function xp = cap8_robot2gdlTANH(t,x)
%vector de posición articular
    q1=x(1); q2=x(2); q = [q1; q2];
    
%vector de velocidad articular
    qp1=x(3);     qp2=x(4); qp = [qp1; qp2];

   m1=23.902;   l1=0.45; lc1=0.091;  I1=1.266; b1=2.288;
   m2=3.880;    l2=0.45; lc2=0.048; I2=0.093; b2=0.175; g=9.81;   
   
  theta1=m1*lc1*lc1+m2*l1*l1+m2*lc2*lc2+I1+I2;
  theta2=l1*m2*lc2;
  theta3=m2*lc2*lc2+I2;
  theta4=g*(lc1*m1+m2*l1); theta5=g*m2*lc2;
  theta6=b1;  theta7=b2;
   
 M=[theta1+2*theta2*cos(q2), theta3+theta2*cos(q2);
    theta3+theta2*cos(q2), theta3];
 
 
 C=[ -2*theta2*sin(q2)*qp2, -theta2*sin(q2)*qp2;
     theta2*sin(q2)*qp1, 0];
 
 gq11=theta4*sin(q1)+theta5*sin(q1+q2);
 gq21=theta5*sin(q1+q2);
 gq=[gq11; gq21];
 
 fr=[theta6*qp1;
     theta7*qp2]; 
           
 [~ , tau]=cap8_TANHrobot2gdl(q,qp);
qpp = M^(-1)*(tau-C*qp-gq-fr);


%vector de salida\n
xp = [qp1; qp2; qpp(1); qpp(2)];
end