de conits aériens par une régulation subliminale en vitesse PMP conditions on postzone For all (xi, vi, z1,i, z2,i, z0,i, ui), the Hamiltonian of problem (Pi) is : Hi (xi(t), vi(t), z1,i(t), z2,i(t), z0,i, ui(t)) = z1,i(t)vi(t)di + z2,i(t)ui(t) + z0,iu 2 i (t). We obtain, for almost each instant t in [tZ, tf ]: ˙ xi(t) = vi(t)di, ˙ vi(t) = z2,i(t) 2 , ˙ z1,i(t) = 0 R 2 , ˙ z2,i(t) = − z1,i(t)di. ui(t) = v tf i − v tZ i tf − tZ , vi(t) = v tf i − v tZ i tf − tZ (t − tf ) + v tf i , xi(t) = v tf i − v tZ i tf − tZ di t2 2 + v tf i − v tf i − v tZ i tf − tZ tf dit − v tf i − v tZ i tf − tZ (tZ − tf ) + v tf i ditZ + x tZ i . Result: On [tZ, tf ], the optimal acceleration is constant ! 15/38