, ..., myInputVarN]', all of them column vectors.
回答3:
help sim in MATLAB shows me a different command format than what you're using:
[t,x,y] = sim(model,timespan,options,ut);
I think maybe this is what you want?
sim('mySim', myTimeSpan, [], [myTimeVar, myInputVar]);
(where myTimeSpan is the time span to simulate over)
来源：https://stackoverflow.com/questions/8597078/simulink-programmatically-specifying-external-inputs