function [ssc]=testObserver(mot)
  %http://ctms.engin.umich.edu/CTMS/index.php?example=Introduction&section=ControlStateSpace
  mdl=1; % 0:hovering ball  1:fast stage
  if mdl==0
    A = [ 0   1   0
         980  0  -2.8
          0   0  -100 ];

    B = [ 0
          0
          100 ];

    C = [ 1 0 0 ];
    D=0;
  else
    [A,B,C,D]=ssdata(mot.ssMdl);
    C=C(3,:);D=D(3);    
    numc=(mot.mdl.numc);
    denc=(mot.mdl.denc);
    num1=(mot.mdl.num1);
    den1=(mot.mdl.den1);

    g1=tf(numc,denc);  % iqCmd->iqMeas
    s1=ss(g1);
    s1.C=[s1.C; 1E5* 2.4E-3 1E-3*s1.C(2)*8.8];   % add output iqVolts: iqVolts= i_meas*R+i_meas'*L 2.4mH 8.8Ohm (took random scaling values)
    g2=tf(num1,den1); %iqMeas->ActPos without resonance frequencies
    s2=ss(g2);
    s3=append(s1,s2);
    s3.A(3,2)=s3.C(1,2)*s3.B(3,2);    
    
    %d=.77;w0=9100; %1.44kHz -> T0=6.9046e-04
    %numc=[w0^2];
    %denc=[1 d*2*w0 w0^2];
    %T0=6E-4;  %w=1/1E-3=1E3 -> f=w/(2pi)=1000/6.2=159Hz
    %numc=[1];
    %denc=[T0^2 d*2*T0 1];
    %bode(numc,denc)
    
    num=conv(numc,num1);%num=1;
    den=conv(denc,den1);%den=[1 0 0];
    g4=tf(num,den); %iqMeas->ActPos
    s4=ss(g4);  
    mot.ssMdl
    s3
    s4
    [A,B,C,D]=ssdata(s4);
  end
  
  Ap=A;Am=A;
  Bp=B;Bm=B;
  Cp=C;Cm=C;
  Dp=D;Dm=D;Dt=D;

  poles = eig(A);
  disp(poles);

  
  if mdl==0
    t = 0:0.01:2;
    u = zeros(size(t));
    x0 = [0.01 0 0];

    sys = ss(A,B,C,D);

    [y,t,x] = lsim(sys,u,t,x0);
    plot(t,y)
    title('Open-Loop Response to Non-Zero Initial Condition')
    xlabel('Time (sec)')
    ylabel('Ball Position (m)')

    p1 = -10 + 10i;  p2 = -10 - 10i; p3 = -50;
    K = place(A,B,[p1 p2 p3]);
    sys_cl = ss(A-B*K,B,C,0);
    lsim(sys_cl,u,t,x0);
    xlabel('Time (sec)')
    ylabel('Ball Position (m)')

    p1 = -20 + 20i; p2 = -20 - 20i; p3 = -100;
    P=[p1 p2 p3];
    K = place(A,B,P);
    sys_cl = ss(A-B*K,B,C,0);
    lsim(sys_cl,u,t,x0);
    xlabel('Time (sec)')
    ylabel('Ball Position (m)')
 
    t = 0:0.01:2;
    u = 0.001*ones(size(t));

    sys_cl = ss(A-B*K,B,C,0);

    lsim(sys_cl,u,t);
    xlabel('Time (sec)')
    ylabel('Ball Position (m)')
    axis([0 2 -4E-6 0])

    V=-1./(Cm*(Am-Bm*K)^-1*Bm); %(from Lineare Regelsysteme2 (Glattfelder) page:173 )
    lsim(sys_cl,V*u,t)
    title('Linear Simulation Results (with Nbar)')
    xlabel('Time (sec)')
    ylabel('Ball Position (m)')
    axis([0 2 0 1.2*10^-3])     
  else
    x0 = [0 0 0 0];
    p1=-63+2.80i;
    p2=-62+1.50i;   
    P=[p1 p1' p2 p2'];
    P=[-4000+100j -4000-100j -500+10j -500-10j];
    K = place(A,B,P);
    Ts=1/5000
    t = 0:Ts:2;
    u = 0.001*ones(size(t));
    V=-1./(Cm*(Am-Bm*K)^-1*Bm); %(from Lineare Regelsysteme2 (Glattfelder) page:173 )
    sys_cl = ss(A-B*K,B*V,C,0);

    lsim(sys_cl,u,t,x0);
    xlabel('Time (sec)')
    ylabel('Motor Position (m)')
    axis([0 2 0 1.2E-3])
  end

  if mdl==0
    op1 = -100;
    op2 = -101;
    op3 = -102;
    OP=[op1,op2,op3];
    OP=P*2;
    L = place(A',C',OP)';
    At = [ A-B*K             B*K
           zeros(size(A))    A-L*C ];
    Bt = [    B*V
           zeros(size(B)) ];
    Ct = [ C    zeros(size(C)) ];

    sys = ss(At,Bt,Ct,0);
    %lsim(sys,zeros(size(t)),t,[x0 x0]);
    lsim(sys,u,t,[x0 x0]*0);
    title('Linear Simulation Results (with observer)')
    xlabel('Time (sec)')
    ylabel('Ball Position (m)')
  else
    OP=P*2;
    L = place(A',C',OP)';
    At = [ A-B*K             B*K
           zeros(size(A))    A-L*C ];
    Bt = [    B*V
           zeros(size(B)) ];
    Ct = [ C    zeros(size(C)) ];

    sys = ss(At,Bt,Ct,0);
    lsim(sys,u,t,[x0 x0]*0);
    title('Linear Simulation Results (with observer)')
    xlabel('Time (sec)')
    ylabel('Motor Position (m)')
    axis([0 2 0 1.2E-3])
  end  
  
  if mdl==0
    t = 0:1E-6:0.1;
    x0 = [0.01 0.5 -5];
    [y,t,x] = lsim(sys,zeros(size(t)),t,[x0 x0]);

    n = 3;
    e = x(:,n+1:end);
    x = x(:,1:n);
    x_est = x - e;

    % Save state variables explicitly to aid in plotting
    h = x(:,1); h_dot = x(:,2); i = x(:,3);
    h_est = x_est(:,1); h_dot_est = x_est(:,2); i_est = x_est(:,3);

    plot(t,h,'-r',t,h_est,':r',t,h_dot,'-b',t,h_dot_est,':b',t,i,'-g',t,i_est,':g')
    legend('h','h_{est}','hdot','hdot_{est}','i','i_{est}')
    xlabel('Time (sec)')
  end
  
  
  %discrete
  Ts=1/5000; % deltatau std. frq. is 5kHz
  %The discrete system works with sampling >100Hz,. the bigger the frequency the better the result
  %With sampling = 80Hz hte system already becomes instable.
  ss_t=ss(At,Bt,Ct,Dt);
  %figure();pzplot(ss_t)
  ss_tz=c2d(ss_t,Ts);
  %figure();pzplot(ss_tz)
  [Atz,Btz,Ctz,Dtz]=ssdata(ss_tz);

  
  [Apz,Bpz,Cpz,Dpz]=ssdata(c2d(ss(Ap,Bp,Cp,Dp),Ts));
  [Amz,Bmz,Cmz,Dmz]=ssdata(c2d(ss(Am,Bm,Cm,Dm),Ts));
  

  Ao=Am-L*Cm;
  Bo=[Bm L];
  Co=K;
  Do=zeros(size(Co,1),size(Bo,2));
  
  [Aoz,Boz,Coz,Doz]=ssdata(c2d(ss(Ao,Bo,Co,Do),Ts));
  
  
  %state space controller
  ssc=struct();
  for k=["Ts","At","Bt","Ct","Dt","Atz","Btz","Ctz","Dtz","Ap","Bp","Cp","Dp","Am","Bm","Cm","Dm","Ao","Bo","Co","Do","Apz","Bpz","Cpz","Dpz","Aoz","Boz","Coz","Doz","V","K","L"]
    ssc=setfield(ssc,k,eval(k));
  end
  mdlName='testObserverSim';
  open(mdlName);
  
  
  
end