function y  = bdot(u)
% This block supports an embeddable subset of the MATLAB language.
% See the help menu for details.
persistent h;
persistent cont;
persistent u_old;
k = 0';

if isempty(h)
  h = 0;
  cont = 0;
  u_old = 0;
end
%u = u;
switch h
  case 0
    cont = 0.049*(u(1:3)-u_old(1:3)+cont(1:3)*0.0759);
    u_old = u;
    k(1:3) = cont;    
    h = h+1;
  case 9
    h = 0;
  otherwise
    k(1:3) = cont;
    h = h +1;
end
y = k;