Tactile-based compliance with hierarchical force propagation for omnidirectional mobile manipulators

In this paper, we address the issue of whole-body compliance with hierarchical force propagation for omnidirectional mobile manipulators. Using the multimodal tactile feedback (force and proximity) provided by an artificial skin, our objective is to generate prioritized compliant behaviors in response to multicontact physical interactions between a mobile robot and its external environment. To be more specific we want the force components which cannot be properly propagated using upper-limbs, to be projected onto the mobile base in order to generate suitable compliant motions. Using Quadratic Programming (QP), we propose a general method allowing to properly estimate and propagate these force components while respecting the robot physical constraints. In this way, a robust human-like whole-body compliance can be achieved. We finally test and validate our method on a complex robot system.