MISO model control system Tuning failed

I use Workflow in MATLAB build a 2 input 1 output system as below: for Block see attatched file for matlab code below: bj22221 is a 2 input and 1 output model which I build by ident GUI.

G=bj22221; G.InputName = {'Dh', 'Dp'}; G.OutputName = 'y';

C_Dh = ltiblock.pid('C_Dh','pid'); C_Dh.TimeUnit = 'seconds';C_Dh.u = 'qDh'; C_Dh.y = 'Dh';

C_Dp = ltiblock.pid('C_Dp','pid'); C_Dp.TimeUnit = 'seconds';C_Dp.u = 'qDp'; C_Dp.y = 'Dp';

D= ltiblock.gain('Decouple', eye(2,1));D.u='e';D.y={'qDh', 'qDp'};D.TimeUnit = 'seconds';

Sum = sumblk('e = r-y',1);

C_Dh.Ts=0.1; C_Dp.Ts=0.1; D.Ts=0.1;Sum.Ts=0.1;G.Ts=0.1;

C=connect(D,C_Dh,C_Dp,Sum,{'r','y'}, {'Dh','Dp'});

wc = [0.1,1];

[G,C,gam,Info] = looptune(G,C,wc);

Final: Failed to enforce closed-loop stability (max z = 1)

Failed to stabilize closed-loop system. Try different initial values or increase the number of random starts using "systuneOptions".

I can not solve the problem, hope some one can give me a help.

foxtan

[Arkadiy Turevskiy]

Impossible to provide help without having access to plat model. Can you attach your plant model (bj2221) in a .mat file? When you create this model in System Identification Toolbox, you can export it to MATLAB workspace anf then save to .mat file.

Arkadiy