Decentralized Admittance Control for a Multi–manipulator System: Theory and Experiments
Graziano Carriero, Monica Sileo, Sebastiano Fregnan, Francesco Pierri, Fabrizio Caccavale, Yiannis Karayiannidis
Abstract
This paper presents a decentralized control framework for cooperative object transportation with multiple robotic manipulators. In particular two admittance schemes are designed in order to regulate external contact wrenches and internal interaction wrenches without a central unit or all-to-all communication. Each manipulator estimates the wrenches exerted by its teammates through a bank of consensus-based observers that exploits a strongly connected communication graph. These estimates feed two local admittance filters: an external filter, computing the reference object trajectory while limiting environmental wrenches, and an internal filter, generating the end-effector trajectory to minimize each robot’s contribution to internal wrenches. Experiments carried out with three 7-DOF Franka Emika Panda arms show a marked reduction of both external and internal wrenches, demonstrating the effectiveness and robustness of the proposed approach.