function [sys,x0,str,ts] = Static_friction_torque(t,x,u,flag)
%
% Dispatch the flag. The switch function controls the calls to 
% S-function routines at each simulation stage of the S-function.
%
switch flag,
  %%%%%%%%%%%%%%%%%%
  % Initialization %
  %%%%%%%%%%%%%%%%%%
  % Initialize the states, sample times, and state ordering strings.
  case 0
    [sys,x0,str,ts]=mdlInitializeSizes;

  %%%%%%%%%%%
  % Outputs %
  %%%%%%%%%%%
  % Return the outputs of the S-function block.
  case 3
    sys=mdlOutputs(t,x,u);

  %%%%%%%%%%%%%%%%%%%
  % Unhandled flags %
  %%%%%%%%%%%%%%%%%%%
  % There are no termination tasks (flag=9) to be handled.
  % Also, there are no continuous or discrete states,
  % so flags 1,2, and 4 are not used, so return an emptyu
  % matrix 
  case { 1, 2, 4, 9 }
    sys=[];

  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  % Unexpected flags (error handling)%
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  % Return an error message for unhandled flag values.
  otherwise
    error(['Unhandled flag = ',num2str(flag)]);

end

% end timestwo

%
%=============================================================================
% mdlInitializeSizes
% Return the sizes, initial conditions, and sample times for the S-function.
%=============================================================================
%
function [sys,x0,str,ts] = mdlInitializeSizes()

sizes = simsizes;
sizes.NumContStates  = 0;
sizes.NumDiscStates  = 0;
sizes.NumOutputs     = 1;  % dynamically sized
sizes.NumInputs      = 3;  % 1=signo veloc; 2=Par electromagnético; 3=P rozamiento
sizes.DirFeedthrough = 1;   % has direct feedthrough
sizes.NumSampleTimes = 1;

sys = simsizes(sizes);
str = [];
x0  = [];
ts  = [-1 0];   % inherited sample time

% end mdlInitializeSizes

%
%=============================================================================
% mdlOutputs
% Return the output vector for the S-function
%=============================================================================
%
function sys = mdlOutputs(t,x,u)

sig_v=sign(u(1));					% Signo de la velocidad
P_elm=u(2);					% Par electromagnético
P_roz=u(3);					% Par de rozamiento estático

if sig_v>0   				% Si ˇPar_elect.ˇ > Par_roz  
   
   sys = P_elm-P_roz;
   
elseif sig_v<0   				% Si ˇPar_elect.ˇ > Par_roz  
   
   sys = P_elm+P_roz;
   
else  							% Si ˇPar_elect.ˇ > Par_roz  
   
   if abs(P_elm)>P_roz 
      sys = P_elm-sign(P_elm)*P_roz;
  	else
      sys = 0;
   end
       
end
% end mdlOutputs