Hi All,

I am new to Simulink and have come across the same Simulink error several times and I don't know how to fix it. Basically I have created an Embedded Matlab function block in Simulink with the following code inside:


function newPsi =dynamics(curHead,ra1,maxTurnRate,TurnRate,cmdHeading,dt)
if (TurnRate>maxTurnRate)
    ra=maxTurnRate;
elseif (TurnRate <(-1*maxTurnRate))
    ra=-maxTurnRate;
else
    ra=TurnRate;
end

if ((cmdHeading-curHead)<=0) 
    newPsi=cmdHeading;
else 
    newPsi=curHead+(((ra+ra1)/2)*dt);
end


All of the inputs are constant except for dt which is the time and curHead is a feeback loop from newPsi that has an IC block attached to it.  Pretty simple code but I keep getting the same error: Simulink cannot solve the algebraic loop containing 'NICE4/Embedded MATLAB Function4' at time 0.02 using the TrustRegion-based algorithm due to one of the following reasons: the model is ill-defined i.e., the system equations do not have a solution; or the nonlinear equation solver failed to converge due to numerical issues.

I have no idea how fix the algebraic loop. Any help would be greatly appreciated.

Thanks,
Meagan

Make sure that you do not have a signal line going out and then coming back 
into the EML block you
created. If there is such a line then add a delay (z^-1) block.

mbelge

"Meagan " <meagan.musselman@l-3com.com> wrote in message 
news:i94bk7$206$1@fred.mathworks.com...
> Hi All,
>
> I am new to Simulink and have come across the same Simulink error several 
> times and I don't know how to fix it. Basically I have created an Embedded 
> Matlab function block in Simulink with the following code inside:
>
>
> function newPsi =dynamics(curHead,ra1,maxTurnRate,TurnRate,cmdHeading,dt)
> if (TurnRate>maxTurnRate)
>    ra=maxTurnRate;
> elseif (TurnRate <(-1*maxTurnRate))
>    ra=-maxTurnRate;
> else
>    ra=TurnRate;
> end
>
> if ((cmdHeading-curHead)<=0) newPsi=cmdHeading;
> else newPsi=curHead+(((ra+ra1)/2)*dt);
> end
>
>
> All of the inputs are constant except for dt which is the time and curHead 
> is a feeback loop from newPsi that has an IC block attached to it.  Pretty 
> simple code but I keep getting the same error: Simulink cannot solve the 
> algebraic loop containing 'NICE4/Embedded MATLAB Function4' at time 0.02 
> using the TrustRegion-based algorithm due to one of the following reasons: 
> the model is ill-defined i.e., the system equations do not have a 
> solution; or the nonlinear equation solver failed to converge due to 
> numerical issues.
>
> I have no idea how fix the algebraic loop. Any help would be greatly 
> appreciated.
>
> Thanks,
> Meagan
>