Abstract:

This video shows the latest results in the whole-body control of humanoid robots achieved by the Dynamic Interaction Control Lab at the Italian Institute of Technology. In particular, the control architecture is composed of two nested control loops. The internal loop, which runs at 1 KHz, is in charge of stabilizing any desired joint torque. This task is achieved thanks to an off-line identification procedure providing us with a reliable model of friction and motor constants. The outer loop, which generates desired joint torques at 100 Hz, is a momentum based control algorithm in the context of free-floating systems. More precisely, the control objective for the outer loop is the stabilization of the robot’s linear and angular momentum and the associated zero dynamics. The latter objective can be used to stabilize a desired joint configuration. The stability of the control framework is shown to be in the sense of Lyapunov. The contact forces and torques are regulated so as to break contacts only at desired configurations. Switching between several contacts is taken into account thanks to a finite-state-machine that dictates the constraints acting on the system. The control framework is implemented on the iCub humanoid robot.