Contact Force Distribution Using Centroidal Momentum Feedback for Quadruped Locomotion

This paper proposes a method to distribute contact forces to eliminate undesired torso orientation fluctuations and regulate heading during dynamic quadruped trot-walking motion. The proposed method makes use of centroidal momentum, an essential physical quantity in characterizing the whole-body behavior and overall balance of the robot. The contact forces are computed using centroidal momentum feedback and injected into the locomotion controller via virtual model control, which can render virtual forces to regulate robot-environment interaction. In combining the virtual model control and centroidal momentum feedback, one can attain dynamically feasible contact force distribution, a key objective in controlling dynamic quadruped locomotion. In order to validate the proposed method, a series of simulation experiments were conducted using a realistic model of our quadruped robot Kara. As a result, we obtained dynamically consistent trot-walking behavior in which torso orientation and heading were well regulated.