On Observer-Based Feedback Stabilization of Periodic Orbits in Bipedal Locomotion

This communication develops an observer-based feedback controller for the stabilization of periodic orbits arising in bipedal robots. The robot is modeled as a system with impulse effects and it is assumed that the robot’s configuration variables are measured and that the moment of impact of the swing leg with the ground can be detected as well. It is shown that if a continuously differentiable static state variable feedback controller exists that induces an exponentially stable periodic orbit, then the same orbit can be exponentially stabilized with a continuously differentiable output feedback controller.