The analysis of the simplest biped walking machine can provide much insight into dynamics and control of humain gait. The problem, in the sagittal plane, consists to control the impulse force under the swing foot and the torque between the legs in order to reach a stable limit cycle. The main contribution of this paper concerns the hierarchical control based on the physiological Lambda model and a pattern generator working with intermittent data. The feedback is tuned in order to obtain oscillation at the walking frequency. Simulation results present stable limit cycle.