Dynamic On-Palm Manipulation via Controlled Sliding
RSS• 2024
Abstract
Non-prehensile manipulation enables fast interactions with objects by
circumventing the need to grasp and ungrasp as well as handling objects that
cannot be grasped through force closure. Current approaches to non-prehensile
manipulation focus on static contacts, avoiding the underactuation that comes
with sliding. However, the ability to control sliding contact, essentially
removing the no-slip constraint, opens up new possibilities in dynamic
manipulation. In this paper, we explore a challenging dynamic non-prehensile
manipulation task that requires the consideration of the full spectrum of
hybrid contact modes. We leverage recent methods in contact-implicit MPC to
handle the multi-modal planning aspect of the task. We demonstrate, with
careful consideration of integration between the simple model used for MPC and
the low-level tracking controller, how contact-implicit MPC can be adapted to
dynamic tasks. Surprisingly, despite the known inaccuracies of frictional rigid
contact models, our method is able to react to these inaccuracies while still
quickly performing the task. Moreover, we do not use common aids such as
reference trajectories or motion primitives, highlighting the generality of our
approach. To the best of our knowledge, this is the first application of
contact-implicit MPC to a dynamic manipulation task in three dimensions.