Modelling and Control of Three-link Planar Robot for Stable Walking Gait

Control of a passive walking robot has been a challenging problem in energy efficient two-legged robot. This paper proposes the modelling and control for a passive walking planar robot to achieve stable walking with an additional link representing the upper body. The dynamic model for a three-link planar robot under consideration is derived for both walking phase and during impact. The dynamics is used along with suitable initial conditions to generate the reference trajectory for stable walking. The results show that the robot follows the generated reference trajectory with the use of a controller developed using feedback linearization control law. The proposed controller is studied and validated using simulations and it is observed that the walking trajectory converges to a stable limit cycle. Thus the model can be extended to realize energy efficient walking of a biped robot with upper body mass.