function [omega_m,omega_3,dotl]= Fermeture_cinematique(l,theta_m,theta_3,theta_1,omega_1)
c=0.08;
p=0.004;
dotl=-sin(theta_1-theta_3)*c*omega_1;
omega_m=(2*pi/p)*dotl;
omega_3=c*omega_1*cos(theta_1-theta_3)/l;