Passivity Based Whole-body Control for Quadrupedal Locomotion on Challenging Terrain (RAL)

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We present a passivity-based Whole-Body Control approach for quadruped robots that achieves dynamic locomotion while compliantly balancing the robot’s trunk. We formulate the motion tracking as a Quadratic Program (QP) that takes into account the full robot rigid body dynamics, the actuation limit, the joint limits and the contact interaction. We analyze the controller robustness against inaccurate friction coefficient estimates and unstable footholds, as well as its capability to redistribute the load as a consequence of enforcing actuation limits. Additionally, we present some practical implementation details gained from the experience with the real platform. Extensive experimental trials on the 90 Kg Hydraulically actuated Quadruped (HyQ) robot validate the capabilities of this controller under various terrain conditions and gaits. The proposed approach is expedient for accurate execution of high dynamic motions with respect to the current state of the art. Drawing Drawing